全球定位系统毕业论文外文文献翻译

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北斗定位-毕业论文外文文献翻译

外文文献原稿和译文原稿Beidou positioningPrefaceNavigation satellite systems can provide all time, all weather and high accuracy positioning, navigation and timing services to users on the earth surface or in the near-earth space. It is an important space inf rastructure, which extends people’s range of activities and promotes social development. Satellite navigation is bringing up revolutionary changes to the world politics, economy, military, technology and culture.With a long history and a splendid culture, China is one of the important cradles of early human civilization. In ancient times, Chinese people used the Big Dipper (Beidou) for identifying directions, and invented the world’s first navigation device, the ancient compass (Sinan), which was a great contribution to the development of world civilization. In modern society, the Chinese-built BeiDou（COMPASS） system will become another contribution to the mankind.In early 1980s, China began to actively study the navigation satellite systems in line with C hina’s conditions. In 2000, BeiDou Navigation Demonstration System is basically established, which made China the third nation in possession of an independent navigation satellite system following the United States and Russia. At present, China is steadily accelerating the construction of the BeiDou Navigation Satellite System, and has already successfully launched 10 satellites so far.The BeiDou system will meet the demands of China’s national security, economic development, technological advances and social progress, safeguard national interests and enhance the comprehensive national strength. The BeiDou system will commit to providing stable, reliable and quality satellite navigation services for global users. Along with other GNSS providers, the BeiDou system will jointly promote the development of satellitenavigation industry, make contributions to human civilization and social development, serve the world and benefit the mankind.I. System DescriptionThe BeiDou system is comprised of three major components: space constellation, ground control segment and user terminals. The space constellation consists of five GEO satellites and 30 non-GEO satellites. The GEO satellites are positioned at 58.75°E, 80°E, 110.5°E, 140°E and 160°E respectively. The non-GEO satellites include 27 MEO satellites and three IGSO satellites. The MEO satellites are operating in an orbit with an altitudeof 21,500 km and an inclination of 55°, which are evenly distributed in three orbital planes. The IGSO satellites are operating in an orbit with an altitude of 36,000 km and an inclination of 55°, which are evenly distributed in three inclined geo-synchronous orbital planes. The subsatellite track for the three IGSO satellites are coincided while the longitude of the intersection point is at 118°E, with a phase difference of 120°.Ground control segment consists of several Master Control Stations (MCS), Upload Stations (US) and a network of globally distributed Monitor Stations (MS). The main tasks of MCS are to collect observing data from each MS, to process data, to generate satellite navigation messages, wide area differential data and integrity information, to perform mission planning and scheduling, and to conduct system operation and control. The main tasks of Upload Stations include completing the upload of satellite navigation messages, wide area differential data and integrity information, controlling and managing the payload. The tasks of Monitor Stations include continuous tracking and monitoring of navigation satellites, receiving navigation signals, sending observational data to the Master Control Station for the satellites orbit determination and time synchronization.The user terminals include various BeiDou user terminals, and terminals compatible with other navigation satellite systems, to meet different application requirements from different fields and industries.The time reference for the BeiDou Navigation Satellite System uses BeiDou Time (BDT). BDT’s length of second is a SI second. BDT was zero at 0:00:00 on Janu ary 1, 2006 Coordinated Universal Time (UTC). BDT is a continuous system, traceable to the UTC time maintained by the National Time Service Center (NTSC) of ChineseAcademy ofSciences, which is referred to as UTC (NTSC). The leap seconds with UTC information is broadcasted in the navigation messages. The difference between BDT and UTC maintains within 100ns.The coordinate framework of BeiDou system adopts China Geodetic Coordinate System 2000 (CGCS2000).Upon the full system completion, the BeiDou Navigation Satellite System can provide positioning, navigation and timing services to worldwide users. It can also provide wide area differential services with the accuracy of 1m and short messages services with the capacity of 120 Chinese characters each time.·Main functions: positioning, velocity measurement, one-way and two-way timing, short messages·Service area: global·Positioning accuracy: better than 10m·Velocity accuracy: better than 0.2m/s·Timing accuracy: 20nsII. System DevelopmentThe BeiDou system has followed the development concept of starting with regional services first and expanding to global services later. A three-step development strategy has been taken, with specifics as follows:Phase I: BeiDou Navigation Satellite Demonstration System. In 1994, Chinastarted the construction of BeiDou Navigation Satellite Demonstration System. In 2000, two BeiDou navigation experiment satellites were launched, and the BeiDou Navigation Satellite Demonstration System was basically established. In 2003, the third BeiDou navigation experiment satellite was launched, further enhancing the performance of the BeiDou Navigation Satellite Demonstration System.BeiDou Navigation Satellite Demonstration System consists of three major components: space constellation, ground control segment and user terminals. The space constellation includes three geostationary orbit (GEO) satellites, positioned at longitude of 80 degrees East, 110.5 degrees East and 140 degrees East respectively above the equator. Ground control segment consists of the ground control center and a number of calibrationstations. The ground control center is to complete satellite orbit determination, ionospheric correction, user location determination and user short message information exchange and processing. The calibration ground control stations are mainly to provide the distance measurement and correction parameters to the ground control center.The user terminals include the hand-held type, vehicle type, command type and other types of terminals, capable of position service application, location coordinates information receiving and other functions.The main functions and performance specifications of the BeiDou Navigation Satellite Demonstration System are as follows:·Main functions: positioning, one-way and two-way timing, short message communications;·Service Area: China and the surrounding areas;·Positioning Accuracy: better than 20 meters;·Timing Accuracy: 100 ns one-way, two-way 20 ns;·Short message communications: 120 Chinese characters per time.Phase II: BeiDou Navigation Satellite (regional) System. In 2004, Chinastarted construction of BeiDou Navigation Satellite System. In 2007, the first satellite, a round medium earth orbit satellite (COMPASS-M1) was launched. By 2012, the BeiDou system will consist of 14 satellites, including five GEO satellites, five IGSO satellites (two in-orbit spares), and four MEO satellites.The functions and performance parameters of BeiDou Navigation Satellite (regional) System are as follows:·Main functions: positioning, velocity measurement, one-way and two-way timing, short message communications;·Service Area: China and part of Asia- Pacific region ;·Positioning Accuracy: better than 10 meters;·Velocity Accuracy: better than 0.2 m/s;·Timing Accuracy: 50 ns;·Short message communications: 120 Chinese characters per message.Phase III: BeiDou Navigation Satellite System will completely be established by 2020.III. System ApplicationsSince it was officially brought into service in 2003, the BeiDou Navigation Satellite Demonstration System has been widely used in transportation, marine fisheries, hydrological monitoring, weather forecasting, forest fire prevention, timing for communication systems, power distribution, disaster mitigation, national security, and many other fields, which has been resulting in significant social and economic benefits. Particularly, the system has played an important role in the South China frozen disaster, earthquake relief in Wenchuan, SichuanProvince and Yushu, Qinghai Province, the Beijing Olympic Games, and the Shanghai World Expo.—In the field of transportation, built on the Beidou Navigation Satellite Demonstration System, applications such as Xinjiang Satellite Navigation Monitoring System of Public Transport, the Highway Infrastructure Safety Monitoring System, and the Port Scheduling High-precision Real-time Position Monitoring System, have promoted the BeiDou system and achieved a good demonstration effect.—In marine fisheries, built on the BeiDou Navigation Satellite Demonstration System, the marine fisheries integrated information service platform has provided vessel position monitoring, emergency rescue, information distribution, fishing boats in and out of port management and other services to the fishery administration departments.—The hydrological monitoring system, based on the BeiDou Navigation Satellite Demonstration System, has realized the real-time transmission of hydrological forecast information in mountainous regions, which has improved the accuracy o f the disaster forecasting and has helped the planning and scheduling programs for the flood and drought control.—In the field of weather forecasting, a series of BeiDou terminal equipment have been developed for weather forecast, and various practical and feasible system solutions have been worked out to address the automatic data transmission issues for the China Meteorological Administration and a number of local weather centers and stations.—In the field of forest fire prevention, the BeiDou Navigation Satellite Demonstration System has been successfully used in forest fire prevention system. Its positioning and short message communication services have achieved good results.—In the field of time synchronization for communication systems, the successful implementation of BeiDou two-way timing demonstration program has achieved breakthroughs in some key technical areas such as long distant fiber technology, and an integrated satellite-based timing system has been developed.—In the field of power distribution, built on the BeiDou Navigation Satellite Demonstration System, the successful implementation of power system time synchronization demonstration program has created basis for the high precision applications such as the electric accident analysis, the electricity early warning and protection systems.—In the field of disaster mitigation, the navigation, positioning, short message communications and position reporting capabilities of the BeiDou Navigation Satellite Demonstration System have provided services for the nationwide real-time disaster relief commanding and dispatching, emergency communications, rapid reporting and sharing of disaster information, which has significantly improved the rapid response of the disaster emergency relief and decision-making capability.Upon the full completion, the BeiDou Navigation Satellite System will provide more high-performance positioning, navigation, timing and short-message communication services for civil aviation, shipping, railways, finance, postal and other industries.IV. International Exchange and CooperationThe international exchange and cooperation for the BeiDou Navigation Satellite System will be carried out in an active and pragmatic way, which is in line withChina’s foreign policies, focusing on China's basic tasks and strategic objectives for the construction of navigation satellite systems, using the domestic and international markets and resources in a coordinated way. The international exchange and cooperation will be proceeded in a phased, focus-centered, non-discriminatory and selective approach in accordance with the overall development plan of China's navigation satellite system. It will be built upon the basis of equality, mutual benefit, mutual complementarity, peaceful utilization and mutual development and the generally accepted principles of the international laws.The BeiDou Navigation Satellite System adheres to the open and friendly attitude, and has already carried out extensive exchanges and consultation with the countries that have navigation satellite systems, to promote navigation satellite system compatibility and interoperability globally. Through the exchange and cooperation with countries that do not have a navigation satellite system, we also support their use of the existing resources globally and share the benefits of the satellite navigation development.China's international exchange and cooperation in the field of satellite navigation started in the 1990s. In nearly 20 years, various forms of activities have been carried out with extensive results.In 1994, under the framework of International Telecommunication Union(ITU),China started the BeiDou Navigation Satellite System frequency coordination activities. Satellite network information was submitted in accordance with the BeiDou system construction plan and progress. International frequency coordination has been carried out in a phased, step by step, focus-centered approach. China has actively participated bilateral frequency coordination activities with Europe, the UnitedStates and Russia, and has actively taken part in the World Radiocommunication Conference and the meetings of ITU study groups and working groups.China, as an important member of the International Committee on Global Navigation Satellite Systems (ICG), has participated in every ICG General Assembly Meeting and the ICG Providers Forum. In 2007, China became one of the four core providers designated by the organization. Focusing on compatibility and interoperability, China has carried out the extensive exchange and cooperation with the other navigation satellite systems in the world. The Technical Working Group (TWG) on compatibility and interoperability between BeiDou and Galileo was established. Until now, seven TWG meetings have been held.China actively participates, organizes and hosts international academic exchanges on satellite navigation, which include the American Institute of Navigation (ION) Conferences, the International Symposium on GPS/GNSS (ISGNSS), Munich Satellite Navigation Summit and other international conferences and forums. The China academic conferenceon satellite navigation is held annually, together with many other forums and seminars.China encourages and supports domestic research institutions, industrial enterprises, universities and social organizations, under the guidance of the government policy, to carry out international exchanges, coordination and cooperation activities with other countries and international organizations in the fields of the compatibility and interoperability, satellite navigation standards, coordinates frame, time reference, application development and scientific research. China has been actively engaged in international activities in terms of monitoring and assessment of open service for GNSS to promote the BeiDou Navigation Satellite System better serving the global users, and to promote the development of satellite navigation technology.ConclusionThe rapid development of the BeiDou Navigation Satellite System is attributedto China's reform and opening-up policy as well as the sustainable development of economy. As always, China will continue to promote the Global Navigation Satellite System construction and industrial development, to encourage the use of new satellite navigation technologies to provide new services, meeting the growing diversified needs of the people. By actively propelling international exchanges and cooperation, China will realize the compatibility and interoperability between the BeiDou Navigation Satellite System and other navigation satellite systems in the world. China will provide global customers with high performance and highly reliable positioning, navigation and timing services.The Launch Record of BeiDouNavigation Satellites·October 31, 2000, launch of 1st BeiDou navigation experiment satellite.·December 21, 2000, launch of 2nd BeiDou navigation experiment satellite.·May 25, 2003, launch of the 3rd BeiDou navigation experiment satellite.·February 3, 2007, launch of the 4th BeiDou navigation experiment satellite.·April 14, 2007, launch of the 1st BeiDou navigation satellite.·April 15, 2009, launch of the 2nd Beidou navigation satellite.·January 17, 2010, launch of the 3rd BeiDou navigation satellite.·June 2, 2010, launch of the 4th BeiDou navigation satellite.·August 1, 2010, launch of the 5th BeiDou navigation satellite.·November 1, 2010, launch of the 6th BeiDou navigation satellite. ·December 18, 2010, launch of the 7th BeiDou navigation satellite. ·April 10, 2011, launch of the 8th BeiDou navigation satellite. ·July 27, 2011, launch of the 9th BeiDou navigation satellite. ·December 2, 2011, launch of the 10th BeiDou navigation satellite.译文北斗定位前言卫星导航系统可以提供所有的时间，所有天气情况下用户在地球表面或近地空间的高精度定位、导航和授时服务。

全球定位系统的介绍英文

Introduction to the Global Positioning SystemChapter One: What is GPS?The Global Positioning System (GPS) is a location system based on a constellation of about 24 satellites orbiting the earth at altitudes of approximately 11,000 miles. GPS was developed by the United States Department of Defense (DOD), for its tremendous application as a military locating utility. The DOD's investment in GPS is immense. Billions and billions of dollars have been invested in creating this technology for military uses. However, over the past several years, GPS has proven to be a useful tool in non-military mapping applications as well.GPS satellites are orbited high enough to avoid the problems associated with land based systems, yet can provide accurate positioning 24 hours a day, anywhere in the world. Uncorrected positions determined from GPS satellite signals produce accuracies in the range of 50 to 100 meters. When using a technique called differential correction, users can get positions accurate to within 5 meters or less.Today, many industries are leveraging off the DOD's massive undertaking. As GPS units are becoming smaller and less expensive, there are an expanding number of applications for GPS. In transportation applications, GPS assists pilots and drivers in pinpointing their locations and avoiding collisions. Farmers can use GPS to guide equipment and control accurate distribution of fertilizers and other chemicals. Also，GPS is used for providing accurate locations and as a navigation tool for hikers, hunters and boaters.Many would argue that GPS has found its greatest utility in the field of Geographic Information Systems (GIS). With some consideration for error, GPS can provide any point on earth with a unique address (its precise location). A GIS is basically a descriptive database of the earth (or a specific part of the earth). GPS tells you that you are at point X,Y,Z while GIS tells you that X,Y,Z is an oak tree, or a spot in a stream with a pH level of 5.4. GPS tells us the "where". GIS tells us the "what". GPS/GIS is reshaping the way we locate, organize, analyze and map our resources.Chapter Two: Trilateration - How GPS Determines a Location In a nutshell, GPS is based on satellite ranging - calculating the distances between the receiver and the position of 3 or more satellites (4 or more if elevation is desired) and then applying some good old mathematics. Assuming the positions of the satellites are known, the location of the receiver can be calculated by determining the distance from each of the satellites to the receiver. GPS takes these 3 or more known references and measured distances and "triangulates" an additional position.As an example, assume that I have asked you to find me at a stationary position based upon a few clues which I am willing to give you. First, I tell you that I am exactly 10 miles away from your house. You would know I am somewhere on the perimeter of a sphere that has an origin as your house and a radius of 10 miles. With this information alone, you would have a difficult time to find me since there are an infinite number of locations on the perimeter of that sphere.Second, I tell you that I am also exactly 12 miles away from the ABC Grocery Store. Now you can define a second sphere with its origin at the store and a radius of 12 miles. You know that I am located somewhere in the space where the perimeters of these two spheres intersect - but there are still many possibilities to define my location.Adding additional spheres will further reduce the number of possible locations. In fact, a third origin and distance (I tell you am 8 miles away from the City Clock) narrows my position down to just 2 points. By adding one more sphere, you can pinpoint my exact location. Actually, the 4th sphere may not be necessary. One of the possibilities may not make sense, and therefore can be eliminated.For example, if you know I am above sea level, you can reject a point that has negative elevation. Mathematics and computers allow us to determine the correct point with only 3 satellites.Based on this example, you can see that you need to know the following information in order to compute your position:A)What is the precise location of three or more known points (GPS satellites)?B) What is the distance between the known points and the position of the GPSreceiver?Chapter Three: How the Current Locations of GPS Satellites are Determined GPS satellites are orbiting the Earth at an altitude of 11,000 miles. The DOD can predict the paths of the satellites vs. time with great accuracy. Furthermore, the satellites can be periodically adjusted by huge land-based radar systems. Therefore, the orbits, and thus the locations of the satellites, are known in advance. Today's GPS receivers store this orbit information for all of the GPS satellites in which is known as an almanac. Think of the almanac as a "bus schedule" advising you where each satellite will be at a particular time. Each GPS satellite continually broadcasts the almanac. Your GPS receiver will automatically collect this information and store it for future reference.The Department of Defense constantly monitors the orbit of the satellites looking for deviations from predicted values. Any deviations (caused by natural atmospheric phenomenon such as gravity), are known as ephemeris errors. When ephemeris errors are determined to exist for a satellite, the errors are sent back up to that satellite, which in turn broadcasts the errors as part of the standard message, supplying this information to the GPS receivers.By using the information from the almanac in conjunction with the ephemeris error data, the position of a GPS satellite can be very precisely determined for a given time.Chapter Four: Computing the Distance Between Your Position and the GPS SatellitesGPS determines distance between a GPS satellite and a GPS receiver by measuring the amount of time it takes a radio signal (the GPS signal) to travel from the satellite to the receiver. Radio waves travel at the speed of light, which is about 186,000 miles per second. So, if the amount of time it takes for the signal to travel from the satellite to the receiver is known, the distance from the satellite to the receiver (distance = speed x time) can be determined. If the exact time that the signal was transmitted and the exact time it was received are known, the signal's travel timecan be determined.In order to do this, the satellites and the receivers use very accurate clocks which are synchronized so that they generate the same code at exactly the same time. The code received from the satellite can be compared with the code generated by the receiver. By comparing the codes, the time difference between which the satellite generated and the receiver generated can be determined. This interval is the travel time of the code. Multiplying this travel time, in seconds, by 186,000 miles per second gives the distance from the receiver position to the satellite..Chapter Five: Four (4) Satellites to give 3D positionIn the previous example, you saw that it took only 3 measurements to "triangulate" a 3D position. However, GPS needs a 4th satellite to provide a 3D position. Why?Three measurements can be used to locate a point, assuming that the GPS receiver and satellite clocks are precisely and continually synchronized, thereby allowing the distance calculations to be accurately determined. Unfortunately, it is impossible to synchronize these two clocks, since the clocks in GPS receivers are not as accurate as the very precise and expensive atomic clocks in the satellites. The GPS signal speed traveling from the satellite to the receiver is very fast, so if the two clocks are not synchronized, even if only a small part, the determined position data may be considerably distorted.The atomic clocks on aboard keep their time at a very high degree of accuracy. However, there will always be a slight variation in clock rates from satellite to satellite. Close monitoring of the clock of each satellite from the ground permits the control station to insert a message in the signal of each satellite which precisely describes the drift rate of that satellite's clock. The insertion of the drift rate effectively synchronizes all of the GPS satellite clocks.The same procedure cannot be applied to the clock in GPS receiver. Therefore, the fourth variable (in addition to x, y and z)time must be determined in order to calculate a precise location. Mathematically, to solve for four unknowns (x,y,z, and t), there must requir four equations. In determining GPS positions, the four equations arerepresented by signals from four different satellites.Chapter Six: The GPS Error BudgetThe GPS system has been designed to be as nearly accurate as possible. However, there are still errors. Added together, these errors can cause a deviation of +/- 50 -100 meters from the actual GPS receiver position. There are several sources for these errors, the most significant of which are discussed as bellows:Atmospheric ConditionThe ionosphere and troposphere both refract the GPS signals. This causes the speed of the GPS signal in the ionosphere and troposphere to be different from the speed of the GPS signal in space. Therefore, the distance calculated from "Signal Speed x Time" will be different from the portion of the GPS signal path that passes through the ionosphere and troposphere and for the portion that passes through space.As mentioned earlier, GPS signals contain information about ephemeris (orbital position) errors, and about the rate of clock drift for the broadcasting satellite. The data concerning ephemeris errors may not exactly model the true satellite motion or the exact rate of clock drift. Distortion of the signal by measurement noise can further increase positional error. The disparity in ephemeris data can introduce 1-5 meters of positional error, clock drift disparity can introduce 0-1.5 meters of positional error and measurement noise can introduce 0-10 meters of positional error.Ephemeris errors should not be confused with Selective Availability (SA), which is the intentional alteration of the time and ephemeris signal by the Department of Defense.GPS signal bouncing off a reflective surface prior to reaching the GPS receiver antenna is referred to as multipath. Because it is difficult to completely correct multipath error, even in high precision GPS units, multipath error is a serious concern to the GPS user.Chapter Seven: Measuring GPS AccuracyAs discussed above, there are several external sources which introduce errorsinto a GPS position. While the errors discussed above always affect accuracy, another major factor in determining positional accuracy is the alignment or geometry of the group of satellites (constellation) from which signals are being received. The geometry of the constellation is evaluated for several factors, all of which fall into the category of Dilution Of Precision, or DOP.DOP is an indicator of the quality of the geometry of the satellite constellation. computed position may be derrerent, depending on which satellites you use for the measurement. Different satellite geometries can magnify or reduce the errors in the budget described above. A greater angle between the satellites lowers the DOP, and provides a better measurement. A higher DOP indicates poor satellite geometry, and an inferior measurement configuration.Some GPS receivers can analyze the positions of the satellites available, based upon the almanac, and choose those satellites with the best geometry in order to make the DOP as low as possible. Another important GPS receiver feature is to be able to ignore or eliminate GPS readings with DOP values that exceed user-defined limits. Other GPS receivers may have the ability to use all of the satellites in view, thus minimizing the DOP as much as possible.。

GPS全球定位系统中英文资料对照外文翻译文献

毕业论文GPS全球定位系统中英文资料对照外文翻译文献Summarizing The Global Positioning SystemAbstract:Global Positioning System is based on the background of the United States Department of Defense.It is designed,invested,developed,and operated by the United States Department of Defense ,GPS is a satellite-based positioning and time transfering GPS positioning function has a wide range of applications in the modern measurement and a more modern building.GPS-RTK technology is also widely used in modernization building, and now GPS has also been shown to be an important civilian communities of interest, and increasingly wide range of applicated.Keyword:GPS,Locating，RTK，Lay out，Survey1.BackgroundThe 50s, the former U.S.S.R has not launched humanities first artificial earth satellite, the American scientists in along its track research in, had discovered the Doppler shift phenomenon, and has facilitated Doppler satellite navigation posi- tioning system completing using this principle, has obtained the enormous success in the military and the civi aspect, was in a navigation localization history leap, our country once has also introduced many Doppler receiver, applied to the island association measured, the Earth explored and so on the applied to the island association measured, the Earth explored and so on the domain. But because Doppler satellite orbit highly low, signal-carrier frequency low, the track precision enhances with difficulty, causes the pointing accuracy lowly, satisfies the geodetic survey or the project survey request, is more impossible to use in the astronomy Earth dynamics research. In order to enhance the satellite positioning the precision,US started from 1973 to prepare for construction global positioning system GPS (Global Positioning System).After has entered the plan proof, the system test stage,started in 1989 to launch the official work satellite,and completely completed in 1994, investment use. The GPS system spaceartially is composed by twenty one satellites, evenly distributes in six orbit, the ground level is 20,000 Kilometers, the inclination of orbit is 55, the flat heart rate approximately is 0, the week contract is 12 hours, the satellite to the earth launching two wave bands intelligence signals,the intelligence signal frequency respectively is 1575.442 megacycles per second (the L2 wave band), on the satellite has installed the precision very high atomic clock, guarantees the frequency the stability, modulates in the carrier has the expression satellite position the broadcast star experience, use in the range finder C/A code and P yard, as well ad other system information, can in the global scope, to willfully multi-user provide the high accuracy, all-weather, is continual, real-time three dimensional measures fast, the three dimensional localization and the time service.The GPS system control section by is located in the American foundations of the states 5 monitoring stations to be composed, these stand did not ask breaks Carries on the observation to GPS satellite, and will calculate and the forecast information by the infusion stands renews to the satellite information.The GPS system user is extremely covert, it is one kind of one-way system,the user only receives but does not need the transmitting message, and therefore user' s quantity also is not limited. Although GPS is the unification starts is, but very quantity also is not limited. Although GPS recei ver and processing software emerge in abundance. At present the receiver which appears in the Chinese market mainly has ROGUE,ASHTECH, TRIMBLE, LEICA, SOKKIA, TOPCON and so on.. Can carry on the observation to two frequencies the receiver to be called the double frequency receiver, only can carryon the observation to a frequency the receiver to become the inference. Says regarding the mapping user, GPS has caused the revolutionary change in the mapping domain, at present, in the scope several thousand kilometers controls network, in the precision from hundred to the millimeter level localization, generally all GPS took the first choice method, is day by day mature along wi th the RTK technology, GPS started to decimeter and even a centimeter level layout, domain seepage and so on high accuracy dynamic localization.The international GPS geodetic survey served IGS with Earth dynamics from 1992, has established many data storage and the processing center in the whole world, year to year observed a station with hundred, our country has also set up Shanghai Y u Shan, Wuhan, Xian, Taiwan and so on many year to year measuring platforms station, these stations observation data passed on every day through the internet net to US' S data storage center, IGS also nearly real-time synthesizes various data processing center the result, and the participant international earth rotation served the IERS global coordinatesreference system maintenance and the earth rotation parameter issue. The user also may free on-line obtain product and so on observation data and precise star experience from internet.The GPS system real-time navigation pointing is very high,US hasimplemented the so-called SA policy in 1992, namely reduces the broadcaststar to undergo the star posi tion precision, reduces the star clock to change thepositive number the precision, adds on the high frequency vibration to thesatellite datum frequency (to cause false distance measuring accuracy to reducewith phase ), latter has implemented the A-S policy, soon P yard change is Y yardnamely further limi ts to the precise false distance survey, but American military and special permission user not these polices influences, but US in order to obtain the bigger commercial interest, these policy ends are cancelled.2.GPS localization principalThe GPS receiver may receive and use in the time service accurately to the nanosecond level time information; will use in to forecast the future for several months the satellite to locate the summary position forecast star experience; Uses in calculates when the localization to need the satelli te coordinates the broadcast star experience, the precision is (each satellite is different several meter to several dozens meters~changes as necessary); As well as GPS system information, like satellite condition and so on.The GPS receiver may obtain the satellite sign to the code to the receiver distance, because includes the receiver satellite clock the error and the atmosphere propagated error, therefore is called the false distance. The false distance obtains which to the OA code is called the UA code false distance, the precision approximately is about 20 meters, obtains the false distance to P yard to be called P yard false distance, the precision approximately is about 2 meters.The GPS receiver to the satellite signal which receives, carries on the decoding or uses other technologies, will modulate after the carrier the information removes, will be allowed to restore the carrier. Strict says, the carrier phase should be called the carrier beat frequency phase, it is receives produces the Doppler shift influence satellite signal carrier phase and receiver this machine vibration difference of the signal phase. Generally experience Yuan time which determined in the receiver clock surveyed,maintains to the satellite signal track under, may record the phase change value, but starts time the observation receiver and the satellite oscillator phase change value is does not know, namely misty degree of whole week, only can calculate in the data processing as the parameter solution. Phase observation value precision high to millimeter, but the premise is solves misty degree of whole week, therefore only has when the relative localization, and has a section continuously observes the value can use the phase observation value, but must achieve meters down to themillimeter level also only to be able to use the phase observation value.According to the locate mode, the GPS localization divides into the simple point localization and the relative localization (difference localization). The simple point localization is according to a receiver observation data determined the receiver position the way, it only can use the false distance view survey, may use in Chef Chuan and so on the summary navigation localization. The relative localization (difference localization) is according to two above receivers observation data determined between the observation point the relative position method, it already may use the false distance view survey also to be possible to use the phase view survey, the geodetic surveyor the project survey should use the phase observation value to carryon the relative localization. Has contained the satellite and receiver ZhongChai, the atmospheric dissemination in the GPS view survey retards, error and so on multipart effect, when localization error the influence, when carries on the relative localization the majority of public errors are counterbalanced or weaken, therefore the pointing accuracy greatly will enhance, the double frequency receiver will be allowed to act according to two frequencies in the view survey counterbalance atmosphere the ionosphere-path error main part, will request high in the precision, between the receiver the distance wi11 be farther when (atmosphere will have obvious difference), will be supposed to select the double frequency receiver.When localization observation, if the receiver is opposite to the earths surface movement, then is called the dynamic localization, like uses in summary navigation localization the and so on Chef Chuan precision is 30-100 meter false distance simple point localization, either uses in the city vehicles navigation localization rice level precision false distance difference localization(RTK), the real-time differencelocalization needs the data chain real-time transmits two or many stations observation data calculates together.When localization observation, if the receiver is opposite to the earths surface static, then is called the static localization, when carries on controls the net observes, generally selects this method by several receivers also to observe, it can maximum limit display GPS the pointing accuracy,special-purpose Yu Zheizhong the goal receiver is called the earth receiver,is in the receiver a performance best kind. At present, GPS already could achieve the earths crust performance observation the precision request, IGS year to year the measuring platform already can constitute millimeter level the global coordinates frame.3.RTK technologiesThe conventional GPS measuring technique, like the static state, the fast static state , the dynamic survey all~eed afterwards to carryon the solution to calculate can obtain a centimeter level the precision, but RTK is can real-time obtain the centimeter level pointing accuracy in the open country the measuring technique, it has used the carrier phase dynamic real-time difference (Real-timekinematics) the method, is the GPS application significant milestone, its appearance for the project layout, the terrain mapping, each kind of control survey has brought the new dawn, enormously enhanced the field operation work efficiency.The high accuracy GPS survey must use the carrier phase observation value,the RTK localization technology, it can real-time provide in assigns in the coordinate system the three dimensional localization result, and achieves the centimeter level precision. Under the RTK work pattern, the datum stands through the data chain transmi ts together its observation value and the survey station coordinates information for the mobile station. Mobile stands not only receives the data through the data link which stands from the datum, but also must gather the GPS observation data, and composes the difference observation value in the system to carryon the real-time processing, simultaneously produces the centimeter level localization result, a lasted. The mobile station may be at the static condition, also may be at the state of motion; May first carryon the initialization after the fixed point to enter the dynamic work again,also may under the dynamic condition directly opening machine,and completes the week fuzziness search solution under the dynamic environment. After end knows the number solution to be fixed, then carries on each calendar Yuan real-time processing, so long as can maintain four above satellites phases observation value the track and the essential geometric figure ,then the mobile station may produce the centimeter level localization result as necessary.The RTK technology key lies in the data processing technology and the data transmission technology, when the RTK localization requests the datum station receiver real-time the observation data (false distance observation value, phase observation value) and the know data transmission for the mobile station receive, the data quantity quite big, generally all requests 9,600 bauds rate, this in on radio is not difficult to realize.4.The application of RTK(1)Each kind of control surveyThe traditional geodetic survey, the project control survey uses the triangular net, the line-network method executes measured, not only requires a lot of work time-consuming, request Indivisibility, moreover the precision distribution non-uniformity, also at the field operation did not know how the precision, does use conventional the GPS static state survey, the fast static state, the false dynamic method, survey in the process at field operation not to be able real-time to know the pointing accuracy, after if surveys completes, after returns to house processing to discover the precision does no t gather the request, but also must return measured, but uses RTK to carryon the control survey, can real-time know the pointing accuracy, if the fruits and cakes position precision request has satisfied, the user was allowed to stop observing, how moreover knew the observation quality, This may greatly enhance the work efficiency. If uses in the road control survey RTK,electronic circuit control survey, the hydraulic engineering control survey, the geodetic survey, then not only may greatly reducethe manpower intensi ty, the economical expense, moreover greatly enhances the working efficiency,measured a control point may complete in several minutes even several seconds.(2)Terrain mappingIn the past measured when topographic diagram generally first must in measure area establishment chart root control point, then on chart root control point top carriage entire station meter or altazimuth coordination small flat panel mapping, now develops the field operation with the entire station meter and the electronic hand coordination thing code, uses big scale mapping software to carryon the mapping, even develops recent field operation electron dull mapping and so on, all requests in the survey station to measure all around terrain landform and so on department point, these points all wi th survey station indivisibility, moreover generally requests at least 2-3 person to operate, needs when puts together the chart once the precision not to gather the request also to obtain the field operation to return measured,when now uses RTK, only needs a person to carry the instrument in on the terrain landform department point dull 12 second kinds which must measure, and simultaneously inputs the characteristic code, through hand book may real-time know the position precision, after measured a region returns to in the room, may output the topographic diagram by the specialized software connection which requests, like this uses RTK only to need a person to operate,does not request a between indi visibi Ii ty, greatly enhanced the working efficiency, uses the RTK coordination electron hand book to be allowed to survey each kind of topographic diagram, I ike the ordinary mapping, the track，line strip the shape topographic diagram surveying, road pipeline topographic diagram surveying, coordinates the depth-finding device to be allowed to use in to measure the reservoir topographic diagram, Navigation sea mapping and so on.(3)LayoutLayout surveys an application branch, it request through the certain method to use the certain instrument the spot position which artificial designs in really for to demarcate, in the past used the convention layout the method very many, like the altazimuth junction met layout, when the ent ire 50 station meter and so on, generally layout a design position, often needed the back and forth bile target, moreover took 2-3 person to operate, simultaneously also requested the indivisibility situation in the process to be good, in the production application the efficiency was not very high, sometimes layout encountered the difficult situation to be able to draw support fromYu Hindu the methodto layout. Sometimes, if uses the RTK technology layout, only must the spot position coordinates which designs input to the electron hand, is carrying the GPS receiver, it can remind you to walk to want to layout a position, both rapid and convenient, because GPS is comes directly through the coordinates layout,the precision is very high, thus can greatly enhance efficiency, also only needs a person to operate.5. The application of GPSGPS offers for military and makes a reservation and sets up accurately at first, it is still controlled by the American military so far. Military GPS products is it confirm and follow in field advancing soldering and coordinating of equipment in to used for mainly, the gunship for the sea navigates, offers the position and navigation information for military aircraft.(1) The GPS system use is extensivelyAt present, application, GPS of system very extensive already, we can use GPS signal can carryon sea, empty and navigation of land, the guidance of the guided missile, earth measurement and accurate localization of project measurement., transmission of time and measurement of the speed,etc.For survey and draw field,GPS satellite fix technology is it set up nationwide earth measurement of high accuracy control network to use for already, determine global dynamic parameter of earth;Used for setting up land marine earth measurement datum, unite and examines and surveys and draws in the ocean the high-accuracy island land;Used for moni toring plate motion state of the earth and the earths crust deformation;Used in project measure,is it set up city and project control main means of network to become For determine Aero-Space photograph camera position in the twinkling of an eye, realize for a small amount of ground control or there is no aerial survey controlled in region to become and pursue fast, technical revolution causing the geographical information system,global environmental remote to follow their monitor.A lot of commerce and government organs use GPS equipment to follow their vehicle position;This generally needs to draw support fromwireless communication technology.Some GPS receiver integrated radio, radio telephone move data terminal is it meets need, motorcade of management to come.(2) Appearance of the resource environment of pluralistic spaceAt present, GPS, GLONASS, INMARSAT waits for the system to all possess and navigate to orient the function, formed the pluralistic room resource environment. This pluralistic space environment ,has impelled and fumed a piece of common tactics internationally and folly, namely on one hand fully utilize the existing system, on the other hand prepare to establish folk GNSS system actively ,by the tome around the2010,GNSS folk system build our purely, the woke world form the tendency that GPS/GLONASS/GNSS stood like the legs of a tripod, could get rid of the reliance on the single system fundamentally, form owning in common, security resource environment which world shares of worlk.World can is it is it use realm at most as single navigation means to navigate satelli te to enter. This international and folk strategy, there id influence and force U.S.A to use the policy to make more omen adjustment to its GPS converselu. Inaword , because of the establishment of the resource environment of pluralistic space ,have created an unprecedented gapped international environment for the development and application of GPS.(3) Develop gaps industryGPS Will form industrialization like the automobile, wireless communication at present in the future, US>A strengthen wide area systematic WAAS (namely wide area is it revise date chain transfer to already, it make geostationary satellite it have C? A yards of function too, form wide area the GPS strengthen system of) plan international standard of developing into of. Some units produce car-mounted GPS system too at present in our country.For GPS industry of developing our country, already China GPS project centrehas been established in Wuhan.全球定位系统概述摘要：全球定位系统是以美国国防为背景，由美国国防部设计、投资、开发、和运行的。

gps的主要功能和应用英语作文

gps的主要功能和应用英语作文## Global Positioning System (GPS)。

The Global Positioning System (GPS) is a satellite-based navigation system that provides location and time information to users on Earth. It is a constellation of 24 to 32 Medium Earth Orbit (MEO) satellites that orbit the Earth. The system was developed by the United States Department of Defense and is maintained by the United States Air Force.The GPS system consists of three segments:Space segment: The space segment consists of the 24 to 32 satellites that orbit the Earth. The satellites are arranged in six orbital planes, each with four satellites. The satellites are constantly transmitting signals that contain their location and time information.Control segment: The control segment consists of amaster control station and a network of ground stations. The master control station is located at Schriever Air Force Base in Colorado. The ground stations are located around the world and are used to monitor the satellites and to update their orbits.User segment: The user segment consists of the receivers that users use to receive the signals from the satellites. Receivers can be found in a variety of devices, including smartphones, cars, and airplanes.The GPS system works by measuring the time it takes for a signal to travel from a satellite to a receiver. The receiver then uses this information to calculate its distance from the satellite. By measuring the time it takes for signals to travel from multiple satellites, the receiver can determine its three-dimensional position.The GPS system is used for a wide variety of applications, including:Navigation: The GPS system is used for navigation in avariety of applications, including driving, hiking, and boating.Surveying: The GPS system is used for surveying to measure the location of points on the Earth's surface.Tracking: The GPS system is used for tracking to track the location of people, animals, and objects.Timing: The GPS system is used for timing to provide accurate time information.### GPS主要功能和应用。

外文翻译---GPS全球卫星定位系统

外文翻译---GPS全球卫星定位系统英文文献The Global Positioning SystemThe global Positioning System (GPS) is revolutionizing surveying technology, Like its predecessor , the TEANSIT Doppler system, GPS shifts the scene of surveying operations from ground-to-ground measurements to ground-to-sky , with obvious implications : intervisibility of marks is no longer a criteion for their location ; operations are possible in nearly all kinds of weather and be performed during day or night ; and the skills required to utilise the technology are different both in field operations and data processing . But GPS is not merely a replacement for TRANSIT . The simultaneous visibility of multiple satellites allows effective cancellation of the major sources of error in satellite observations , with the result that with GPS, relative positioning accuracies of one part per million(ppm) or better over distances from one kilometer to thousands of kilometers are possible . This means that GPS can compete with terrestrial techniques over short distances, and can achieve more accurate results in less time than TRANSIT observations over longer distances .GPS was designed primarily as a navigation system, to satisfy both military and civilian needs for real-time positioning. This positioning is accomplished through the use of coded information, essentially clever timing signals, transmitted by the satellites. Each GPS satellite transmits a unique signal on two L-band frequencies: A at 1575.42 MHz and B at 1227.60 MHz(equivalent to wavelengths of approximately 19 and 24 cm, respectively).The satellite signals consist of the L-band carrier waves modulated with a "Standard" or S code (formerly called the C/A code),a "Precise" or P code and a Navigation Message containing, amongst other things ,the coordinates of the satellites as functions of time---the "Broadcast Ephemerides". The S code which is intended mainly for civilian use , yields a range measurement precision of about 10 meter, The navigation service provided by this code is referred to as the Standard Positioning Service, The p code is intended for military and selected civilian useonly and yields a measurement precision of about 1 meter, The navigation service provided by the P code is therefore referred to as the Precise Positioning Service (PPS) Although both codes can be used for surveying , a more accurate method is to measure the phase of the carrier signal , For this reason , we will not discuss the detailed characteristics of the codes in this monograph .There are currently eight usable satellites in orbit. These are the experimental, ”Block 1” satellites, which will be progressively replaced as the “block 2”, operational satellites are placed into orbit beginning in 1986.By 1989 the system should be complete, with 18 satellites in six orbital planes----at about 20200 km altitude, allowing for simultaneous visibility of at least four satellites at any time of day almost anywhere in the world. The present constellation of satellites is configured to provide the most favorable geometry for testing the system over North America.As it happens, the observation geometry is equally favorable in Australia, and it is possible now to obtain surveying accuracies equal to those obtainable when the system is fully configured, but only for about six hours per day, At the time of writing (November 1985),the period of maximum mutual visibility of the satellites in eastern Australia is between 6 pm and mid-night local time The period regresses by 4minutes per day (or 2 hours per month), returning to the same times a year from now. This period of useful visibility will increase as additional satellites are launched from late 1985.As with TRANSIT , much higher accuracies are obtained in relative positioning from observations made simultaneously at two observing stations. Consequently , unless otherwise indicated , all discussion concerning data acquisition and processing will assume a two----receiver configuration. This is often referred to as the differential mode. The position differences so determined constitute the baseline vector or simply the baseline between the points occupied by two receivers .All satellite positioning systems provide ground coordinates of a receiver (or the baseline vector between a pair of receivers) in an earth—centered coordinatesystem, The orientation of the system is determined by the tabulated coordinates or ephemeredes of the GPS satellites. In order to relate coordinates determined by GPS surveying to the local geodetic datum a transformation relationship needs to be established.The following factors influence the final positioning accuracy obtainable with GPS:(1)The precision of the measurement and the receiver---satellitegeometry.(2)The measurement processing technique adopted.(3)The accuracy with which atmospheric and ionospheric effects can bemodeled.(4)The accuracy of the satellites ephemeredes.Each of these factor is discussed briefly in the next three sections.GPS Measurement Types. GPS measurement can be made using either the carrier signal or the codes. Code measurements are called pseudo-ranges and can be based on either the P code or the S code.Knowledge of the properties of each of these types of measurements is necessary for understanding and evaluating GPS instruments.Pseudo-ranges are the simplest to visualize geometrically , as they are essentially a measurement of distance contaminated by clock errors. Throughout this monograph, we use the terms clock , frequency standard and oscillator to denote the same thing , namely , a device for precisely measuring a time interval. When four satellites are observed simultaneously , it is possible to determine the three-dimensional position of the ground receiver, and the receiver clock offset, at a single epoch . This is simply resection by distance, in surveying terminology , with the satellites serving as the control station, As with the resection technique, the precision is a function of the geometry of the receiver in relation to the four visible satellites. The best geometry would be when the satellites are in each of the four quadrants and each at an elevation angle of 40°--70°above the horizon. However , pseudo-range measurements are not nearly as precise as phasemeasurements of the carrier wave itself . In order to achieve position accuracies of 10 meter from P code measurements or 100 meter from S code measurements ( adequate for navigation ) , it was only necessary to design a code structure which allowed metre level measurement precision . Morever , the more precise P code will likely be encrypted , and may therefore not be available for non-military use , when the system becomes fully operational in 1989 . An additional impediment to accueate pseudo-ranging arises from multipath effects , that is the tendency of some fraction of the satellite signal to reach the receiver antenna via reflection off the ground or other surfaces . The size and signature of multipath effects depend on antenna design and height of the antenna above ground but probably cannot be reduced below a few decimeters with practical configurations .Carrier phase can be determined from the code-modulated signal either by using the code or other techniques . The L1 signal , which has both P code and S code modulation , can thus be tracked with S or P code receivers or with codeless receivers . The L2 signal , useful for removing ionospheric effects for very precise applications (< 2 ppm for relative positioning ) , has no S code modulation , so that receivers for these applications must either have P code capability or operate without code .It is also possible to track the phase of the 10.23 MHz P code transition signal or P code sub-carrier without knowledge of the codes . The long wavelength ( approximately 30 meter ) of this signal compared with the L-band carrier allows relatively easy resolution of the integer-cycle ambiguity , producing in effect a pseudo-range measurement . However , the long wavelength makes the measurements more susceptible to multipath effects , roughly to the same degree as pseudo-range measurements .中文文献GPS全球卫星定位系统全球性定位系统(GPS) 是一种革命化勘测技术, 像它的前辈, TRANSIT 子午仪多普勒系统（TRANSIT）, GPS 转移勘测的操作场面从地地测量到地面对天空测量, 以明显的涵义: 几乎所有是操作都可以在各种天气和昼夜完成；在野外观测和数据处理中所需要的技能和技术是不同的。

GPS全球定位技术外文翻译文献

GPS全球定位技术外文翻译文献GPS全球定位技术外文翻译文献(文档含中英文对照即英文原文和中文翻译)Global Positioning System (GPS)Donald Pfost and William Casady, Extension Agricultural Engineers Kent Shannon, Associate Director of the Missouri Precision AgricultureCenter University of Missouri-ColumbiaRange determination factorsEach GPS satellite continuously broadcasts two radio signals on separate L-band frequencies (the L-band is from 1,000 to 2,000 MHz). The L1 signal (transmitted at 1575.42 MHz) carries two codes, a Coarse/Acquisition (C/A) code and a Precision (P) code. The L2 signal (transmitted at 1227.60 MHz) carries only the P code, which is encrypted so only the military and other “authorized” receivers can interpret i t. The use of both the L1 and L2 signals and their P codes produces what is called the Precise Positioning Service (PPS) and is available to the U.S. and allied military, U.S. government agencies and authorized civilian users. The system available for all civilian use accesses only the L1signal and the C/A code and is known as the Standard Positioning Service.GPS technologyGlobal Positioning System (GPS) receivers provide a method for determining location anywhere on the earth. Accurate, automated position tracking with GPS receivers allows farmers and agricultural service providers to automatically record data and apply variable rates of inputs to smaller areas within larger fieldsA GPS receiver can be compared with a simple AM or FM radio. A GPS receive r “listens” for the signals that are broadcast from the satellites of the United States Department of Defense (DOD) Global Positioning System. Orbiting around the earth at an altitude of 12,550 miles, these satellites are in predictable locations; hence, we refer to the system of satellites as the GPS constellation.Each satellite broadcasts almanac information containing the position of all satellites in the constellation. GPS receivers use the almanac to determine the position of the satellites. Minor variations in the orbits of the satellites occur due to gravitational forces from the sun and the moon. The DOD continuously monitors the satellites and adjusts the almanac information to represent the actual orbits of the satellites.The broadcast signals also contain a precisely timed predictable code thata GPS receiver can use to deter-mine how long the signal required to reach the receiver. A microprocessor within a GPS receiver uses these delays and the position of the satellite to calculate the distance to each satellite, and then uses this information to determine location through triangulation.Triangulation is a mathematical method for locating points on a plane in three-dimensional space. If the distances to each of three satellites and your approximate location on the earth are known, the GPS receiver can calculate its terrestrial position. If information from four satellites is available, elevation can also be determined.AccuracyThe accuracy obtained generally depends on five factors1) proper installation2) the degree of technology used in the receiver3) the number and location of satellites4) errors introduced by selective availability(SA), atmospheric conditions, the troposphere, the ionosphere, and multipathing 一radio signals bouncing off objects in the area5) differential corrections.InstallationGPS antennas should be mounted on the centerline of a combine, tractor or truck and above any part of the machinery that might obstruct a line of sight to a satellite. If the cab is centered and the top of the cab is above other portions of the machine, a cab-top mounting maybe the best location. However, on a steep side slope, a high mounting point will result in an error in position calculation due to the offset in horizontal position.GPS and DGPS receivers may have separate antennas but usually there will be a combination antenna so that both are centered at the same location. A delay of several seconds often occurs in agricultural applications such as yield monitoring, spraying and fertilizer application.Example: If the antenna on a sprayer traveling 10 mph is mounted 30 ft ahead of the booms and a rate change at the controller is effected at the boom two seconds later, the rate change will occur when the booms reach the location of the antenna where the change was made. At any other ground speed, the rate change at the booms will not occur at the same location as the controller. A time adjustment mustusually be factored into the system to compensate for time delays in sensing or product application.Electrical interference can result from electrical storms, power lines, 2-way radios, nearby radio transmitters, electricmotors, microwave towers, cellular phones, vehicular electrical equipment such as alternators and ignition systems on spark-ignition engines and other sources. Changing the position of the antenna or adding noise suppression kits may reduce interference problems from alternators and ignition systems. Follow the instructions for installation of the GPS equipment, making sure that all connections are tight.TechnologyLow-cost receivers receive signals from one satellite at a time and require more time to determine the location than a receiver capable of receiving four signals simultaneously. Usually, seven to 10 satellites are in view at any one time and more sophisticated receivers will produce the most accurate location.Reacquisition time is the time it takes to get an accurate position fix aftera short-time loss of satellite signals; this may occur for a variety of reasons, including traveling near trees or buildings and losing the …line of sight? to satellites. Reacquisition time is important for most agricultural applications and especially for guidance with applicators and aircraft. New technology in GPS receivers has shortened reacquisition time. Receivers that can track 8-12 satellites are less susceptible to acquisition loss.Satellite constellationsUsing triangulation to calculate position, small errors in distance can cause large errors in position. The error in calculating position through triangulation increases when the satellites are close together. The best accuracy is produced when the receiver can pick up signals from many widely dispersed satellites (Figure 1).Selective availability and other errors Selective availability and other errors To prevent an enemyfrom using GPS satellite signals for determining locations on earth, the DOD“scrambles” the signals sufficiently to introduce an error of about 100 meters in an uncorrected location calculation. The term for th is is “selective availability” (SA). Atmospheric, tropospheric and ionospheric conditions, however, also cause distortions or errors in calculating distance; natural errors due to these conditions are not easily or reliably predicted. Hence, even in the absence of SA, differential corrections will still be required to accurately calculate position.Multipathing, the phenomenon that creates distorted television signals is caused by signals that bounce off of other objects before reaching the antenna (Figure 2). Multipathing cannot be corrected by differential correctionsDifferential correctionsStationary GPS receivers are used to calculate the total error due to SA, variable atmospheric conditions and other factors. The concept is simple. A stationary receiver always has a known location; because the actual positions of the satellite and the receiver are known the true range (distance) is known. The distance calculated by the receiver using the broadcast signals is known as the pseudorange, which is generally in error due to the combined sources of all errors. The difference between the true range and the pseudorange is the error and is known as the differential correction (Figure 3).Differential correction data can be purchased and used at a later time in a process known as post processing to correct the errors in recorded data. However, the most common approach is to connect a differential corrections receiver to a GPS receiver to provide real-time corrections (Figure 4).Many units incorporate GPS receivers and differentialcorrections receivers into the same unit. These are often referred to as differentially-corrected GPS (DGPS) receivers. Differential corrections signals are single path from satellite to receiver Satellite-based correction signals available from the Coast Guard or Army Corps of Engineers and through commercial sources, which, for a fee, will provide signals from a satellite or a land-based tower. Where these sources aren?t a vailable or for special applications, a private differential corrections source can be installed.Some of the newer DGPS receivers combine the capability of receiving differential signals from both the Coast Guard beacons and from a satellite service. Refer to Table 1 for a comparison of features of Coast Guard and satellite-based differential corrections sources.Coast Guard signalsThe Coast Guard signals are broadcast in the frequency range of 285-325 kHz (just below the usual AM-radio band) where radio waves travel as ground waves and are not limited to line-of-sight reception like FM-radio stations.The signals are series of pulses similar to those GPS satellites. Referred to as Minimum Shift Keying modulation, the signal is less sensitive to electrical interference and noise than AM-radios.Missouri has free access to correction signals from Coast Guard beacons located near St. Louis (@322 KHz), Kansas City (@ 305 KHz), Tulsa (@ 299KHz), Rock Island (@ 311 KHz), Memphis (@ 310KHz) and Omaha (@298 KHz).The range of the Coast Guard beacons is approximately 150 miles in good weather (electrical storms cause interference). Accuracy decreases with distance from the transmitter. This service is expected to become the choice of many agriculturalusers, especially in Missouri where several signals are available.A disadvantage of the Coast Guard differential corrections signal is the rate at which the beacon transmits or repeats messages. Most Coast Guard sites broadcast at 200 bits per second. At this broad-cast rate, the age of a satellite?s differential correction can be as old as four seconds. For some applications, such as guidance, this update rate may be unacceptable. For guidance applications, update rates of two to ten times per second may be required.Typical Coast Guard beacon receivers have two channels. One channel receives the differential correction and the other is searching for thebest incoming signal. This helps to ensure against loss of a DGPS signal if at least two beacons are within range.Satellite-based correction signals For the user, one of the simplest types of differential corrections signals is transmitted from a geostationary satellite. Companies such as Omni star Accqpoint and Racal provide this service.The typical annual user?s fee ranges from $500 to $800. The correction signal is available throughout most of North America. The accuracy of high quality receivers is generally considered to range from one to three meters RMS (refer to accuracy table on p. 5).Interference from man-made sources is minimal.Satellite-based signals may have an advantage for operation around trees and buildings since the satellite is nearly overhead at most locations and within the DGPS receiver?s line-of-sight.Land-based correction signals Several commercial land-based correction signal services are also available for a fee. Some companies put up their own transmitters to broadcast correction signals; these include SatLoc, Mobile Data and CSI.Some commercial service providers piggy back correction signals onto commercial FM radio station transmitters. These sub-carriers include Pinpoint Communications, DCI and others.Private GPS receiver and radio transmitter GPS users not covered by Coast Guard or com-mercial sources ofdifferential corrections can install a stationary receiver and transmitter to provide theirown differential corrections source. Few users in Missouri will choose to buy and install their own fixed GPS receiver and transmitter since the Midwest has other choices available.Cost vs. accuracyThe accuracy attainable with GPS depends partly on how much you are willing to spend, ranging from approximately $100 to $100,000. A low-cost (from $100 to $500) GPS receiver without DGPS capability may be sufficiently accurate for some crop scouting applications, for navigating highways or for locating your favorite fishing spot on a lake. The RMS horizontal accuracy may be about 50 yards.The cost for a basic DGPS receiver suitable for most agricultural applications is about $3,000 to$5,000 and provides RMS accuracy of at least three meters with a typical accuracy of one meter, which is sufficient for yield monitoring and grid soil sampling.If you need a GPS receiver for guidance (for spraying, fertilizer application, etc.), the cost may be up to $25,000. Such systems provide accuracy down to a few inches. Since sprayers and fertilizer spreaders can travel fairly quickly, lower quality GPS equipment may not update position quickly enough to be used for guidance or control, although GPS systems with high update rates and accuracies in the range of one foot or less are becomingavailable at lower prices.The annual subscription cost for some differential correction services varies with the level of service (accuracy). Some providers offer three levels of ser- vice, e.g., one provider has a premium service for better than 1meter accuracy, intermediate service for accuracies in the range of 5 meters and a basic service for accuracies in the range of 10 meters. Typical approximate costs may be $600, $250 and $75 per year, respectively, depending on the level of service.Coordinate systemsSeveral coordinate systems are in use for mapping and may cause problems with compatibility between software systems. Users frequently need to transform position data into a plane (flat) coordinate system, either to merge them with another data set, to plot a map of the GPS results, or to perform further calculations for such parameters as area, distance or direction(plane coordinate systems are usually easier to work with than geodetic coordinates). When using data and maps from several sources, coordinates must be based on the same datum. The coordinate system differences, which are caused by a different reference frame, ellipsoid and data adjustment, are significant (up to several hundred meters) and cannot be ignored.Several commercially-available software programs produced by well-known GIS vendors treat the coordinate shifts incorrectly. The National Geodetic Survey provides software (LEFTI and NADCON) at a nominal charge to compute datum shifts. Boundary coordinates on older paper copies of soil maps should be converted to the preferred datum (probablyWGS84) before they are digitized.GPS receivers can usually report position information inmore than one format. The most common format is lat/lon (latitude and longitude). Lat/lon coordinates are recorded in angular units of degrees, minutes and seconds. One second of latitude is equal to about 30 meters. GPS receivers may display。

测绘专业英语gps文章翻译

A Unit 15 The Global Positioning SystemPreamble序The Global Positioning System (GPS) is revolutionizing surveying technology. GPS正在革新着测绘技术Like its predecessor, the TRANSIT Doppler system, 像它的前任仪器，中天仪多普勒系统GPS shifts the scene of surveying operations from ground-to-ground measurements to ground-to-sky ,GPS在测量操作上正在改变着从地对地观测到地对空观测的测量环境with obvious implications: visibility of marks is no longer a criterion for their location :operations are possible in nearly all kinds of weather and can be performed during day or night ;and the skills required to utilize the technology are different both in filed operations and data processing.有一些明显的结论标志的可见性不在是定位的一个标准在几乎任何天气、不分昼夜操作都是可以进行的使用这项技术所要求的技能在野外测量和数据处理中都是不同的But GPS is not merely a replacement for TRANSIT .the simultaneous visibility of multiple satellites allows effective cancellation of the major sources of error in satellite observations, with the result that with GPS ,relative positioning accuracies of one part per million ( ppm) or better over distances from one kilometer to thousands of kilometers are possible .This means that GPS Can compete with terrestrial techniques over short distances ,and can achieve more accurate results in less time than TRANSIT observations over longer distances.但GPS不只是代替中天仪。

外文翻译---GPS全球卫星定位系统

GPS相关外文翻译

第一篇中英文互译外文原文Recently, according to the requirements of some important GPS research subjects in the fields of Geodesy, Geophysics, Space-Physics and navigation in China, we studied systematically how to correcting the effects of the ionosphere on GPS, with high-precision and accuracy. As the parts of the main contributions, the research projects focus mainly on how to improve GPS surveying by reducing ionospheric delay for dual/single frequency kinematic/static users: high accuracy correction of ionospheric delay for single/dual frequency GPS users on the earth and in space, China WAAS ionospheric modeling and the theory and method of monitoring of ionosphere using GPS.The main contents of this Ph.D paper consist of two parts:Fisrt part---the outline of research background and the systematic introduction and summarization of the previous research results of this work.Second part---the main contribution and research results of this paper are focused on as follows:(1) How to use the measurements of a dual frequency GPS receiver to determine the ionospheric delay correction model for single frequency GPS of a local range;(2) How to separate the instrumental biases with the ionospheric delays in GPS observation;(3) How to establish a large range grid ionosphere model and use the GPS data of Chinese crust movement observation network to investigate the change law of ionospheric TEC of China area;(4) How to improve the effectiveness of correcting ionospheric delays for WAAS’s users under adverse conditions.(5) How to establish the basic theory and the corresponding framework of monitoring the stochastic ionospheric disturbance using GPS(6) How to improve the modelling ability of ionospheric delay according to its diurnal, seasonal, annual variations based on GPS;(7) How to meet the demand of correcting the ionospheric delay of high-precision orbit determination for low-earth satellite using a single frequency GPS receiver1 Extracting (local) ionospheric information from GPS data with high-precisionThe factors are systematically described and analyzed which limit the precision of using GPS data to extract ionospheric delays. The precision of determining ionospheric delay using GPS is improved based on the further research of the related models and methods. The main achievements of this work include the some aspects as follows:(1) Based on a simple model with constant number of parameters, which consists of a set of trigonometric series functions, a generalized ionospheric model is constructed whose parameters can be adjusted. Due to the property of selecting the different parameters according to the change law of ionospheric delay, the new model has better availability in the field of the related theoretic research and engineering application. The experimental results show that the model can indicate the characteristic of ionospheric actions, improves further the modeling ability of local ionosphere and may be used to correct efficiently ionospheric delay of the single frequency GPS uses serviced by DGPS.(2) Different calculating schemes are designed which are used to analyze in detail the characteristics of the effect from instrumental bias (IB) in GPS observations on determining ionospheric delays. IB is different from noise in GPS observations. The experimental results show that the effect of IB is much larger than that of the noise on estimating ionospheic delay, and IB can cause ionospheric delay measurements to include systematic errors of the order of several meters. Therefore, one must significantly take notice of IB and remove its negative effect, and should not casually consider IB as part of noise whenever GPS data are used to fit ionospheric model or to directly calculate ionospheric delay.(3) Stability of IB is studied with a refined method for separating it from ionospheric delay using multi-day GPS phase-smoothed code data. The experimental results showthat, by using averaging of noise with phase-smoothed code observation，the effect of noise on separating IB from ION can be efficiently reduced, and satellite bias plus receiver bias are relatively stable and may be used to predict the IBs of the next session or even that of the next several days.(4) A new algorithm about static real time determination of ionospheric delay is presented on the basis of the predicted values of IB and the technique of real time averaging of noise and weighted-adjustment of dual P-code and carrier phase measurements. The preliminary results show that the new method, which is by post-processing phase-smoothed code data to calculate the IB and then with them to predict and to correct the IB of data needed to remove its effects in real time in the next observation periods, has relatively better accuracy and effectiveness in estimating ionospheric delay. It is very obvious that the scheme can relatively decrease the number of unknown parameters, can efficiently reduce the main negative effect from instrumental bias, and can be easily used to directly and precisely determine ionospheric delay with dual-frequency GPS data. Hence, the method may be considered as an available scheme to determine ionospheric delays for WAAS and many other large range GPS application systems.2 A method of constructing large range (regional and global) high-precision grid ionosph eric model─—the Different Area for Different Stations (DADS) and its application in ChinaBased on the systematic and further research of the principle and methods of establishing grid ionospheric model (GIM), a new method of establishing a GIM ----- Different Areas for Different Stations (DADS) is investigated which is advantageous for considering the local characters of ionosphere, avoiding the effects of the geometrical construction of GPS reference network on estimating the external precision of the GIM, and improving the precision of calculating model parameters. The above results are used to make a preliminary estimation of the latent precision that can be obtained by establishing a large range high precision grid ionospheric model based on the Chinese crust movement observation network, and to investigate the possibility that the GIM provides high-precision ionospheric correction, and toidentify the relevant problems which need to be solved for the planned GPS Wide area Augmentation System (WAAS) of China.3 A method of efficiently correcting ionospheric delays for WAAS’s users under typical adverse conditions ——the Absolute Plus Relative Scheme (APR-I)The commonly used WAAS’s DIDC received by single frequency GPS receivers can usually provide the effective correction of the ionospheric delays for the users under normal conditions and in the fields of calm ionosphere. However, the ionospheric delays cannot be efficiently accounted for during those periods when the WAAS cannot broadcast the DIDC values to users, or when the receivers cannot receive the DIDCs for whatever reason. The ionospheric delay corrections will be less well known in cases when the variations of the ionospheric delays may be very large due to ionospheric disturbances. The above difficulties cannot be avoided to be encountered and must be solved for the WAAS.For this, a new ionospheric delay correction scheme for single frequency GPS data—the APR-I scheme is proposed which can efficiently address the above problems.1) The theoretic basis of constructing the APR-I SchemeThe WAAS can provide high-precision absolute ionospheric delay estimates when it operates properly. Meanwhile, a single frequency GPS receiver serviced by the WAAS can efficiently determine the relative variation of the ionospheric delays between two arbitrary epochs even under adverse conditions if without considering observation noises.2) On the APR-I SchemeBased on a robust recurrence procedure and an efficient combination approach between absolute ionospheric delays and ionospheric relative changes, the APR-I scheme is present which is an new method of correcting ionospheric delay for single frequency GPS user. The formula of estimating the precision of the APR-I scheme is given. An implementation approach of the APR-I scheme is analyzed as well.The experimental results discussed above show that the APR-I scheme not only retains the characteristic of high accuracy of the DIDC from the WAAS under normalionospheric and reception conditions, but also has relatively better correction effectiveness under different abnormal conditions. The implementation of this method need not change the present basic ionospheric delay correction algorithm of the WAAS. In addition, the APR-I method does not impose new demands on receiver hardware, and only requires a few improvements to receiver software. Hence it can be easily used by single frequency GPS users.4 A new theory of monitoring the random signal —Auto-Covariance Estimation of Variable Samples(ACEVS) and its application in using GPS to monitor the random ionosphereA new approach for monitoring ionospheric delays is found and developed, based on the characteristic of time series observation of GPS, an investigation of the statistical properties of the estimated auto-covariance of the random ionospheric delay when changing the number of samples in the time series, the development of the related basic theory and the corresponding framework scheme, and the further research of using GPS and the above research results to study ionosphere.The concrete work is as follows:1) Studied the Auto-Covariance Estimation of Variable Samples (ACEVS)From a general mathematical aspect, the basic model of ACEVS is established. The theoretic and approximate solution formulas for ACEVS are derived based on the improvement of theory of white noise and then a test raw of the state of a random signal is established based on ACEVS;2) Verified and modeled the possibility of using ACEVS to test the change of state of stochastic delaysThe possibility of using ACEVS to monitor ionosphere is verified in terms of theory. Also it is found that the statistical property of ACEVS is sensitive to the change of the random ionospheric delay, on the basis of modeling the characteristics of ACEVS using a dual frequency GPS receiver. The application conditions of using ACEVS to monitor the variation of TEC extracted by GPS data are preliminarily discussed and analyzed as well.3) Established a preliminary framework scheme of using GPS to monitor thedisturbance of random ionospheric delay.According to ACVES and all other results of the above and the characteristic of the time series observations of GPS, a preliminary framework scheme for monitoring the disturbance of random ionospheric delay using GPS is established. Although this method is proposed for real time monitoring, it can be easily applied to post-processing of GPS data. The framework scheme based on ACVES can be used to design many practical schemes for monitoring ionosphere variation using a (static or kinematic) dual frequency GPS receiver.5 A new method of modelling ionospheric delay using GPS data ——Ionospheric Eclipse Factor Method (IEFM)The Ionospheric Eclipse Factor (IEF) and its influence factor (IFF) of Ionospheric Pierce Point (IPP) is present and a simple method of calculating the IEF is also given. By combining the IEF and IFF with the local time t of IPP, a new method of modelling ionospheric delay using GPS data —Ionospheric Eclipse Factor Method (IEFM) is developed. The IEF and its IFF can efficiently combine the different ionospheric models for different seasons according to the diurnal, seasonal and annual variations of ionosphere. The preliminary experimental results show that the correction accuracy of the ionospheric delay modeled by IEFM is very close to that of using the ionosphere- free observation to correct directly the ionospheric delay, that is, the precision of using IEFM to model ionospheric delay for single GPS users seems to has a breakthrough improvement and be similar to that of using the corresponding dual frequency GPS data to correct directly the ionospheric delays. The IEFM also suits to model the ionospheric delays for a kinematic based–single GPS receiver embeded in low-earth satellite with high rapid due to its good ability in distinguishing the daytime and nighttime of the earth ionosphere for an IPP.6 A new strategy of correcting ionospheric delay for high-precision orbit determination for low-earth satellite using a single frequency GPS receiver ---the APR-II scheme, i.e., Space-based APR schemeAnalyzed the shortcomings of using the previous methods to divide with high accuracy the earth ionosphere into different layers. Used GPS data to model globalionospheric TEC. Established a high precision grid ionospheric model. Discussed the possibility of finding out some local areas whose ionospheric construction and action have relatively better obvious law with respect to the other areas on a global scale. Designed a scheme for combining GPS-grounded data with GPS-spaced data to divide efficiently the ionosphere into some layers. Given the corresponding formula of estimating the precision of the scheme. The preliminary precision estimation and the experimental results show the possibility and property of the above idea of dividing ionosphere into different layers according to application requirement and its implementation scheme. Based on the above research, the APR-II scheme is presented which is a new and combined method of correcting the ionospheric delays of high-precision orbit determination for low-earth satellite using a single frequency GPS receiver. The preliminary experimental results based on two different sets of GPS-grounded data show that the APR-II scheme can provide the effective ionospheric delay correction for high-precision orbit determination for low-earth satellite.中文翻译根据当前大地测量、地球物理、空间物理和导航等领域的科学研究和工程应用中的若干重要GPS科研项目的需要，近年来，我们系统研究了电离层延迟的高精度模拟和改正方法。

毕业论文英文翻译GPS实时监测【范本模板】

GPS Real-Time Supervisory System and Application in the Construction of FaceRockfill DamHUANG Sheng xiang LIU Jingnan ZENG Huai＇enABSTRACTAccording to the quality control needs of filling construction of the face rockfill dam, by means o f the global satellite positioning technology ，the wireless data communication technology, the computer technology and the data processing and analysis technology, and integrating with the roller compaction machine，the GPS real-time supervisory system is developed in this paper。

It can be used to real—timely supervise the construction quality of the roller compaction for filling engineering.The composition and applied characteristics of GPS system，and the key technique problem and solution of the design are discussed。

The height accuracy of GPS system is analyzed and the preliminary application is introduced.KEY WORDS ：GPS; filling construction; quality control; integrated system；face rockfill dam IntroductionAt present , in the quality management of filling construction of the face rockfill dam，the quality control method of “dual controls”is mainly adopted, of which one is manually controling the parameters of roller compaction including thickness and roughness of filling layer and rolled times and rolled speed o f compaction machines,the other is inspecting the test hole sampling manually in the area. The method play a positive role in promoting domestic development of concrete faced rockfill dam。

GPS跟踪系统外文翻译文献

GPS跟踪系统外文翻译文献(文档含中英文对照即英文原文和中文翻译)Sensing Human Activity:GPS Tracking感应人类活动:GPS跟踪Stefan van der Spek1,*,Jeroen van Schaick1,Peter de Bois1,2and Remco de Haan1Abstract:The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools,but also as instruments used to capture travelled routes:as sensors that measure activity on a city scale or the regional scale.TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres,Norwich,Rouen and Koblenz,and in another experiment for collecting activity data of13families in Almere(The Netherlands)for one week.The question posed in this paper is:what is the value of GPS as‘sens or technology’measuring activities of people?The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings addingnew layers of knowledge to urban studies,but the use of GPS-technology and deploymentof GPS-devices still offers significant challenges for future research.摘要：增强GPS技术支持使用GPS设备不仅作为导航和定位工具,但也为仪器用来捕捉旅行路线:作为传感器,测量活动在一个城市或区域范围内规模。

全球卫星导航系统作文英文

全球卫星导航系统作文英文英文：Global satellite navigation systems, such as GPS (Global Positioning System) and GLONASS (Global Navigation Satellite System), have revolutionized the way we navigate and locate ourselves on the Earth. These systems use a network of satellites to provide precise location and time information to users anywhere on the planet. As a frequent traveler and outdoor enthusiast, I have personally experienced the convenience and reliability of these global satellite navigation systems.For example, during a recent hiking trip in a remote mountainous area, I heavily relied on my GPS device to navigate through the rugged terrain and reach mydestination safely. The GPS provided me with accurate real-time positioning and helped me stay on track even when the trail was not well-marked. Without the assistance of the satellite navigation system, I could have easily gottenlost and faced potential danger in the wilderness.Furthermore, I often use GPS in my daily life for driving directions. Whether I am exploring a new city or simply commuting to work, the GPS navigation feature in my car or smartphone has become an indispensable tool for me. It not only helps me avoid getting lost, but also provides real-time traffic updates and alternate routes to save time and reduce stress during my travels.In addition to personal use, global satellite navigation systems have also had a significant impact on various industries, including aviation, maritime, and agriculture. Pilots rely on GPS for precise navigation and landing, while maritime vessels use it for safe andefficient navigation at sea. Farmers use satellite-guided tractors and equipment to optimize crop planting and harvesting, leading to increased productivity and reduced environmental impact.中文：全球卫星导航系统，如GPS（全球定位系统）和GLONASS（全球导航卫星系统），已经彻底改变了我们在地球上导航和定位的方式。

全球定位系统的介绍外文翻译

毕业设计（论文）外文参考资料及译文译文题目：Introduction to the Global Positioning System全球定位系统的介绍学生姓名：学号：专业：集成电路设计与集成系统所在学院：电子工程学院指导教师：职称：201x年 xx月xx日Introduction to the Global Positioning System---------From “Corvallis Microtechnology, Inc.1996”Chapter One: What is GPS?The Global Positioning System (GPS) is a location system based on a constellation of about 24 satellites orbiting the earth at altitudes of approximately 11,000 miles. GPS was developed by the United States Department of Defense (DOD), for its tremendous application as a military locating utility. The DOD's investment in GPS is immense. Billions and billions of dollars have been invested in creating this technology for military uses. However, over the past several years, GPS has proven to be a useful tool in non-military mapping applications as well.GPS satellites are orbited high enough to avoid the problems associated with land based systems, yet can provide accurate positioning 24 hours a day, anywhere in the world. Uncorrected positions determined from GPS satellite signals produce accuracies in the range of 50 to 100 meters. When using a technique called differential correction, users can get positions accurate to within 5 meters or less.Today, many industries are leveraging off the DOD's massive undertaking. As GPS units are becoming smaller and less expensive, there are an expanding number of applications for GPS. In transportation applications, GPS assists pilots and drivers in pinpointing their locations and avoiding collisions. Farmers can use GPS to guide equipment and control accurate distribution of fertilizers and other chemicals. Also，GPS is used for providing accurate locations and as a navigation tool for hikers, hunters and boaters.Many would argue that GPS has found its greatest utility in the field of Geographic Information Systems (GIS). With some consideration for error, GPS can provide any point on earth with a unique address (its precise location). A GIS is basically a descriptive database of the earth (or a specific part of the earth). GPS tells you that you are at point X,Y,Z while GIS tells you that X,Y,Z is an oak tree, or a spot in astream with a pH level of 5.4. GPS tells us the "where". GIS tells us the "what". GPS/GIS is reshaping the way we locate, organize, analyze and map our resources.Chapter Two: Trilateration - How GPS Determines a LocationIn a nutshell, GPS is based on satellite ranging - calculating the distances between the receiver and the position of 3 or more satellites (4 or more if elevation is desired) and then applying some good old mathematics. Assuming the positions of the satellites are known, the location of the receiver can be calculated by determining the distance from each of the satellites to the receiver. GPS takes these 3 or more known references and measured distances and "triangulates" an additional position.As an example, assume that I have asked you to find me at a stationary position based upon a few clues which I am willing to give you. First, I tell you that I am exactly 10 miles away from your house. You would know I am somewhere on the perimeter of a sphere that has an origin as your house and a radius of 10 miles. With this information alone, you would have a difficult time to find me since there are an infinite number of locations on the perimeter of that sphere.Second, I tell you that I am also exactly 12 miles away from the ABC Grocery Store. Now you can define a second sphere with its origin at the store and a radius of 12 miles. You know that I am located somewhere in the space where the perimeters of these two spheres intersect - but there are still many possibilities to define my location.Adding additional spheres will further reduce the number of possible locations. In fact, a third origin and distance (I tell you am 8 miles away from the City Clock) narrows my position down to just 2 points. By adding one more sphere, you can pinpoint my exact location. Actually, the 4th sphere may not be necessary. One of the possibilities may not make sense, and therefore can be eliminated.For example, if you know I am above sea level, you can reject a point that has negative elevation. Mathematics and computers allow us to determine the correct point with only 3 satellites.Based on this example, you can see that you need to know the following information in order to compute your position:A) What is the precise location of three or more known points (GPS satellites)?B) What is the distance between the known points and the position of the GPS receiver?Chapter Three: How the Current Locations of GPS Satellites are Determined GPS satellites are orbiting the Earth at an altitude of 11,000 miles. The DOD can predict the paths of the satellites vs. time with great accuracy. Furthermore, the satellites can be periodically adjusted by huge land-based radar systems. Therefore, the orbits, and thus the locations of the satellites, are known in advance. Today's GPS receivers store this orbit information for all of the GPS satellites in what is known as an almanac. Think of the almanac as a "bus schedule" advising you of where each satellite will be at a particular time. Each GPS satellite continually broadcasts the almanac. Your GPS receiver will automatically collect this information and store it for future reference.The Department of Defense constantly monitors the orbit of the satellites looking for deviations from predicted values. Any deviations (caused by natural atmospheric phenomenon such as gravity), are known as ephemeris errors. When ephemeris errors are determined to exist for a satellite, the errors are sent back up to that satellite, which in turn broadcasts the errors as part of the standard message, supplying this information to the GPS receivers.By using the information from the almanac in conjuction with the ephemeris error data, the position of a GPS satellite can be very precisely determined for a given time.Chapter Four: Computing the Distance Between Your Position and the GPSSatellitesGPS determines distance between a GPS satellite and a GPS receiver by measuring the amount of time it takes a radio signal (the GPS signal) to travel from the satellite to the receiver. Radio waves travel at the speed of light, which is about 186,000 miles per second. So, if the amount of time it takes for the signal to travel from the satellite to the receiver is known, the distance from the satellite to the receiver (distance = speed x time) can be determined. If the exact time when the signal was transmitted and the exact time when it was received are known, the signal's travel time can be determined.In order to do this, the satellites and the receivers use very accurate clocks which are synchronized so that they generate the same code at exactly the same time. The code received from the satellite can be compared with the code generated by the receiver. By comparing the codes, the time difference between when the satellite generated the code and when the receiver generated the code can be determined. This interval is the travel time of the code. Multiplying this travel time, in seconds, by 186,000 miles per second gives the distance from the receiver position to the satellite in miles.Chapter Five: Four (4) Satellites to give a 3D positionIn the previous example, you saw that it took only 3 measurements to "triangulate" a 3D position. However, GPS needs a 4th satellite to provide a 3D position. Why?? Three measurements can be used to locate a point, assuming the GPS receiver and satellite clocks are precisely and continually synchronized, thereby allowing the distance calculations to be accurately determined. Unfortunately, it is impossible to synchronize these two clocks, since the clocks in GPS receivers are not as accurate as the very precise and expensive atomic clocks in the satellites. The GPS signals travel from the satellite to the receiver very fast, so if the two clocks are off by only a small fraction, the determined position data may be considerably distorted.The atomic clocks aboard the satellites maintain their time to a very high degree ofaccuracy. However, there will always be a slight variation in clock rates from satellite to satellite. Close monitoring of the clock of each satellite from the ground permits the control station to insert a message in the signal of each satellite which precisely describes the drift rate of that satellite's clock. The insertion of the drift rate effectively synchronizes all of the GPS satellite clocks.The same procedure cannot be applied to the clock in a GPS receiver. Therefore, a fourth variable (in addition to x, y and z), time, must be determined in order to calculate a precise location. Mathematically, to solve for four unknowns (x,y,z, and t), there must be four equations. In determining GPS positions, the four equations are represented by signals from four different satellites.Chapter Six: The GPS Error BudgetThe GPS system has been designed to be as nearly accurate as possible. However, there are still errors. Added together, these errors can cause a deviation of +/- 50 -100 meters from the actual GPS receiver position. There are several sources for these errors, the most significant of which are discussed below:Atmospheric ConditionsThe ionosphere and troposphere both refract the GPS signals. This causes the speed of the GPS signal in the ionosphere and troposphere to be different from the speed of the GPS signal in space. Therefore, the distance calculated from "Signal Speed x Time" will be different for the portion of the GPS signal path that passes through the ionosphere and troposphere and for the portion that passes through space.As mentioned earlier, GPS signals contain information about ephemeris (orbital position) errors, and about the rate of clock drift for the broadcasting satellite. The data concerning ephemeris errors may not exactly model the true satellite motion or the exact rate of clock drift. Distortion of the signal by measurement noise can further increase positional error. The disparity in ephemeris data can introduce 1-5 meters ofpositional error, clock drift disparity can introduce 0-1.5 meters of positional error and measurement noise can introduce 0-10 meters of positional error.Ephemeris errors should not be confused with Selective Availability (SA), which is the intentional alteration of the time and ephemeris signal by the Department of Defense.A GPS signal bouncing off a reflective surface prior to reaching the GPS receiver antenna is referred to as multipath. Because it is difficult to completely correct multipath error, even in high precision GPS units, multipath error is a serious concern to the GPS user.Chapter Seven: Measuring GPS AccuracyAs discussed above, there are several external sources which introduce errors into a GPS position. While the errors discussed above always affect accuracy, another major factor in determining positional accuracy is the alignment, or geometry, of the group of satellites (constellation) from which signals are being received. The geometry of the constellation is evaluated for several factors, all of which fall into the category of Dilution Of Precision, or DOP.DOP is an indicator of the quality of the geometry of the satellite constellation. Your computed position can vary depending on which satellites you use for the measurement. Different satellite geometries can magnify or lessen the errors in the error budget described above. A greater angle between the satellites lowers the DOP, and provides a better measurement. A higher DOP indicates poor satellite geometry, and an inferior measurement configuration.Some GPS receivers can analyze the positions of the satellites available, based upon the almanac, and choose those satellites with the best geometry in order to make the DOP as low as possible. Another important GPS receiver feature is to be able to ignore or eliminate GPS readings with DOP values that exceed user-defined limits. Other GPS receivers may have the ability to use all of the satellites in view, thus minimizing the DOP as much as possible.全球定位系统的介绍----摘自Corvallis Microtechnology公司，1996第一章：什么是GPS？全球定位系统（ＧＰＳ）是一种基于２４颗高度大约１１０００英里的地球轨道卫星的定位系统。

GPS硬件系统英文文献

Summarizing The Global Positioning SystemAbstract:Global Positioning System is based on the background of the United States Department of Defense.It is designed,invested,developed,and operated by the United States Department of Defense ,GPS is a satellite-based positioning and time transfering GPS positioning function has a wide range of applications in the modern measurement and a more modern building.GPS-RTK technology is also widely used in modernization building, and now GPS has also been shown to be an important civilian communities of interest, and increasingly wide range of applicated.Keyword:GPS,Locating，RTK，Lay out，SurveyThe GPS receiver may receive and use in the time service accurately to the nanosecond level time information; will use in to forecast the future for several months the satellite to locate the summary position forecast star experience; Uses in calculates when the localization to need the satelli te coordinates the broadcast star experience, the precision is (each satellite is different several meter to several dozens meters~changes as necessary); As well as GPS system information, like satellite condition and so on.The GPS receiver may obtain the satellite sign to the code to the receiver distance, because includes the receiver satellite clock the error and the atmosphere propagated error, therefore is called the false distance. The false distance obtains which to the OA code is called the UA code false distance, the precision approximately is about 20 meters, obtains the false distance to P yard to be called P yard false distance, the precision approximately is about 2 meters.The GPS receiver to the satellite signal which receives, carries on the decoding or uses other technologies, will modulate after the carrier the information removes, will be allowed to restore the carrier. Strict says, the carrier phase should be called the carrier beat frequency phase, it is receives produces the Doppler shift influence satellite signal carrier phase and receiver this machine vibration difference of the signal phase. Generally experience Yuan time which determined in the receiver clock surveyed, maintains to the satellite signal track under, may record the phase change value, but starts time the observation receiver and the satellite oscillator phase change value is does not know, namely misty degree of whole week, only can calculate in the data processing as the parameter solution. Phase observation value precision high to millimeter, but the premise is solves misty degree of whole week, therefore only has when therelative localization, and has a section continuously observes the value can use the phase observation value, but must achieve meters down to themillimeter level also only to be able to use the phase observation value.When localization observation, if the receiver is opposite to the earths surface movement, then is called the dynamic localization, like uses in summary navigation localization the and so on Chef Chuan precision is 30-100 meter false distance simple point localization, either uses in the city vehicles navigation localization rice level precision false distance difference localization(RTK), the real-time difference localization needs the data chain real-time transmits two or many stations observation data calculates together.When localization observation, if the receiver is opposite to the earths surface static, then is called the static localization, when carries on controls the net observes, generally selects this method by several receivers also to observe, it can maximum limit display GPS the pointing accuracy,special-purpose Yu Zheizhong the goal receiver is called the earth receiver,is in the receiver a performance best kind. At present, GPS already could achieve the earths crust performance observation the precision request, IGS year to year the measuring platform already can constitute millimeter level the global coordinates frame.全球定位系统概述摘要：全球定位系统是以美国国防为背景，由美国国防部设计、投资、开发、和运行的。

关于gps的英语作文

关于gps的英语作文GPS, short for Global Positioning System, has become an integral part of our daily lives. It is a satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth. GPS has transformed the way we travel, navigate, and communicate with one another.GPS，即全球定位系统，已成为我们日常生活中不可或缺的一部分。

它是一个卫星导航系统，在任何天气条件下，在地球上或附近的任何地方提供位置和时间信息。

GPS已经改变了我们的旅行方式、导航方式以及人与人之间的沟通方式。

One of the most significant impacts of GPS is on the transportation industry. GPS technology has revolutionized the way we navigate our cars, buses, trains, and airplanes. With GPS devices, drivers can easily find their routes, avoid traffic congestion, and reach their destinations in a more efficient manner. This has not only improved the overall transportation experience for individuals but also enhanced the efficiency and safety of transportation systems.GPS对交通运输行业的影响最为显著。

全球定位系统英文作文

全球定位系统英文作文英文：Global Positioning System (GPS) is a satellite-based navigation system that provides location and time information in all weather conditions and anywhere on or near the Earth. It was developed by the United States Department of Defense and became fully operational in 1995.GPS works by using a network of 24 satellites in orbit around the Earth. These satellites transmit signals that are picked up by GPS receivers on the ground. By measuring the time it takes for the signal to travel from thesatellite to the receiver, the GPS receiver can calculate its distance from the satellite. By receiving signals from multiple satellites, the GPS receiver can determine its precise location.GPS has revolutionized navigation and has become an essential tool for a wide range of applications, includingaviation, maritime navigation, surveying, and outdoor recreation. It has also become an integral part of modern transportation systems, such as cars and trucks, and is used for tracking and monitoring vehicles.One of the most common uses of GPS is in personal navigation devices, such as smartphones and GPS watches. These devices use GPS to provide turn-by-turn directions and real-time traffic updates, making it easier for people to navigate unfamiliar areas. GPS has also made it easier for people to track their fitness activities, such as running and cycling, by providing accurate distance and speed measurements.In addition to its practical applications, GPS has also had a significant impact on society and culture. It has changed the way we think about and experience space and time, and has enabled new forms of communication and social interaction. For example, GPS-enabled social media apps allow people to share their location and connect with others in real-time.Overall, GPS has become an indispensable tool in our daily lives, and its impact will continue to be felt in the years to come.中文：全球定位系统（GPS）是一种基于卫星的导航系统，可以在任何天气条件下和地球上或附近的任何地方提供位置和时间信息。

GPS全球定位系统中英文资料对照外文翻译

(文档含英文原文和中文翻译) 中英文资料对照外文翻译Summarizing The Global Positioning System Abstract:Global Positioning System is based on the background of the United StatesDepartment of Defense.It is designed,invested,developed,and operated by the United States Department of Defense ,GPS is a satellite-based positioning and time transfering GPS positioning function has a wide range of applications in the modern measurement and a more modern building.GPS-RTK technology is also widely used in modernization building, and now GPS has also been shown to be an important civilian communities of interest, and increasingly wide range of applicated.Keyword:GPS,Locating，RTK，Lay out，Survey1.BackgroundThe 50s, the former U.S.S.R has not launched humanities first artificial earthsatellite, the American scientists in along its track research in, had discovered theDoppler shift phenomenon, and has facilitated Doppler satellite navigation posi- tioningsystem completing using this principle, has obtained the enormous success in themilitary and the civi aspect, was in a navigation localization history leap, our countryonce has also introduced many Doppler receiver, applied to the island associationmeasured, the Earth explored and so on the applied to the island association measured,the Earth explored and so on the domain. But because Doppler satellite orbit highly low,signal-carrier frequency low, the track precision enhances with difficulty, causes thepointing accuracy lowly, satisfies the geodetic survey or the project survey request, ismore impossible to use in the astronomy Earth dynamics research. In order to enhancethe satellite positioning the precision,US started from 1973 to prepare for constructionglobal positioning system GPS (Global Positioning System).After has entered the planproof, the system test stage,started in 1989 to launch the official work satellite,andcompletely completed in 1994, investment use. The GPS system spaceartially iscomposed by twenty one satellites, evenly distributes in six orbit, the ground level is20,000 Kilometers, the inclination of orbit is 55, the flat heart rate approximately is 0,the week contract is 12 hours, the satellite to the earth launching two wave bandsintelligence signals,the intelligence signal frequency respectively is 1575.442 megacycles per second (the L2 wave band), on the satellite has installed the precision veryhigh atomic clock, guarantees the frequency the stability, modulates in the carrier has the expression satellite position the broadcast star experience, use in the range finder C/A code and P yard, as well ad other system information, can in the global scope, to willfully multi-user provide the high accuracy, all-weather, is continual, real-time three dimensional measures fast, the three dimensional localization and the time service.The GPS system control section by is located in the American foundations of the states 5 monitoring stations to be composed, these stand did not ask breaks Carries on the observation to GPS satellite, and will calculate and the forecast information by the infusion stands renews to the satellite information.The GPS system user is extremely covert, it is one kind of one-way system,the user only receives but does not need the transmitting message, and therefore user' s quantity also is not limited. Although GPS is the unification starts is, but very quantity also is not limited. Although GPS recei ver and processing software emerge in abundance. At present the receiver which appears in the Chinese market mainly has ROGUE,ASHTECH, TRIMBLE, LEICA, SOKKIA, TOPCON and so on.. Can carry on the observation to two frequencies the receiver to be called the double frequency receiver, only can carryon the observation to a frequency the receiver to become the inference. Says regarding the mapping user, GPS has caused the revolutionary change in the mapping domain, at present, in the scope several thousand kilometers controls network, in the precision from hundred to the millimeter level localization, generally all GPS took the first choice method, is day by day mature along wi th the RTK technology, GPS started to decimeter and even a centimeter level layout, domain seepage and so on high accuracy dynamic localization.The international GPS geodetic survey served IGS with Earth dynamics from 1992, has established many data storage and the processing center in the whole world, year to year observed a station with hundred, our country has also set up Shanghai Y u Shan, Wuhan, Xian, Taiwan and so on many year to year measuring platforms station, these stations observation data passed on every day through the internet net to US' S data storage center, IGS also nearly real-time synthesizes various data processing center the result, and the participant international earth rotation served the IERS global coordinates reference system maintenance and the earth rotation parameter issue. The user also mayfree on-line obtain product and so on observation data and precise star experience from internet.The GPS system real-time navigation pointing is very high,US hasimplemented the so-called SA policy in 1992, namely reduces the broadcaststar to undergo the star posi tion precision, reduces the star clock to change thepositive number the precision, adds on the high frequency vibration to thesatellite datum frequency (to cause false distance measuring accuracy to reducewith phase ), latter has implemented the A-S policy, soon P yard change is Y yardnamely further limi ts to the precise false distance survey, but American military and special permission user not these polices influences, but US in order to obtain the bigger commercial interest, these policy ends are cancelled.2.GPS localization principalThe GPS receiver may receive and use in the time service accurately to the nanosecond level time information; will use in to forecast the future for several months the satellite to locate the summary position forecast star experience; Uses in calculates when the localization to need the satelli te coordinates the broadcast star experience, the precision is (each satellite is different several meter to several dozens meters~changes as necessary); As well as GPS system information, like satellite condition and so on.The GPS receiver may obtain the satellite sign to the code to the receiver distance, because includes the receiver satellite clock the error and the atmosphere propagated error, therefore is called the false distance. The false distance obtains which to the OA code is called the UA code false distance, the precision approximately is about 20 meters, obtains the false distance to P yard to be called P yard false distance, the precision approximately is about 2 meters.The GPS receiver to the satellite signal which receives, carries on the decoding or uses other technologies, will modulate after the carrier the information removes, will be allowed to restore the carrier. Strict says, the carrier phase should be called the carrier beat frequency phase, it is receives produces the Doppler shift influence satellite signal carrier phase and receiver this machine vibration difference of the signal phase. Generally experience Yuan time which determined in the receiver clock surveyed, maintains to the satellite signal track under, may record the phase change value, butstarts time the observation receiver and the satellite oscillator phase change value is does not know, namely misty degree of whole week, only can calculate in the data processing as the parameter solution. Phase observation value precision high to millimeter, but the premise is solves misty degree of whole week, therefore only has when the relative localization, and has a section continuously observes the value can use the phase observation value, but must achieve meters down to themillimeter level also only to be able to use the phase observation value.According to the locate mode, the GPS localization divides into the simple point localization and the relative localization (difference localization). The simple point localization is according to a receiver observation data determined the receiver position the way, it only can use the false distance view survey, may use in Chef Chuan and so on the summary navigation localization. The relative localization (difference localization) is according to two above receivers observation data determined between the observation point the relative position method, it already may use the false distance view survey also to be possible to use the phase view survey, the geodetic surveyor the project survey should use the phase observation value to carryon the relative localization. Has contained the satellite and receiver ZhongChai, the atmospheric dissemination in the GPS view survey retards, error and so on multipart effect, when localization error the influence, when carries on the relative localization the majority of public errors are counterbalanced or weaken, therefore the pointing accuracy greatly will enhance, the double frequency receiver will be allowed to act according to two frequencies in the view survey counterbalance atmosphere the ionosphere-path error main part, will request high in the precision, between the receiver the distance wi11 be farther when (atmosphere will have obvious difference), will be supposed to select the double frequency receiver.When localization observation, if the receiver is opposite to the earths surface movement, then is called the dynamic localization, like uses in summary navigation localization the and so on Chef Chuan precision is 30-100 meter false distance simple point localization, either uses in the city vehicles navigation localization rice level precision false distance difference localization(RTK), the real-time difference localization needs the data chain real-time transmits two or many stations observationdata calculates together.When localization observation, if the receiver is opposite to the earths surface static, then is called the static localization, when carries on controls the net observes, generally selects this method by several receivers also to observe, it can maximum limit display GPS the pointing accuracy,special-purpose Yu Zheizhong the goal receiver is called the earth receiver,is in the receiver a performance best kind. At present, GPS already could achieve the earths crust performance observation the precision request, IGS year to year the measuring platform already can constitute millimeter level the global coordinates frame.3.RTK technologiesThe conventional GPS measuring technique, like the static state, the fast static state , the dynamic survey all~eed afterwards to carryon the solution to calculate can obtain a centimeter level the precision, but RTK is can real-time obtain the centimeter level pointing accuracy in the open country the measuring technique, it has used the carrier phase dynamic real-time difference (Real-timekinematics) the method, is the GPS application significant milestone, its appearance for the project layout, the terrain mapping, each kind of control survey has brought the new dawn, enormously enhanced the field operation work efficiency.The high accuracy GPS survey must use the carrier phase observation value,the RTK localization technology, it can real-time provide in assigns in the coordinate system the three dimensional localization result, and achieves the centimeter level precision. Under the RTK work pattern, the datum stands through the data chain transmi ts together its observation value and the survey station coordinates information for the mobile station. Mobile stands not only receives the data through the data link which stands from the datum, but also must gather the GPS observation data, and composes the difference observation value in the system to carryon the real-time processing, simultaneously produces the centimeter level localization result, a lasted. The mobile station may be at the static condition, also may be at the state of motion; May first carryon the initialization after the fixed point to enter the dynamic work again, also may under the dynamic condition directly opening machine,and completes theweek fuzziness search solution under the dynamic environment. After end knows the number solution to be fixed, then carries on each calendar Yuan real-time processing, so long as can maintain four above satellites phases observation value the track and the essential geometric figure ,then the mobile station may produce the centimeter level localization result as necessary.The RTK technology key lies in the data processing technology and the data transmission technology, when the RTK localization requests the datum station receiver real-time the observation data (false distance observation value, phase observation value) and the know data transmission for the mobile station receive, the data quantity quite big, generally all requests 9,600 bauds rate, this in on radio is not difficult to realize.4.The application of RTK(1)Each kind of control surveyThe traditional geodetic survey, the project control survey uses the triangular net, the line-network method executes measured, not only requires a lot of work time-consuming, request Indivisibility, moreover the precision distribution non-uniformity, also at the field operation did not know how the precision, does use conventional the GPS static state survey, the fast static state, the false dynamic method, survey in the process at field operation not to be able real-time to know the pointing accuracy, after if surveys completes, after returns to house processing to discover the precision does no t gather the request, but also must return measured, but uses RTK to carryon the control survey, can real-time know the pointing accuracy, if the fruits and cakes position precision request has satisfied, the user was allowed to stop observing, how moreover knew the observation quality, This may greatly enhance the work efficiency. If uses in the road control survey RTK,electronic circuit control survey, the hydraulic engineering control survey, the geodetic survey, then not only may greatly reducethe manpower intensi ty, the economical expense, moreover greatly enhances the working efficiency,measured a control point may complete in several minutes even several seconds.(2)Terrain mappingIn the past measured when topographic diagram generally first must in measure area establishment chart root control point, then on chart root control point top carriage entire station meter or altazimuth coordination small flat panel mapping, now develops the field operation with the entire station meter and the electronic hand coordination thing code, uses big scale mapping software to carryon the mapping, even develops recent field operation electron dull mapping and so on, all requests in the survey station to measure all around terrain landform and so on department point, these points all wi th survey station indivisibility, moreover generally requests at least 2-3 person to operate, needs when puts together the chart once the precision not to gather the request also to obtain the field operation to return measured,when now uses RTK, only needs a person to carry the instrument in on the terrain landform department point dull 12 second kinds which must measure, and simultaneously inputs the characteristic code, through hand book may real-time know the position precision, after measured a region returns to in the room, may output the topographic diagram by the specialized software connection which requests, like this uses RTK only to need a person to operate,does not request a between indi visibi Ii ty, greatly enhanced the working efficiency, uses the RTK coordination electron hand book to be allowed to survey each kind of topographic diagram, I ike the ordinary mapping, the track，line strip the shape topographic diagram surveying, road pipeline topographic diagram surveying, coordinates the depth-finding device to be allowed to use in to measure the reservoir topographic diagram, Navigation sea mapping and so on.(3)LayoutLayout surveys an application branch, it request through the certain method to use the certain instrument the spot position which artificial designs in really for to demarcate, in the past used the convention layout the method very many, like the altazimuth junction met layout, when the ent ire 50 station meter and so on, generally layout a design position, often needed the back and forth bile target, moreover took 2-3 person to operate, simultaneously also requested the indivisibility situation in the process to be good, in the production application the efficiency was not very high, sometimes layout encountered the difficult situation to be able to draw support fromYu Hindu the methodto layout. Sometimes, if uses the RTK technology layout, only must the spot position coordinates which designs input to the electron hand, is carrying the GPS receiver, it can remind you to walk to want to layout a position, both rapid and convenient, because GPS is comes directly through the coordinates layout,the precision is very high, thus can greatly enhance efficiency, also only needs a person to operate.5. The application of GPSGPS offers for military and makes a reservation and sets up accurately at first, it is still controlled by the American military so far. Military GPS products is it confirm and follow in field advancing soldering and coordinating of equipment in to used for mainly, the gunship for the sea navigates, offers the position and navigation information for military aircraft.(1) The GPS system use is extensivelyAt present, application, GPS of system very extensive already, we can use GPS signal can carryon sea, empty and navigation of land, the guidance of the guided missile, earth measurement and accurate localization of project measurement., transmission of time and measurement of the speed,etc.For survey and draw field,GPS satellite fix technology is it set up nationwide earth measurement of high accuracy control network to use for already, determine global dynamic parameter of earth;Used for setting up land marine earth measurement datum, unite and examines and surveys and draws in the ocean the high-accuracy island land;Used for moni toring plate motion state of the earth and the earths crust deformation;Used in project measure,is it set up city and project control main means of network to become For determine Aero-Space photograph camera position in the twinkling of an eye, realize for a small amount of ground control or there is no aerial survey controlled in region to become and pursue fast, technical revolution causing the geographical information system,global environmental remote to follow their monitor.A lot of commerce and government organs use GPS equipment to follow their vehicle position;This generally needs to draw support fromwireless communication technology.Some GPS receiver integrated radio, radio telephone move data terminal is it meets need, motorcade of management to come.(2) Appearance of the resource environment of pluralistic spaceAt present, GPS, GLONASS, INMARSAT waits for the system to all possess and navigate to orient the function, formed the pluralistic room resource environment. This pluralistic space environment ,has impelled and fumed a piece of common tactics internationally and folly, namely on one hand fully utilize the existing system, on the other hand prepare to establish folk GNSS system actively ,by the tome around the2010,GNSS folk system build our purely, the woke world form the tendency that GPS/GLONASS/GNSS stood like the legs of a tripod, could get rid of the reliance on the single system fundamentally, form owning in common, security resource environment which world shares of worlk.World can is it is it use realm at most as single navigation means to navigate satelli te to enter. This international and folk strategy, there id influence and force U.S.A to use the policy to make more omen adjustment to its GPS converselu. Inaword , because of the establishment of the resource environment of pluralistic space ,have created an unprecedented gapped international environment for the development and application of GPS.(3) Develop gaps industryGPS Will form industrialization like the automobile, wireless communication at present in the future, US>A strengthen wide area systematic WAAS (namely wide area is it revise date chain transfer to already, it make geostationary satellite it have C? A yards of function too, form wide area the GPS strengthen system of) plan international standard of developing into of. Some units produce car-mounted GPS system too at present in our country.For GPS industry of developing our country, already China GPS project centrehas been established in Wuhan.全球定位系统概述摘要：全球定位系统是以美国国防为背景，由美国国防部设计、投资、开发、和运行的。

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外文资料及译文1.外文资料全球定位系统第一节The principle of GPS一、GPSGPS(Navigation Satellite Timing and Ranging /Global Position System )，GPS clock and distance navigation system/global positioning systems, referred to as globalpositioning system (GPS), along withthe rapid development of modernscience and technology, and set up anew generation of satellite navigationand positioning system precision.Global positioning system (GPS) is in1973 by U.S. defense forces began toorganize, and common basiccompletion in 1993. This systemconsists of space constellation, groundcontrol and user receiver is composedof three parts.（一）Global positioning system 图1-1 GPS Satellite distribution1.1 Space constellationGPS space by 24 working partconstellation spare satellite and three satellite. Work in 6 orbit satellite distribution within the surface. Each track surface distribution has 3 ~ 4 satellite, satellite orbits earth's equator Angle relative to the average height of 55, orbit for 20200 kilometers. Satellite operating cycle for 11 hours 45 minutes. Therefore, in the same station daily satellite layout is roughly same, just four minutes every day in advance. Each satellite about 5 hours every day in the horizon, located above the horizon of the satellite number with more time and place, at least 4 November, most. This layout can guarantee on earth at any time, any place can also observed above four satellites.Satellite signal transmission and reception and the influence, so the GPS is a global, all-weather real-time navigation and positioning for system. After the completion of the global positioning system, its work in the space distribution of satellite 1-1 as shown. GPS satellite zips are installed on the light, microprocessors, message signal emission equipment, storage, and provide power supply by solar cells have little fuel, satellite is used to regulate the satellite orbit and posture, and in the monitor of instruction, start spare satellite.1.2 The ground monitoring systemGPS ground monitoring system in the world by five sites. One master station, 3 injection station. Five monitor are equipped with automatic acquisition, data center, double-frequency GPS receiver, precision clock, environmental data sensors and computing devices, and to master station provides all kinds of observation data. Master station (in Colorado) for system management and data processing center, its main content is the use of this site and other monitor the observation data of the satellite's star calendar calculation and satellite clock and atmospheric delay correction parameter, provide global positioning system, and the time base station, these parameters to adjust sidetracked into orbit, the satellite to enable spare satellite instead of failure satellite, etc. Injection station master station will be calculated and satellite star calendar, clock, satellite navigation message and other control commands into corresponding satellite etc, and storage system into the correctness of monitoring information. Besides, the master station, GPS ground monitoring system, various unattended highly automated and standardized work.1.3 User equipment partsUser equipment including GPS receiver host, antenna, power and data processing software component. The host for the microcomputer, quartz oscillators core, and the corresponding input and output interface, and equipment. In the special software under control, the host for homework, satellite data acquisition, processing and storage of the equipment, the system state inspection, alarm and maintenance, the receiving system of automatic management. Antenna, often used for collecting all from each azimuth, arbitrary nonnegative Angle of satellite signal. Due to the satellite antenna pedestal weak signal in a pre-amplifier, amplification, reoccupy coaxial cable input host. Power supply for host and aerial part, can use through rectifier voltage, the mains, also can use the accumulator.（二）Global positioning system (GPS) signalsGPS satellite launch a coherent wave, the wavelength 1L and frequency respectively 2L ：f MHZ,cm f MHZ,cm L L L L 11221575421912276024====..λλ1L and 2L as a carrier with two modulation signal, a kind of navigation signal, another kind is message signal. Navigation signal S Mb 023.1 is divided again, frequency m A C 293=λ for code rate for the coarse yards (C/A code) and the rate SMb 023.1for the essence, the frequency of m p 3.291=λcode (P). Thick yards (C/A code) repeat each signal encoding, can quickly capture signal, according to the design for rough positioning, Pure code (P) yards signal encoding every seven, and repeat each satellite, structure is very complex, not capture, but can be used for accurate positioning. Message signal while the rate s bit 50to the carrier 1L and 2L modulation in, including satellite, the correct star calendar and satellite working state. Through the message signal receiver can choose the best one group of graphics, positioning signals observation data processing..第二节 GPS Positioning method一、 GPS Positioning method classification（一）、 The static and dynamic positioningBy means of static GPS positioning and can be divided into dynamic positioning.1、Static positioningIf you stay in the surrounding relatively fixed protection can not perceive motion, or movement is so slowly that require months or years, namely that can be reflected in the earth for fixed-point relative coordinates is fixed, the determination method for the coordinates of static positioning is called. In the mathematics model of the static localization, the position is constant. Due to the rapid solutions of GPS "unknown" technology of the cycle time of operation, static already shortened to a few minutes, so, in addition to the original geodetic measurement and monitoring of the force applied, rapid static orientation has been widely applied to the common measurement and engineering measurement.2、 Dynamic positioningCars, ships, aircraft and aircraft in motion, people often need to know their real-time position. In these sports carrier mounted on GPS receiver, real-time GPS signals measured antenna location, called the GPS kinematic positioning. If the only measure the real-time position, the carrier of sports also determine the speed, time and location, etc, thus guidingstatus parameters to reserve the object orientation, called the navigation movement. GPS navigation is virtually dynamic positioning.(二)、Absolute positioning and relative locationAccording to determine the GPS receiver in earth coordinate system in different position, can be divided into a single absolute positioning and the relative positioning, such as machine, 2-1.1、Absolute positioning图2-1 Absolute and relative positioningTo determine the absolute positioning is independent coordinate system in the position of the dot. Because single absolute positioning error by satellite reception when the effect, low precision. Mainly used for low precision dynamic positioning, such as ships, aircraft navigation of mineral resources, geological investigation, Marine fishing and determine the relative position of the initial value.2、Relative positioningRelative location is determined simultaneous tracking same GPS signals of several sets of the relative position between the receiver is a kind of method. Since the synchronous observation, the synchronization of many error signal obtained station is identical or similar (such as satellite clock error, error, the signal of the star alex atmospheric transmission error, etc.), can avoid or weaken these errors, obtain high relative position. Relative positioning, signal processing and data than absolute orientation is complex, relative positioning is the synchronization between baseline vector (station), and 3d coordinate need at least a spot for known to the rest of the each point coordinates. The static and dynamic positioning can position by relative positioning, such as earthdeformation measurement, ground control aerial photogrammetry, etc.In the dynamic positioning, often USES "difference", a GPS receiver will be placed on the base coordinate, known as the receiver in sports, all receivers carrier, according to the known synchronous control results, the positioning correct number starting position, in order to improve the real-time to positioning accuracy. This is based on a single point positioning and relative location of positioning mode.（三)、 Pseudorange method and the carrier phase methodGPS satellite positioning, according to the different signal processing, can divide again pseudorange method and the carrier phase method.1、Pseudorange methodThe positioning principle is simple. When positioning, receiver and the oscillation ofA satellite signal the same group (P yards range yards or C/A code), through delay and receiver receive signals, when two groups compared each other completely coincide (related to signal measured signals, namely for the delay in quantity, satellite signal transmission time with A series of modified times the speed of light, satellites and draw the oblique distance antenna phase center. If the four (or above), i.e. the distance can satellite stations calculate intersection method of location and clock error four unknown. Due to the wavelength m p 3.29λrange yards m A C 293=λ. To one percent of the estimated $yards range resolution, length of to 0.3 meters (P) and 3 meters (C/A code) the ranging accuracy. Therefore, the pseudorange accuracy is relatively low.2、The carrier phase methodThe carrier is a measure of carrier signal, measurements, determine the satellite signal and reference signal receiver, calculate the phase difference observation. Then the same principle and pseudorange method, the position of the station clock error, etc. The wavelength modulated symbol cm L 191=λ,cm L 242=λ, than much shorter wavelength of one percent, to $yards range resolution, estimating length reached 1.9 cm (P) and 2.4 L centimeters (C/A code) the ranging accuracy. In the measurement and precision air triangle measuring, high precision, often USES relative positioning method, the carrier phase to eliminate system error.The carrier phase method for measuring the complete phase observation data ϕfrom several parts:ϕϕϕϕφφ=-=+=++S R R N N I n tF 00~()() (2-1）Type: s ϕfor the first phase, the observational S,R ϕ for the position of the receiverobservation R phase, ~ϕfor the actual phase observations,0N for the whole cycle count,also called the whole cycle unknown, ()φInt for the actual observation time t the integer part, first observed 0t for the duration of zero, every moment, observation 0t by continuous accumulated through counter counts, called after the cycle count, ()φR F for the actual observation in the integer part, with high precision measurement.二、GPS positioning operation modeMainly includes GPS real-time GPS navigation positioning, afterwards (with) the dynamic positioning and used to measure the static or dynamic) relative orientation accurate.1 . GPS kinematic positioningGPS real-time navigation) is required (and observation data in the positioning of the moment, its main purpose is to navigation. AS mentioned above, the absolute positioning (single point positioning) by the us government's "SA" (choose usability) and "AS" (the electronic technology, the influence of deception by civil service standard of GPS level position precision of 100 meters. So many users using differential GPS system (CDGPS and WADGPS) to improve the precision. CDGPS pseudorange method and the users of the station standing range within 100 miles, precision for 5 ~ 10 meters. The carrier phase method CDGPS (also called RTK) standing and users in the station within range, 30 kilometers, the accuracy of cm. And WADGPS big scope is to create multiple known coordinates, standing and vice standing vice standing by data from receiving chain of error sources, after three corrections to users, communication WADGPS pseudorange method for positioning accuracy of about 1 ~ 3 meters, CDGPS superior. And stood and vice standing distance can reach over 1000 kilometers.2. Dynamic positioning postprocessingThis is a kind of carrier phase of dynamic positioning technologies. Usually a receiver is placed in the ground, and the other on the known a (or more) receiver in high-speed motion object, jr, afterwards synchronous according to the carrier phase difference between objects in motion relative to determine the location of known. Its characteristic is standing with users need to stand between the transmission of real-time data, the distance between the two is less restricted. But in high-speed motion of the object is how to determine the unknown 0N and the whole week jump problem is the technical difficulties. In recent years, the GPS technology of dynamic initialization OTF (again) greatly improve something comes after the practicability of the dynamic positioning. It can reach thecm-level positioning accuracy. Mainly applicable and low orbit satellite cm-level precision GPS satellite, aerial photogrammetry, airborne gravimetry, magnetic moment of determine the cm-level 3d coordinate of the airborne GPS technology.ed to measure the static（and dynamic) relative positioningStatic relative positioning using two sets of (or above), the GPS receiver respectively in each of the baseline endpoints, synchronous observation above four satellites 0.5 ~ 1 hour, baseline length in 20 kilometers. The baseline netted closed graph, constitute the whole event after adjustment, the precision can reach D5. Applicable to higher+1mm⋅ppmaccuracy of measurement and control of national land earth deformation monitoring, etc.Rapid static relative position in the central area with a base station, GPS receiver continuous tracking all visible satellites, in order to each other a receiver to the above five starting synchronous satellites, each 1 ~ 2 minutes to benchmark station starting at baseline length within 15 kilometers, with the benchmark stood for radiation center. Afterwards the processing precision can reach D+15, but poor reliability. Applicable to smallmm⋅ppmrange of control measure, engineering surveying and cadastration, etc.Accurate dynamic relative position in the zone, a GPS receiver with benchmark for tracking all visible satellites, another a receiver in starting sites for five first above synchronous satellites for 1-2 minutes and then keep track of all of the satellite, under the situation of continuous flow to the observation of the number of seconds, the observatory was starting to stand at the baseline length benchmark within 15 kilometers. Its characteristic is starting to keep each phase lock. In case of loss locks, must extend unlocked site observation time after 1 ~ 2 minutes to determine the unknownN and the0 whole cycle count cycle()φInt. Accurate dynamic relative positioning error in baseline can reach 1 ~ 2 cm long, suitable for engineering measurement circuit measurements and topography measurement, etc.第三节GPS application一、The GPS in engineering applicationIn surveying and mapping, GPS satellite positioning technology field has been used to establish the national geodetic measurement accuracy control network, determination ofthe earth; the dynamic parameters of the global To establish the land and sea, high-precision measurement datum of land and sea islands; measurement of surveying and mapping al Used for monitoring earth plate motion and the crustal deformation, Used for engineering measure, establish a city and the major means of engineering control network, Used for testing the aerospace photography instant camera position, only a very small ground control or no ground control chart, causing rapid aerial geographic information system, the global environment of remote sensing technology revolution.In the survey, using GPS technology to develop international league, establish the control of global network, provide high-precision geocentric coordinate, determination and refining geoid. So, for every Chinese department of surveying and mapping work, establish various measurement control network, provides the high plane and elevation 3d benchmarks.In the engineering survey, the application of static GPS positioning technology, relatively precise control network layont for mining cities, and the subsidence monitoring, oil dam deformation monitoring, high-rise buildings deformation monitoring, tunnel breakthrough measurement precision engineering etc. Encryption, using GPS surveying asbuilts of real-time dynamic positioning technologies (hereinafter referred to as RTK surveying and mapping) of scale topographic map and used in the construction of engineering construction lofting.In aerial photogrammetry, using GPS surveying workers also aerial technology field control measure, aerial electricity GPS navigation, airborne flying into the figure of the electricity, etc.On earth, GPS technology used in dynamic monitoring global and regional plate, plate motion of movement monitoring.The global positioning system (GPS) technology has been used in Marine measurement, underground terrain mapping and, moreover, the military defense, intelligent transportation, post and telecommunications, surveying, coal, oil, building and management of agricultural, meteorology, land, environmental monitoring, finance, public security departments and industry, in aerospace, test, physical detection, etc, also pose measurement are conducted the research and application of GPS technology.二、The GPS in scientific research applicationsThe global positioning system (GPS) used in mobile positioning and economical solutions when we directly transferred to customer service center, the mobile phone to check with customer directly short message (GPS positioning, minutes and seconds data format), if the use of electronic map software, general inter-city direct support of its inputGPS data, minutes and seconds, if use the function orientation LingTu days in Beijing, can use the new 5 special software of GPS positioning master manual input coordinates function orientation, this scheme is suitable for low frequency ZhaChe. Enhanced when customers can purchase special satellite positioning management host, it can not only be receiving many car positioning short message, and stored in computer automatic classification, each vehicle is to build a database of clicking a mouse button, finding a car, as long as all the locating records on target data will automatically switch to electronic map shows the location, click on the progress vehicle or the back button on electronic map can demonstrate in the form of automobile, each vehicle can take different names, facilitate management more cars, very convenient, more frequent query for car. Along with the rapid development of urbanization, urban scale expands unceasingly, to provide convenient and fast traffic intelligent transportation information service system, will be the future trend of development, In addition, navigation and positioning system based on mobile phone service, will become the trend for the people to pursue. In the future, all can move, will depend on the GPS. GPS will like mobile phones, Internet, for our life greatly influence. Therefore, the GPS will form the huge industry value chain, significant social and economic benefits.三、In the emerging field of application of GPSRTK technology is RTK network a milestone in the development of technology. This technique by several stations composed a network, and has a terminal. Each station by telecommunications network (fiber or DDN) will observation data, the central station to station by reference data and the model through a solution within the pressure-difference method is correct and its through GSM/GPRS public Internet user, users send according to the real-time difference correct information can obtain higher precision. Compared with the traditional RTK technology, network RTK distance between the base can be long, sichuan VRS seismological bureau standing space than average system construction of 60 kilometers, is the longest baseline once more than 90 kilometers. So, same area covered only need less station can be achieved, cost can be greatly reduced. At the same time, the concept of network calculation model makes more reliable. Traditional RTK system if a base, the user can occur in the base area in the implementation of homework, covering technology in network RTK nonexistent this problem, because the center will automatically according to the user's position and the operation condition of choosing base stations operations. With modern communication technology, the computer storage technology and the rapid development of space technology, measuring method and mode has achieved great progress. GPS network in the information revolution is RTK arises inthe new space data acquisition method. It combines modern technology of communication and information technology, computer network distributed storage and processing technology of virtual reference, standing technology (VRS) among, and modern geodetic technology. GPS network is more advanced technology of RTK integration, this system for the country's infrastructure provide conveniences. Also for "digital city provides real-time reliable source.2.译文全球定位系统第一节 GPS的原理概述一、全球定位系统GPSGPS(Navigation Satellite Timing and Ranging /Global Position System )，授时与测距导航系统/全球定位系统，简称GPS全球定位系统，是随着现代科学技术的迅速发展而建立起来的新一代卫星导航和精密定位系统。

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