《电子与通信技术专业英语》UnitⅢ-16

Chinese Translation of Texts
这24颗卫星有6个轨道面，或路径，这意味着每个轨道面有4个GPS卫星工作。 6个轨道面的每个之间呈60度隔开。所有这些轨道面都偏离赤道倾斜55度。
Chinese Translation of Texts
In order for GPS tracking to work, it is necessary to have both access to the Global Positioning System and have a GPS receiver (Fig.16-2). The GPS receiver is able to receive signals that are transmitted by GPS satellites orbiting over head. Once these satellite transmissions are received by the GPS receiver, location and other information such as speed and direction can be calculated.
• The Space Segment •ห้องสมุดไป่ตู้The Control Segment • The User Segment
Chinese Translation of Texts
全球卫星定位系统分为三个部分： • 空间部分 • 控制部分 • 用户部分
Chinese Translation of Texts
In order to measure the time delay between satellite and receiver, the satellite sends a repeating 1,023 bit long pseudo random sequence; the receiver constructs an identical sequence and shifts it until the two sequences match.
Chinese Translation of Texts
GPS使用21颗运行卫星，轨道中另外还有3颗后备卫星。全球定位系统利用由罗 克韦尔国际制造的导航卫星。每一个导航卫星约5米宽（包括延太阳能发电板的长 度），重量大约900公斤。
Chinese Translation of Texts
GPS satellites orbit the earth at an altitude of approximately 20,200km.Each GPS satellite has an orbital period of 11 hours and 58 minutes. This means that each GPS satellite orbits the Earth twice each day.
Chinese Translation of Texts
GPS为了进行跟踪，既要访问全球定位系统，还要有一个全球定位系统接收机 （图16－2）。全球定位系统接收机能收到上方绕轨道运行的全球定位系统卫星传 送的信号。一旦这些卫星传送的信号被全球定位系统接收机收到，位置及其他信息 如速度和方向等就能计算出来。
[ri'dʌndənt]
adj. 多余的
['seɡmənt]
n. 段；部分
['ɔ:bit]
n. & v. 轨道，常轨；绕轨道而行
New Words
delay ionosphere pseudo sequence multiple access encrypt
[di'lei]
n. & v. 耽搁，延迟
GPS uses twenty-one operational satellites, with an additional three satellites in orbit as redundant backup. GPS uses NAVSTAR satellites manufactured by Rockwell International. Each NAVSTAR satellite is approximately 5 meters wide (with solar panels extended) and weighs approximately 900Kg.
Chinese Translation of Texts
第16课 全球定位系统（GPS）
GPS是全球卫星定位系统。GPS使用卫星技术，能使地面终端确定它在地球上 的经度和纬度的位置。
Chinese Translation of Texts
GPS receivers do this by measuring the signals from three or more satellites simultaneously and determining their position using the timing of these signals （Fig.16-1）.
Chinese Translation of Texts
接收机包含有一个数学模型来计算这些信息的影响，卫星也传播一些相关的信 息以帮助接收机正确地估算传播速度。电离层等一些原因，会影响不同频率的无线 电波的速度, 双频接收机能测量它们对信号的影响。
Chinese Translation of Texts
Chinese Translation of Texts
为了测量卫星和接收机之间的时间延迟,卫星重复发送1,023字节长的伪随机序列； 接收机建立一完全相同的序列和移动它直到两序列匹配。
Chinese Translation of Texts
Different satellites use different sequences, which lets them all broadcast on the same frequencies while still allowing receivers to distinguish between satellites. This is an application of Code Division Multiple Access, CDMA.
[ai'ɔnəsfiə] n. 电离层
['sju:dəu] adj. 假的，冒充的
['si:kwəns] n. 序列，继起的事，顺序
['mʌltipl] adj. 多样的，多重的
['ækses] n. 通路，进入，使用之权
[in'kript] v. 加密，将……译成密码
Chinese Translation of Texts
Lesson 16 Global Positioning System (GPS)
GPS is the Global Positioning System. GPS uses satellite technology to enable a terrestrial terminal to determine its position on the Earth in latitude and longitude.
Chinese Translation of Texts
GPS的工作使用三边测量法。三边测量是指在未知点两侧有两个或两个以上的 已知点，与未知点呈虚拟的三角形，通过测量未知点到已知点的边长来确定未知点。
Chinese Translation of Texts
In the GPS system, the two known points are provided by two GPS satellites. These satellites constantly transmit an identifying signal. The GPS receiver measures the distance to each GPS satellite by measuring the time each signal took to travel between the GPS satellite and the GPS receiver.
Chinese Translation of Texts
GPS卫星的轨道离地区的距离约为20200公里。每个GPS卫星绕轨道一周的时 间为11小时58分钟。这意味着每一个GPS卫星每天绕地球两次。
Chinese Translation of Texts
These twenty-four satellites orbit in six orbital planes, or paths. This means that four GPS satellites operate in each orbital plane. Each of these six orbital planes is spaced sixty degrees apart. All of these orbital planes are inclined fiftyfive degrees from the Equator.
电子与通信技术专业英语
English on Electronic and Telecommunication Technology
Unit Ⅲ
03
Unit Ⅲ
Communication Technology
Lesson 16
Global Positioning System (GPS)
New Words
Chinese Translation of Texts
The receiver contains a mathematical model to account for these influences, and the satellites also broadcast some related information which helps the receiver in estimating the correct speed of propagation. Certain delay sources, such as the ionosphere, affect the speed of radio waves based on their frequencies, dual frequency receivers can actually measure the effects on the signals.
Chinese Translation of Texts
在GPS中，两个已知点由两个全球定位系统卫星提供。这些卫星不断传送一个 确定的信号。GPS接收机通过测量每一个信号在GPS卫星和GPS接收机之间传播的 时间来测量其距离。
Chinese Translation of Texts
GPS operates using trilateration. The GPS system is divided into three segments:
terrestrial latitude longitude trilateration redundant segment orbit
[tə'restriəl]
adj. 地球的，地上的
['lætitju:d]
n. 纬度
['lɔndʒitju:d]
n. 经度
[,trailætə'reiʃən] n. 【测】三边测量（术）
Chinese Translation of Texts
接收器同时测量来自三个或三个以上的卫星的信号，并通过这些信号的传播时 间来确定位置（图16－1）。
Chinese Translation of Texts
GPS operates using trilateration. Trilateration is the process of determining the position of an unknown point by measuring the lengths of the sides of an imaginary triangle between the unknown point and two or more known points.