Influence of GPS antenna phase center variation on precise positioning
卫星导航系统接收机原理与设计——之一(上)
Satelliteclassroom卫星课堂卫星导航系统接收机原理与设计——之一(上)+刘天雄第二十四讲概述 Receiver overview全球卫星导航系统简称GNSS(Global Navigation Satellite System)系统,由空间段SS(space segment)、地面控制段CS(control segment)以及用户段US(user segment)三个部分组成,其中用户段US就是咱们手里拿的接收机。
空间段SS的每颗导航卫星连续播发无线电导航信号,简称为SIS信号(Signals In Space),通常是L频段无线电信号,载波信号调制有周期数字码(periodic digital code)和导航电文(Navigation message),周期数字码又称为伪随机噪声测距码,简称PRN(pseudo-random noise code)码。
卫星导航系统定位的基本原理是单向到达时间测距,简称TOA(Time Of Arrival)原理,接收机通过解调导航信号的电文得到卫星的位置坐标,通过测量导航信号从卫星到接收机的传播时间来测距,以导航卫星为球心,信号传播的距离为半径画球面,用户接收机一定在球面上,当接收机分别测量出与四颗导航卫星之间的距离时,四个球面相交于一个点,即用户接收机的位置坐标,如图1所示。
如果是导航仪,接收机根据位置坐标和数字地图的映射关系,可以把定位结果映射到数字地图上,在显示屏上给出地址信息。
根据不同的应用场景,卫星导航接收机可以设计成多种不同状态,从单频(single-frequency)到多频(multi-frequency)、从单系统(single -constellation)到多系统(multi-constellation)、从专业测量型(survey)到一般车载导航型(automotive applications),设计接收机时还需要考虑信号带宽(signal bandwidth)、信号调制(modulation)、伪码速率(code rate)等技术指标,权衡工作性能(performance)、成本(cost)、功耗(power consumption)以及自主性(autonomy)等要求。
全球定位系统(GPS)术语及定义
全球定位系统(GPS)术语及定义全球定位系统(GPS)术语及定义【中华人民共和国国家标准GB/T 19391-2003 】2004-12-24 5:55:151范围本标准规定了全球定位系统(GPS)常用术语及定义。
本标准适用于GPS专业范围内的各种标准的制定、各类技术文件的编制,也适用于科研、教学等方面。
2通用术语2.1全球定位系统global positioning system(GPS)导航星navigation by satellite timing and ranging(NA VSTAR)一种卫星导航定位系统。
由空间段、地面控制段和用户段三部分组成.为伞球用户提供实时的三维位置、速度和时间信息。
包括主要为军用的精密定位服务(PPS)和民用的标准定位服务(SPS)。
2.2全球导航卫星系统global navigation satellite system(GLONASS)一种全球卫星导航定位系统:为全球用户提供实时的三维位置、速度和时间信息。
包括军用和民用两种服务。
2.3伽利略系统Galileo system一种民用全球卫星导航系统;2.4全球导航卫星系统global navigation satellite system(GNSS)由国际民航组织提出的概念。
GNSS的最终目标是由多种民用卫星导航系统组成,向全球民间提供服务。
并将由多国民间参与运行和控制的卫星导航系统。
GNSS也已经为国际海事组织(IMO)所接受。
欧洲的GNSS计划分为两个阶段,即GNSS-1和GNSS-2。
GNSS-1为EGNOS(欧洲地球静止轨道卫星导航重叠服务)系统,GNSS-2为Galileo(伽利略)系统。
2.5静地星/定位星系统Geostar/Locstar system一种卫星定位系统,利用两颗地球轨道静止卫星双程测距而实现定位功能,兼有简短报文通信能力。
2.6海军导航卫星系统navy navigation satellite system(NNSS)子午仪Transit是1960年由美国研制的卫星导航系统,为固定用户或低动态用户提供不连续定位信息。
GPS天线高量算
Antenna Phase CentreContents:Physical Phase CentreElectrical Phase CentreAntenna Reference Point, Bottom of Antenna, Bottom of Pre-amplifierExamplePhysical Phase CentreThe definition of the Physical Phase Centre (PPC) is commonly defined by the location of the chipset within the antenna. Neither the electrical phase centre nor the physical phase centre are points that can be physically measured to, so the offset of the physical phase centre from a external point on the antenna must be known and is commonly referenced to theBase/Bottom of Antenna (see below).Using the correct phase centre offsets becomes very important when different antenna types are used in a survey. When using GPSnet base stations it is very likely that your antenna will be different from the antenna at the base stations. The difference in phase centre offsets between GPSnet base station antenna and your antenna need to be included in your GPS data processing. Normally this is done by your processing software.The antenna heights of all GPSnet base stations are measured vertically from the physical phase centre to the Antenna Reference Point (ARP) for each antenna, which is usually the base of the antenna mount. This height is the one given in the RINEX file header. The offset from the ARP to the physical phase centre is then added to the ARP height (usually in the processing software) to give the height of the phase centre above datum. For all the antenna in the GPSnet network the bottom of antenna is the ARP, however, that does not account for the phase centre offsets from the ARP.The main phase centre offset component is vertical (up) but there are also small horizontal offsets (north and east) that can be applied. There are actually two phase centres in an antenna – one for the L1 frequency and the other for L2, and each phase centre has a different offset.Electrical Phase CentreThe L1 and L2 electrical phase centre are the theoretical points in space where the L1 carrier phase is fixed and L2 received "on average." The actual location where this signal is received, however, varies as a function of the direction of the incoming GPS signal, and hence an averaging process is required. An Antenna Reference Point (ARP) such as Bottom of Antenna Mount (BA) is a specified physical point on the antenna. For any given GPS antenna, the electrical phase center will change with the changing direction of the signal from a satellite. Ideally, most of this phase center variation depends on satellite elevation.The relative spatial relationship between these two points is determined via a calibration process in a laboratory-type environment. This process involves collecting and processing several hours of GPS data, and it involves several assumptions about antenna characteristics.The National Geodetic Survey (NGS) has calibrated many antenna and has determined the average spatial relationship between these two points for each of several classes of antenna. See: National Geodetic Survey Antenna CalibrationNGS provides spatial co-ordinates for both the L1 phase centre and the ARP, as different GPS software packages may use one or the other of these points or possibly even some other reference point. GPS post-processing software such as Trimble Geomatics Office takesthe physical phase centre as a reference point then applies elevation dependant electrical phase centre corrections during base line processing.The actual observation point on a GPS antenna is called the Electrical Phase Centre (EPC). The location of this phase centre is represented by a mean constant offset, from the physical point on a GPS antenna known as the Antenna Reference Point (ARP), and an additional variable offset that is dependant on the transmitting satellite's elevation.The properties of the electrical phase centre are different for every type of antenna. Importantly the electrical phase centre can be modelled provided you know the antenna type. Agencies like NGS encourage GPS companies to provide the Antenna Reference Point such as Bottom of Antenna Mount (BA) for use by their processing software.Antenna Reference Point, Bottom of Antenna, Bottom of Pre-amplifierThe definition of the Antenna Reference Point (ARP) is determined by an actual external point that can be physically measured to. Most commonly this point will be the Bottom of Antenna (BA) and also commonly referred to as the Bottom of Pre-amplifier. An example of the Antenna Reference Point is where the tribrach and antenna mount coincide.Refer to the example below.Example(Acknowledgments - Geoscience Australia, Ashtech, Ordnance Survey UK, National Geodetic Survey US)。
一种双频喇叭馈源的相位中心分析
一种双频喇叭馈源的相位中心分析黎娜【摘要】The multiple-mode conic horn is a high-efficiency antenna which is widely used as the feed of reflectors. Phase centers of the dual-band multiple-mode conic horn at receive and transmit frequency are not superposed, so the ascertainment of its phase center and location in the reflector system has unneglected influence on the performance of the reflector system. The definition of the phase center of the antenna is proposed and the phase centers of the dual-band multiple-mode conic horn at receive and transmit frequency are calculated. Finally the optimal location of the feed in the offset reflector antenna is confirmed by the analysis and optimization.%多模圆锥喇叭天线是一种应用较广的高效率喇叭天线,它被广泛应用于反射面初级馈源.双频多模圆锥喇叭天线在收发两个频率处的相位中心是不重合的,当其作为反射面馈源时,其相位中心及安放位置的确定对于反射面天线的性能有着不可忽视的影响.从天线相位中心的定义出发,计算了双频多模喇叭天线在收发频率处的相位中心,并对该天线在偏置反射面系统中的安放位置进行了分析,确定了馈源的最佳安放位置.【期刊名称】《现代电子技术》【年(卷),期】2012(035)007【总页数】4页(P98-100,104)【关键词】多模圆锥喇叭;双频段;反射面馈源;相位中心【作者】黎娜【作者单位】西安机电信息技术研究所,陕西西安710065【正文语种】中文【中图分类】TN820.120 引言反射面天线的馈源不仅要求具有特定的幅度方向图,而且对相位方向图也有要求,要求馈源辐射球面波有确定的相位中心,只有当馈源的相位中心与反射面的焦点重合时,天线才具有最大的口径利用效率和良好的方向图波瓣特性[1]。
地理信息科学专业英语书后单词
Spatial interpolation 空间插值 standard query language(SQL)标准化查询语言
Polygon 多边形 proximity analysis 邻近域分析
Data structures 数据结构 information retrieval 信息检索
Topological modeling 拓扑建模 network analysis网络分析
Overlay 叠置 data output 数据输出
7、remote sensing 遥感 பைடு நூலகம் sensor 传感器
Electromagnetic radiation 电磁辐射 radiometer 辐射计
Electro-optical scanner 光学扫描仪 radar system 雷达系统
high resolution visible(HRV)sensors 高分辨可视成像传感器
Charge-coupled devices (CCDs)电荷耦合器件
panchromatic(PLA)全色 multispectral(MLA)多波段
WFI(Wide Field Imager)广角成像仪 earth observing system(EOS)地球观测系统
CBERS(China-Brazil Erath Resources Satellite)中巴地球资源卫星
IRMSS(Infrared Multispectral Scanner) 红外多光谱扫描仪
Disaster management 灾害管理 public health 公共卫生
GPS专业术语
4.9惯性导航系统inertial navigation system(INS)利用惯性仪表(陀螺仪和加速度计)、参考方向和初始位置来测量载体运动方向、速度【中华人民共和国国家标准GB/T 19391-2003 】1 范围本标准规定了全球定位系统(GPS)常用术语及定义本标准适用于GPS专业范围内的各种标准的制定、各类技术文件的编制,也适用于科研、教学等方面2 通用术语2.1全球定位系统global positioning system(GPS)导航星navigation by satellite timing and ranging(NAVSTAR)一种卫星导航定位系统由空间段、地面控制段和用户段三部分组成.为伞球用户提供实时的三维位置、速度和时间信息包括主要为军用的精密定位服务(PPS)和民用的标准定位服务(SPS)2.2全球导航卫星系统global navigation satellite system(GLONASS)一种全球卫星导航定位系统:为全球用户提供实时的三维位置、速度和时间信息包括军用和民用两种服务2.3伽利略系统Galileo system一种民用全球卫星导航系统;2.4全球导航卫星系统global navigation satellite system(GNSS)由国际民航组织提出的概念GNSS的最终目标是由多种民用卫星导航系统组成,向全球民间提供服务并将由多国民间参与运行和控制的卫星导航系统GNSS也已经为国际海事组织(IMO)所接受欧洲的GNSS计划分为两个阶段即GNSS-1和GNSS-2GNSS-1为EGNOS(欧洲地球静止轨道卫星导航重叠服务)系统,GNSS-2为Galileo(伽利略)系统2.5静地星/定位星系统Geostar/Locstar system一种卫星定位系统,利用两颗地球轨道静止卫星双程测距而实现定位功能兼有简短报文通信能力2.6海军导航卫星系统navy navigation satellite system(NNSS)子午仪Transit是1960年由美国研制的卫星导航系统,为固定用户或低动态用户提供不连续定位信息注:已于l997年12月31日关闭2.7国际GPS动力学服务international GPS geodynamics service(IGS)国际大地测量协会于1994年创立的国际GPS研究服务机构它负责向世界各国的GPS用户提供精密的星历、地球旋转参数、全球GPS跟踪网数据等多种信息2.8GPS空间段GPS space segment指GPS的空间星座它按设计由分布在6个轨道平面上的24颗导航卫星组成,卫星向地球方向广播含有测距码和数据电文的导航信号2.9GPS地面控制段GPS ground control segment指GPS的地面监测和控制系统,它包括主控站、卫星监测站和上行信息注入站(又称地面天线)以及把它们联系起来的数据通信网络2.10GPS用户段GPS user segment指各种GPS用户终端其主要功能是接收卫星信号,提供用户听需要的位置、速度和时间等信息2.11Block ⅠⅡ,ⅡA,ⅡRⅡR-M,ⅡFⅢ卫星Block Ⅰ,Ⅱ,ⅡA,ⅡR,ⅡR-M,ⅡF,Ⅲsatellites指GPS的各代卫星的名称Block Ⅰ是原型卫星;BlockⅡ和ⅡA是目前的基本工作卫星;Block ⅡR和ⅡR-M是正在发射的替补卫星;Block ⅡF是后继卫星 Block Ⅲ是在规划中的2010年以后发射的卫星2.12伪卫星pseudolite设立在地面上的GPS信号发射站它发播与真实的GPS卫星相似的信号可在近距离内起到和GP5卫星类同的作用2.13星历ephemeris描述天体的空间位置的轨道参数2.14GPS卫星星历GPS satellite ephemerisGPS卫星星历一共包含16种数据,它们分别是历元、在历元上的6个卫星轨道参数以及用于在历元之后修正轨道参数的9个系数2.15广播星历broadcast ephemeris卫星播发的电文中所包含的本颗卫星的轨道参数或卫星的空间坐标2.16精密星历precise ephemeris由若干个不属于GPS系统的卫星跟踪站获得的测量值,经事后处理计算出的卫星轨道参数供事后精密定位使用2.17历书almanacGPS卫星电文中包含的所有在轨卫星的粗略轨道参数2.18载频L1、L2、L5 carrier L1,L2L5L1、L2为GPS卫星所发射信号的载频,L1为1575.42MHz,L2为1227.60MHzL5为GPS卫星将增发的民用信号的载频,预定为117**5MHz2.19历元epoch指一个时期和一个事件的起始时刻或者表示某个测量系统的auot cad参考日期注:在GPS术语中两种概念都使用2.20伪随机噪声码pseudo random noise(PRN)code一种具有与白噪声类似的自相关特性确定的码序列GPS信号中采用了伪随机噪声编码技术,以产生码分多址(CDMA),直接宇列扩频和伪距测量功能2.21粗/捕获码coarse/acquisition codeC/A码C/A code用于调制GPS卫星L1载频信号的民用伪随机码2.22精码precise codeP码P code曾经用于调制GPS卫星L1和L2载频信号的伪随机码2.23P(Y)码P(Y)codeY码Y codeGPS卫星用于调制L1和L2载频信号的军用伪随机码,由P码与加密码W模2相加而成由于Y码仍然保持着P码的码速率,因此也称作P(Y)码2.24精度因子dilution of precision(DOP)描述卫星的几何位置对误差贡献的因子GPS的误差为测距误差与精度因子之乘积2.25几何精度因子geometrical dilution of precision(GDOP)表征卫星几何位置布局对GPS三维位置误差和时间误差综合影响的精度因子2.26位置精度因子positional dilution of precision(PDOP)表征卫星几何位置布局对GPS三维位置精度影响的精度因子2.27高程精度因子vertical dilution of precision(VDOP)表征卫星几何位置布局对GPS高程定位精度影响的精度因子2.28平面位置精度因子horizontal dilution of precision(HDOP)表征卫星几何位置布局对GPS平面位置精度影响的精度因子2.29时间精度因子time dilution of precision(TDOP)表征卫星几何位置布局对GPS时间精度影响的精度因子2.30捕获acquisition用户设备对接收到的GPS卫星信号完成码识别、码同步和载波相位同步的处理过程2.31重捕re-acquisitionGPS接收机因信号遮挡等原因短时间失锁后重新捕获信号的过程一般很快便能完成2.32跟踪tracking对捕获到的GPS卫星信号继续保持码同步和载波相位同步的过程2.33码相位跟踪code phase trackingGPS接收机通过对GPS卫星信号的C/A码或P(Y)码的码相位进行跟踪,以获得GPS伪距测量值的过程2.34载波相位跟踪carrier phase trackingGPS接收机通过对GPS卫星信号的载波相位的跟踪,以获得载波相位测量值的过程2.35载波相位平滑carrier phase smoothing在GPS接收机中利用积分载波相位测量值,以减小由码相位跟踪噪声造成的误差的方法2.36周跳cycle slips在GPS接收机进行载波相位跟踪时,因某种原因产生的整数载波周期跳变2.37伪距pseudorange由GPS接收机测出的卫星信号传播时间而计算出的卫星与接收天线相位中心间的距离2.38距离变化率range rate用测量GPS卫星载波的多普勒频移求得的伪距变化的速率2.39选择可用性selective availability(SA)是美国人为地将误差引入卫星时钟和星历数据中,以降低GPS标准定位服务(SPS)精度的人为措施注:该措施从1990年3月开始实施,2001年5月1日停止使用2.40完好性integrity当无线电导航系统不应当用于导航时向用户及时发出警告(信息)的能力GPS 系统有一定的完好性措施,但对一些应用系统目前的完好性还不够2.41反欺骗anti-spoofing(A-S)GPS卫星信号中用加密码W与P码相叠加使之变为Y码的措施,用于精密定位眼务(PPS)只有具有解密能力的接收机才能利用精密定位服务2.42标准定位服务standard positioning service(SPS)由GPS的C/A码所提供的公开的民用服务2.43精密定位服务precise positioning service(PPS)由GPS的P(y)码所提供的保密服务,仅供美国及其盟国军用或经特许的其他用户使用2.44接收机自主完好性监测receiver autonomous integrity monitoring(RAIM)接收机利用冗余GPS卫星的伪距测量信息以判定GPS系统完好性的方法它能判断可见卫星中是否有卫星出现故障或哪一颗卫星发生了故障并将其排除在导航解之外2.45飞机自主完好性监视airplane autonomous integrity monitoring(AAIM)利用飞企业资产负债表表格下载机上各种导航设备的冗余信息辅助GPS接收机,以提高GPS完好性的一种技术2.46GPS完好性通道GPS integrity channel(GIC)以由多个地面GPS卫星监测台组成的网为基础,提高GPS星座完好性的技术2.47故障检测和排除fault detection exclusion(FDE)在RAIM中,利用冗余GPS卫星的伪距测量信息,具体地判定某一颗卫星不可用而将其从求解组合中排除不用的方法注:当可见卫星为6颗以上时才能作故障检测和排除2.48GPS监测站GPS monitor station在GPS地面控制段中用以对GPS星座的所有卫星进行跟踪测量的设施全球一共设有5个所有监测站收集到的数据传送到主控站,在那里解算出卫星星历和时间的修正参数,然后上行加载到卫星上2.49主机板original equipment manufacture(OEM);engine board是GPS接收机的核心部件包括RF、数字通道、处理器和定位解算软件在OEM基础上,根据不同用户的需求,加上不同的人机界面、天线和外壳结构,可以做成适合不同需要的GPS用户没备2.50C/A码GPS接收机C/A code GPS receiver利用GPS的C/A码进行导航定位的接收机2.51P(Y)码GPS接收机P(Y)code GPS receiver利用GPS的P(Y)码进行导航定位的接收机2.52单频GPS接收机single frequency GPS receiver只能接收GPSL1载频信号而进行导航定位的接收机2.53双频GPS接收机dual frequency GPS receiver能够接收GPS L1、L2信号而进行导航定位的接收机2.54无码GPS接收机codeless GPS receiver在不知道P(Y)码序列的条件下,采用某种信号处理技术获得GPSL1和L2双频信号的测量值,从而具有电离层延迟校正能力的民用双频GPS接收机2.55软件无线电GPS接收机software radio GPS receiver将经天线接收和直接放大后的GPS卫星信号送入高速模/数变换器,其后的全部处理过程由通用数字信号处理器完成的GPS接收机2.56导航型GPS接收机navigational GPS receiver能在动态条件下提供实时定位及其他数据并具有导航功能的GPS接收机2.57测地型GPS接收机geodetic GPS receiver能够提供卫星信号原始观测值用于高精度测量的接收机2.58GPS/GLONASS兼用接收机GPS/GLONASS dual-used receiver能够同时接收GPS卫星和GLONASS卫星信号进行导航定位的接收机2.59测姿型GPS接收机attitude-determination GPS receiver用以测量载体方向、横滚和俯仰等参数的GPS接收机通常由多个GPS接收天线、OEM和相应的处理器组成2.60测向型GPS接收机GPS azimuth-determination receiver用以测量载体方向等参数的GPS接收机,通常由双天线、OEM和相应的处理器组成2.61授时型GPS接收机time transfer GPS receiver专用于精确时间(GPS时或UTC时间)发布的GPS接收机有时还同时输出高稳定度的频率授时精度可以达到或超过40ns2.62定时校频GPS接收机GPS time/frequency receiver同时产生GPS标准秒信号和基准频率的GPS接收机用于对用户的时钟和频率源进行定时和校准2.63单通道GPS接收机single channel GPS receiver采用单个硬件通道,按照一定的时序实现对多颗卫星信号的跟踪并完成定位功能的老式GPS接收机2.64多通道GPS接收机multichannel GPS receiver一个包含多个并行通道的GPS接收机每个通道都能独立连续跟踪一颗或一颗以上卫星2.65GPS数字接收机GPS digital receiver从中频开始进行数字量化处理的GPS接收机2.66GPS模拟接收机GPS analog receiver载波环和码环采用模拟电路实现的老式GPS接收机2.67差分GPS接收机differential GPS receiver能够接收由差分基准站的数据链路发射的差分修正数据,而进行差分导航定位的GPS用户设备,一般包括数据链信号接收机和能利用差修正信息的GPS接收机2.68GPS接收机应用模块GPS receiver application module(GRAM)是一种标准化的美国军用GPS用户设备模块,用于确保军用GPS用户设备的安全性、共用性和互换性2.69GPS天线设备档案表格相位中心GPS antenna phase center指GPS天线的电气中心其理论设计应与天线的几何中心一致2.70GPS接收机噪声GPS receiver noiseGPS接收机噪声是由接收机内部热噪声、通道间的偏差和量比误差等引起的测距和测相误差的综合表征2.71GPS微带天线GPS microstrip antenna一种GPS接收机天线类型由粘接在基板上的特殊设计和精确量裁的金属箔构成2.72冷启动cold startGPS接收机在不知道星历、历书、时间和位置的情况下开机,需要较长时间才能正常定位2.73温启动warm startGPS接收机在不知道星历,但存有历书、时间和位置的情况下开机,达到正常定位的时间比冷启动短2.74热启动hot startGPS接收机在存有星历、历书、时间和位置的情况下开机达到正常定位的时间比温启动短2.75均方根误差root mean square(RMS)表明GPS观测值数据质量的参数,其值越小数据质量越好2.76用户距离误差user range error(URE)用户测量所得的伪距与至卫星真实距离的误差,用均方根值来规定2.77用户等效距离误差user equivalent range error(UERE)根据各种误差源听求得的对用户至卫星距离测量误差的估值2.78GPS导航电文GPS navigation message是由GPS卫星播发给用户的描述卫星运行状态与参数的电文,包括卫星健康状况、星历、历书,卫星时钟的修正值、电离层时延模型参数等内容,以50bps 速率播发2.79转换字hand over word(HOW)GPS导航电文中的转换字载有时间信息,用于在P(Y)码接收机中辅助从C/A 码跟踪状态转换到P(Y)码跟踪状态2.80Z-计数Z-countGPS卫星时钟时间在GPS导航电文中位于每个子帧的第二个转换字(HOW)之前,用29位二进制数表示,单位为1.5s,一个Z-计数为6s2.81差分GPS differential GPS(DGPS)一种提高GPS定位和定时精度的技术在已知点上设置GPS基准接收机,根据由此获得的GPS测量误差产生误差修正量,实时或事后提供给差分GPS用户设备,使用户设备接收并利用修正量以提高其定位精度2.82差分基准站differential reference station差分站differential station设在已知坐标点上的GPS基准接收机连续观测视界内的卫星,产生差分修正量再利用数据链发射台向差分GPS用户设备发送差分修正信息这种固定站称为差分基准站2.83局域差分GPS local area DGPS(LADGPS)用于提高局部区域的GPS定位精度的实时差分GPS系统2.84局域增强系统local area augmentation system(LAAS)利用VHF数据链的局域差分GPS系统,它同时提高GPS定位精度和完好性为飞机精密进近服务2.85位置差分GPS position differential GPS以差分基准接收机提供的位置误差作为修正量的局域差分GPS,它要求基准站GPS接收机和用户接收机使用相同的卫星组进行定位解算2.86伪距差分GPS pseudorange differential GPS以差分基准接收机产生的视界内各颗GPS卫星的伪距误差及其变化率作为修正量的局域差分GPS它不要求基准接收机和用户接收机使用相同的星组2.87载波相位差分GPS carrier phase differential GPS利用基站GPS接收机和用户GPS接收机对多颗卫星信号的载波相位和码伪距的观测量,进行双差分和其他处理,以使用户获得厘米甚至毫米级定位精度的一种相对定位技术2.88实时动态测量系统real time kinematic(RIK)survey system利用数据链将基站GPS接收机的载波相位和码伪距观测量传送给用户,用户接收机采用双差分以及其他处理快速解算出载波整周多值性,以实现动态高精度的实时定位系统2.89EUROFIX系统EUROFIX system以罗兰C作为数据链的局域差分GPS系统2.90连续工作基准站continuously operating reference stations(CORS)互联网差分iso9001质量手册范本GPS internet differential GPS由美国大地测绘局(NGS)、国家海洋和大气局(NOAA)联合建立的GPS增强系统它通过互联网和电话数据包服务,收集来自分布在全国的几百个基准站的码距离和载波相位数据,经中心站处理后再通过互联网,提供给用户,支持GPS 非导航用户和后处理应用,提高GPS定位精度2.91中波数据链差分differential using medium frequency data link利用中波数据链的局域差分GPS2.92海用差分GPS maritime DGPS是一种中波数据链差分GPS用已有的或增强的海用无线电信标台发射信号的副载波作数据链,同时提高水上用户的定位精度和完好性2.93调频数据链差分differential using FM data link利用调频广播副载波作数据链的局域差分GPS2.94全国差分GPS nationwide differential GPS(NDGPS)利用与海用差分GPS同样的体系结构由许多基准站组成,并连同已有的海用差分站,组成覆盖全美国的系统,用于提高GPS定位精度与完好性,为陆上和水上用户服务2.95广域差分GPS wide area DGPS(WADGPS)利用大范围地面分布的GPS基准站收集GPS卫星的数据把伪距误差分解成分量,在整个区域对每一分量进行估计形成修正量,将这些修正量实时传送给GPS用户设备一般由主控站、多个基准站、差分信号播发站、数据通信网络和用户设备组成可用相对较少的基准站提高较广区域的GPS定位精度2.96广域增强系统wide area augmentation system(WAAS)由美国研制的,利用广域差分技术、卫星完好性监测技术和GPS导航信号转发技术,用地球静止卫星作为数据链以GPS L1载频播发这些增强信息用户使用相宜的接收机系统WASS提高GPS的完好性、精度和可用性主要为美国民用航空服务目标是使GPS在整个美国达到飞机I类精密进近的水平2.97欧洲静地星导航重叠服务European geostationary navigation overlay service (EGNOS)欧洲发展的与WAAS相类似的系统和WAAS的主要差别是:它将同时增强GPS和GLONASS系统,覆盖整个欧洲及周边地区2.98多功能交通卫星星基增强系统MTSAT satellite based augmentation system (MSAS)由日本发展的,与WAAS十分类似的系统利用多功能交通卫星(MSAST)播发数据,覆盖日本及其周边洋区2.99星基增强系统satellite based augmentation system(SBAS)利用地球静止轨道卫星播发差分修正及其他信息,以提高卫星导航用户的精度及其性能的广域增强系统2.100陆基增强系统ground based augmentation system(GBAS)利用地面发射台播发差分修正及其他信息以提高卫星导航刚户精度机其他性能的局域增强系统2.101机上增强系统aircraft based augmentation system(ABAS)航空器上利用其他系统获得信息以增强卫星导航用户终端的(定位)性能,或利用它们之间的组合方式共同形成性能增强的导航信息2.102联合精密进近着陆系统joint precision approach and landing system(JPALS)是美国军方正在研制的利用军用信号的差分GPS着陆、着舰系统2.103舰载相对GPS shipboard relative GPS是联合精密进近着陆系统作舰载飞机着舰时的特殊应用方式,为飞机提供相对于军舰的位置2.104GPS现代化GPS modernization为提高GPS系统性能而正在抉行的计划,包括在GPS卫星发射的L2载频上增加调制民用码,增加发射L5载频的民用信号,把军用与民用信号频谱分隔开,在L1、L2上增发军用的M码、增大卫星发射功率和改善地面控制段等措施2.105广域GPS强化wide area GPS enhancements(WAGE)利用GPS卫星同时发播整个星座的伪距修正信息,以提高GPS系统精度的一种方法2.106GPS精度改善创新GPS accuracy improvement initiative(AⅡ)是美国为提高GPS系统精度而正在进行的一项计划,该计划包6s管理检查表括把美国影像和地图绘制局(NIMA)的GPS卫星监测站并入现有监视网络,重新设计主控站GPS中的卡尔曼滤波器以及改善对GPS卫星上行注入方式与能力等三项改善地面控制段的措施2.1073P计划3P program是美国对GPS导航战计划的别称,包括:● 保护(美国及其盟国)在战场上的GPS军事服务;● 防止敌对方对GPS服务的利用;● 维持在战场区域以外的GPS民用服务注:由于保护(protection)、防止(prevention)、维持(preserve)的英文字头均为P,故称为3P2.108导航战navigation warfare(NAVWAR)美国于1996年开始执行的一项军事计划,其目的是提高GPS军用接收机的抗干扰能力,使美军具有在区域的基础上停止GPS民用接收机工作的能力,甚至包括停止其他卫星系统工作的能力2.109GPS接口控制文件GPSICD-200GPS接口控制文件是—个美国政府文件,包括用户与GPS卫星间接口的完整的技术说明2.110海用差分GPS电文格式RTCM SC-104 DGPS message format美国海用无线电技术委员会(RTCM)104专门委员会(SC-104)制定的GPS 差分数据电文格式,在世界范围得到推广应用2.111NMEA-0183美国国家海洋电子协会制定的海用电子设备接口标准及数据格式,许多GPS接收机采用这种标准作为一种数据输入输出格式3 测量特性术语3.11984世界大地坐标系world geodetic system 84WG84坐标系WG84 coordinate system由美国国防部在与WGS72相应的精密星历系统NSWC-9Z-2基础上采用1980大地参考系和BIH1984.0系统定向所建立的一种地心参考系3.2模糊度(多值性)ambiguity当一个接收机对卫星进行连续观测,为重建载波相位的伪距观测值,其中所包含的侍解未知整周数称为整周模糊度值3.3天线高antenna height观测时接收机天线相位中心至测站中心标志面的高度3.4观测时段observation session观测站上开始接收卫星信号到停止接收,连续观测的时间间隔称为观测时段简称时段3.5同步观测simulateous observation两台或两台以上接收机同时对同一卫星进行的观测3.6独立观测环independent observation loop由非同步观测获得的基线向量构成的闭合环3.7单差解single difference solution对两个不同观测站GPS接收机同步观测同一卫星载波相位观测值进行求差的数据处理方法可以消除或削弱GPS卫星钟差、轨道误差、电离层时延和对流层时延3.8双差解double difference solution对两个不同观测站GPS接收机同步观测两颗卫星听得的单差进行求差的数据处理方法,可以消除GPS接收机钟差3.9三差解triple difference solution对两个不同观测站GPS接收机同步观测两颗卫星所得的双差在不同历元进行求差的数据处理方法,可以消除整周模糊度3.10数据剔除率percentage of data rejection删除的观测值个数与应获取的观测值个数的比值3.11扼流圈天线choke ring antenna一种根据L1、L2频率值精心设计的带有多路径抑制槽、可以同时消除L1、L2多路径效应的测量型GPS接收机专用天线,一般用于高精度GPS测量3.12RATIO值RATIO反映GPS整周模糊度解算结果可靠性的参数,其结果取决于多种因素用次最小RMS与最小RMS的比值来表示3.13组合观测值combinative observation由L1、L2载波相位观测值通过一定的数学运算得到的观测值3.14宽巷观测值wide lane observation由L1-L2得到的组合观测值,其波长为86.19cm,有利于求解整周模糊度3.15窄巷观测值narrow lane observation由L1+L2得到的组合观测值,具有比L1、L2都小的观测噪声3.16RINEX格式receiver independent exchange format是GPS原始观测数据的一种通用的存储格式,是ASCII码文本文件,一般由观测数据文件、导航数据文件、气象数井下作业工初级工据文件三种,有特定的文件命名方式其最新版已包括GLONASS数据3.17参考站reference station在一定的观测时间内一台或几台接收机分别固定在一个或几个测站上一直保持跟踪观测卫星,其余接收机在这些测站的一定范围内流动设站作业,这些固定测站就称参考站3.18流动站roxing station在参考站的一定范围内流动作业的接收机所设立的测站3.19GPS静态定位测量static GPS positioning通过在多个测站上进行若干时段同步观测,确定测站之间相对位置的GPS定位测量3.20GPS快速静态定位测量fast static GPS positioning利用快速整周模糊度解算法原理所进行的GPS静态定位测量3.21永久性跟踪站permanent tracking station长期连续跟踪接收卫星信号的永久性地面观测站3.22单基线解single baseline solution在多台GPS接收机同步观测中每次选取两台接收机的GPS观测数据解算相应的基线向量3.23多基线解multi-baseline solution从m(m>3)台GPS接收机同步观测值中,由m-1条独立基线构成观测方程统一解算m-1条基线向量3.24航摄GPS测量参考点reference point for GPS photographic surveying航摄GPS测量中计算动态基线的起算点3.25偏心向量eccentric vector飞机上GPS天线相位中心对航摄仪镜头中心的偏移向量3.26初始基线initialization baseline航摄GPS测量开始之前,参考点和飞机上GPS天线相位中心之间的距离3.27闭合基线closure baseline航摄GPS测量结束后,参考点和飞机上GPS天线之间的距离3.28运动测量kinematic surveying只需短时间的观测资料的连续差分载波相位测量的一种方式操作常数包括确定一已知基线或从一已知基点开始最少跟踪四颗卫星—个接收机应固定安装在一控制点上(已知点上)其他接收机在被测点间移动3.29单点定位point positioning一台接收机单独模式下的地理定位3.30绝对定位absolute positioning定位方式之一,定出某点在某一个特定坐标系上的位置,该坐标系通常是地心坐标系3.31相对定位relative positioning指通过两个站的接收讥同时司步地观测相同卫星来确定两个站的相对位置差的过程这种技术可以消掉两个站的共同误差,比如卫星钟差和预报星历误差,传播延迟等3.32静态定位static positioning一种接收机处在静止或几乎静止情况下的定位3.33动态定位dynamic positioning按时间顺序求解运动中的接收机的坐标每一组坐标只由一次信号取样来确定,且通常进行实时解算4 导航特性术语4.1汽车GPS导航系统in-vehicle GPS navigation system汽车GPS导航系统是以车载GPS接收机为基础,结合其他导航手段获得载体位置数据,并与导航地图数据库相匹配。
卫星导航术语速查(英汉对照)
Gold codes or Gold sequences
Gold码 或Gold 序列
GPS modernization
GPS现代化
GPS Time (GPST)
GPS时
gravitational potential
重力势能
Greenwich Apparent Sidereal Time (GAST)
伪距增量
destructive interference
破坏性干扰
differential corrections
差分改正
differential GPS (DGPS)
差分GPS(DGPS)
dilution of precision (DOP)
精度因子(DOP)
characteristic equation
特征方程(式)
chip
码片
chipping rate
码率
chip-scale atomic clocks (CSAC)
片式原子钟(CSAC)
circular error probable (CEP)
园误差概率
boxcar滤波器
Bureau International des Poids et Mesures (BIPM)
国际时间局
Butterworth filter
巴特沃思(Butterworth)滤波器
C
Coarse/Acquisition (C/A)-code
欧洲静地导航重迭系统(EGNOS)
F
feedback
反馈
Fermat’s principle
Trimble4700 RTK操作手册
G HJ\CK\QTSC\RTKSC 22Trimble4700 RTK-DGPS操作手册广州航道局测量勘察分公司一.仪器简介Trimble 4700 (1+2,即1个基准站加两个流动站)是美国天宝公司生产的双频RTK ,目前其平面、高程定位精度达到厘米级,可以进行静态测量、快速静态测量和实时动态测量等(本操作手册主要以实时动态测量为主)。
广泛应用于平面、高程控制测量,施工放样,大比例尺水深测量,无验潮水深测量,以及求取不同坐标的转换参数等方面。
二. 仪器连接1.无线电台前 板 图 后板接口(黄色没电) (闪则有发射) (闪则收到干扰信号) (接GPS 接收机口3) (接无线电发射天线)2. GPS 接收机前板指示灯 后板接口三. 基准站手簿操作(一)手簿界面图文 件 测 量坐标几何 仪 器 注:“键入”项目主要用于点线测量的施工放样;“坐标几何”项目主要用于一些测量计算。
(二) 建立任务1.文件——任务管理——新建直接输入新建任务的名称后回车确认,也可以从旧任务复制任务内容,或删除修改等。
2.选择坐标系统 选键入参数,选项如右图。
基准站点坐标一般是输入WGS-84的B 、L 、H 坐标, 则相关参数设置如下: A . 投影:类型—无投影,坐标—网格 B . 基准转换:类型—无转换 C . 水平平差:类型—无平差 D . 垂直平差:类型—无平差选项:坐标几何设定。
距离—地面,南方位角(网格)—否,网格坐标—东-北方向增加, 磁偏角— 0 , 划分点代码—名称, 缺省高程值—?(三) 检查任务 1.选择任务通过 “文件—任务—管理—选择任务—选取任务对象”,可把所建立的任务选为当前任务。
2.检查任务通过“文件—检查当前的任务”,可分别选取各对象,按右箭头显示详细内容。
(四)配置1.任务A.坐标系统:默认为选定的当前任务格式。
B.单位:角度—DDD.MMSS(度.分秒),坐标显示—WGS-84(网格为54-BJ),坐标顺序—一般选“北-东-高程”的经纬度格式(还有东-北-高程、Y-X-Z、X-Y-Z),距离和网格坐标—米,高程—米,面积—平方米,桩号—1+000.0(10000.0、10+00.0),坡度—百分比,显示激光垂直角度—垂直角度。
GNSS接收机天线相位中心改正对高精度定位影响
GNSS接收机天线相位中心改正对高精度定位影响黄功文;王小瑞;党引群;蒋勇【摘要】阐述了GNSS接收机天线相位中心偏差(PCO)的产生原理及其改正模型,同时重点介绍了现阶段我国天线相位中心测定的基本原理及方法,并分析其优缺点,用算例分析了接收机天线相位中心改正对定位结果的影响,针对 GNSS接收机天线的使用以及我国接收机天线相位中心的检测提出了一些思路和建议。
%This paper first describes the principle of GNSS receiver antenna phase center offset and variation and correction models,then introduces and compares the advantages of bas-ic principles and methods about antenna phase center calibration in china.Finally,a practical example was given to research the influence GNSS antenna phase center corrections on precise positioning,some suggestions are given about the GNSS receiver antenna using and calibration in china.【期刊名称】《全球定位系统》【年(卷),期】2014(000)002【总页数】6页(P49-53,59)【关键词】相位中心偏差;相位中心变化;改正模型;天线检测【作者】黄功文;王小瑞;党引群;蒋勇【作者单位】国家测绘地理信息局大地测量数据处理中心,陕西西安 710054;国家测绘地理信息局大地测量数据处理中心,陕西西安 710054;国家测绘地理信息局大地测量数据处理中心,陕西西安 710054;四川省第三测绘工程院,四川成都610500【正文语种】中文【中图分类】P228.40 引言全球卫星导航系统(GNSS)接收机天线相位中心偏差(PCO)是指天线参考点(ARP)和平均电子相位中心(MPC)的差距。
外文翻译GPS全世界卫星定位系统
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 civilianuse , 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 use only 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 observingstations. 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 coordinate system, 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 effectscan be modeled.(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 standardand 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 phase measurements 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 theseapplications 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全世界卫星定位系统全世界性定位系统(GPS) 是一种革命化勘测技术, 像它的先辈, 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: 几乎所有是操作都能够在各类天气和日夜完成;在野外观测和数据处置中所需要的技术和技术是不同的。
国家授时中心昊平站40 m口径射电天线相位中心参考点坐标的精密测定
国家授时中心昊平站40 m口径射电天线相位中心参考点坐标的精密测定田镇;杨志强;石震;党永超;张喆【摘要】给出国家授时中心昊平站40 m口径射电天线相位中心参考点坐标的测量技术方案,包括GPS控制网布设、观测及解算,天线旋转中心的测定与曲线拟合以及天线旋转中心坐标到参考点坐标的转化等.精度分析表明,所得的天线相位中心参考点在CGCS2000坐标系下的点位精度优于8 mm.【期刊名称】《大地测量与地球动力学》【年(卷),期】2016(036)010【总页数】5页(P897-901)【关键词】射电天线;旋转中心;相位中心参考点;曲线拟合;坐标转换【作者】田镇;杨志强;石震;党永超;张喆【作者单位】长安大学地质工程与测绘学院,西安市雁塔路南段126号,710064;长安大学地质工程与测绘学院,西安市雁塔路南段126号,710064;长安大学地质工程与测绘学院,西安市雁塔路南段126号,710064;国家测绘地理信息局第一地理信息制图院,西安市友谊东路334号,710054;中国科学院国家授时中心,陕西市书院东路3号,710600【正文语种】中文【中图分类】P226中国科学院国家授时中心昊平观测站位于陕西省洛南县保安镇,距离西安市150 km。
40 m口径天线结合信号接收、信号采集和数据存储等设备,共同组成了空间信号质量监测评估系统。
该系统主要用于跟踪和接收GNSS卫星下行信号,实现GNSS卫星信号的高精度观测和分析。
精确的天线相位中心坐标在系统运行及维护过程中非常重要,而求取相位中心的三维坐标,必须首先以较高的精度测定天线相位中心参考点(以下简称参考点)的坐标。
射电天线的参考点位于反射体之上,其空间位置会随着天线方位角和俯仰角的变化而变化[1],难以直接采用大地测量的方法标定其坐标。
但在天线设计之初,参考点与旋转中心的几何关系已经确定,且天线安装之后这一几何关系基本不会发生变化。
因此,可以先测定旋转中心的空间坐标,再通过坐标转换求得参考点坐标。
卫星导航术语200条
28.C/A码(C/A Code):C/A是Coarse /Acquisition或Clear/Acquisition的缩写,C/A码的字 意是容易捕获的码。它调制在GPSL1信号上,是1023个伪随机二进制双相调制序列。其 码速率为1.023MHz,因此码的重复周期为一毫秒。该C/A码用来提供良好的捕获特性。
58. 多普勒辅助(Doppler Aiding):利用观测的多普勒载波相位来平滑码相位的测量值。也称载波辅助平滑或载波辅助跟踪。 59. 多普勒频移(Doppler Shift):所接收到的信号的频移,取决于发射机与接收器间的距离的变化率。见“重建载波相位”二次
差分模糊值解(Double-Difference Ambiguity Resolution)确定一组模糊值的一种方法。该值使在求解两个接收器基线矢量 解时的方差减至最小。 60. 动态定位(Dynamic Positioning):按时间顺序求解运动中的接收器的坐标。每一组坐标只由一次信号取样来确定,且通常进 行实时解算。
56. 差分(相对)定位(Differential(Relative)Positioning):两个(或更多的)同时跟踪相同卫星的进行接收器的相对坐标的测 定。动态差分定位是一种通过一个(或多个)监测站向移动的接收器发送差分修正码而实现实时定位的技术。GPS静态差分 的目的是测定一对接收器之间的基线向量。
29.载波(Carrier):是一个无线电波。能用调制的方法使它至少有一个特怔量(如频率、振 幅、相位)发生改变而偏离它的已知参考值。
30.载波差拍相差(Carrier Beat Phase):当输入的含有多普勒频移的卫星载波信号与接收器 中产生的标称恒定参考频率产生差拍(产生差频信号)所得到的信号相位。
GPS中英翻译
Absolute Positioning 绝对定位Ambiguity 整周模糊度Antenna 天线Antenna-phase-center offset 天线相位中心补偿Baseline Vector 基线向量Broadcast Ephemeris 广播星历Carrier phase measurements 载波相位测量值control networks 控制网coordinate transformation 坐标变换Coordinated Universal Time 协调世界时cutoff angle 截至角cycle slip 周跳differential corrections 差分矫正Differential GPS 差分GPS Differential Positioning差分定位Dilution of Precision 精度因子double-differenced observation 双差观测值Dual-frequency GPS receiver 双频GPS接收机Ephemeris errors 星历误差Ephemeris Errors 星历误差epoch 历元Geodetic Survey 大地测量Geographic Information System地理信息系统Geometric Dilution of Precision 几何精度因子Global Navigation Satellite System 全球导航卫星系统GPS receiver GPS接收机GPS satellite constellation GPS卫星星座GPS signal structure GPS信号结构high precision positioning techniques 高精度定位技术Independent Baseline 独立基线Ionospheric Delay 电离层延迟Kinematic Positioning 动态定位Local Area Differential GPS局域差分GPS longitude,latitude and altitude 经度,纬度与大地高multipath effect 多路径影响Phase-Smoothed Pseudo-Range 相位平滑伪距Precise Ephemeris 精密星历propagation path 传播路径pseudo-range measurement 伪距测量值Real Time Kinematic 实时动态Reference Ellipsoid 参考椭球Relative Positioning 相对定位Satellite and receiver clock error 卫星与接收机钟差simultaneous loop closure 同步闭合环single-differenced observation 单差观测值single-frequency GPS receiver 单频GPS接收机static GPS surveying 静态GPS测量The electron density 电子密度the Geoid surface 大地水平面The Orthometric Height 正高Triple-Difference 三差Tropospheric Delay 对流层延迟Wide Area Differential GPS 广域差分GPS World Geodetic System 1984 WGS-84全球大地坐标系。
GPS词汇
《卫星定位技术与方法》双语教学词汇手册AAFV: Ambiguity Function Value: 模糊度函数AS—anti-spoofing:反电子欺骗技术ATI(International Atomic Time):原子时ambiguity resolution theory--模糊度分解理论all weather:全天候antenna phase center error:天线相位中心偏差almanac:卫星历书数据amplitude: 振幅absolute positioning: 伪距绝对定位approximate value: 近似值astrogeodetic network:天文大地网argument of ascending node: 升交距角argument of perigee:近地点角距astronomical observatory:天文台ascending node:升交点azimuth and elevation:方位角与高度角Bbase station: 基站broadcast ephemeris:广播星历CCDMA—code division multiple access 码分多址CHAMP—challenging mini-satellite payload 挑战小卫星有效荷载CIO—conventional international origin:协定原点CODE—center for orbit determination in Europe 欧洲轨道确定中心CORS—continuously operating reference station 连续运行参考站CRF—celestial reference frame 天球参考架carrier signal:载波信号carrier phase observable:载波相位观测量celestial navigation:天体导航celestial polar and celestial axis:天极与天轴celestial equator:天球赤道celestial rectangle coordinate:天球直角坐标central meridian:中央子午线celestial spheric coordinate: 天球球面坐标chipping rate:码率Covariance: 协方差阵chipping width:码元宽度clock error:钟差cofactor matrix: 协因数阵constellation:星座compass navigation:磁针(罗盘仪)导航choke ring antenna: 扼流圈天线cosine-theorem:余弦定律control segment:监控部分Conventional inertial reference system—CIRS/celestial fixed frame:协议惯性系Conventional terrestrial reference system—CTRS/earth fixed frame:协议地固系coarse/acquisition code:(C/A码)测距粗码conventional celestial spheric coordinate system: 协议天球坐标系cycle slip detecting: 周跳探测DDGPS—differential GPS 差分GPSDLL—delay lock loop 延迟锁定环DMA—defense mapping agency 国防制图社DoD-Department of Defence:美国国防制图局DoT—department of transportation 运输部Data link : 数据链damping factor: 为衰减因子design matrix:设计矩阵Direction cosine: 方向余弦GDOP(Geometric DOP):几何精度因子diffraction:衍射dispersive medium: 散射介质Dilution of Precision—DOP: 精度因子double difference operator: 双差运算符double-differenced measurement: 双差观测量Doppler positioning : 多普勒定位dynamic noise:动态噪声EEGM—earth gravitational model 地球重力场模型EGNOS—European geostationary navigation overlay service 欧洲静地卫星导航服务ERS—earth orientation parameters 地球旋转参数ellipsoid parameters and geodetic origin:椭球参数和大地原点ecliptic plane:黄道eccentric anomaly:偏近点角encrypted P-code:对P码实施加密eccentricity:偏心率error equation :误差方程extra path length :多余路径FFDMA—frequency division multiple access 频分多址FGCC—federal geodetic control committee 联邦大地测量控制委员会FOC—full operational capability 完全运行能力FTP—file transfer protocol 文件传输协议Fast Ambiguity Resolution Approach —FARA: 快速模糊度分解法feedback shift register:反馈移位寄存器float solution:浮点解GGBAS—ground-based augmentation system 地基增强系统GCS-ground control system:地面控制站GEO—geostationary orbit (satellite) 地球静止轨道卫星GIM—global ionosphere map 全球电离层图GLONASS—global navigation satellite system全球导航卫星系统(俄罗斯)GNSS-- global navigation satellite system 全球导航卫星系统GPS—全球定位系统Gauss projection:高斯投影geocentric coordinate:地心坐标geocentric coordinate):地心坐标geomagnetic longitude :地磁经度general relativity:广义相对论geoid undulation:大地水准面差距Greenwich prime meridian:格林尼制子午线Greenwich mean meridian:格林尼治平均子午面group velocity:群速度HHDOP(Horizontal DOP):平面位置精度因子hand-over word—HOW交换码height abnormal:高程异常hyperbolic positioning: 双曲线定位IIAG—international association of geodesy 国际大地测量协会IAT—international atomic time 国际原子时IAU—international astronomical union 国际天文联合会IERS—international earth rotation service 国际地球旋转服务IGS—international GPS service (for geodynamics) 国际GPS服务ILS—instrument landing system 仪表着陆系统INMARSAT—international maritime satellite (organization) 国际海事卫星组织INS—inertial navigation system 惯性导航系统IOC—initial operational capability 初步运行能力ION—institute of navigation 导航学会ITRF—international terrestrial reference frame 国际地面参考架ITS—intelligent transportation system 智能运输系统ITU—international telecommunication union 国际无线通讯协会IUGG—international union for geodesy and geophysics 国际大地测量与地球物理联合会IWV—integrated water vapor 积分水汽IERS—international earth rotation service:国际地球自转服务组织inclination:卫星轨道倾角iron-spheric delay error:电离层延时误差inertial navigation:惯性导航initialization of ambiguity:模糊度初始化ionospheric refraction: 电离层折射Integer Ambiguity:整周模糊度Iono-free Observable:消电离层观测量JJD--Julian date 儒略日JPS—jet propulsion laboratory 喷气推进实验室KKeplerian parameterKalman filter : 卡尔曼滤波法Krasovsky’s ellipsoid:克拉索夫斯基椭球元素LLAAS—local area augmentation system 局域增强LEO—low earth orbit (satellite) 低轨地球卫星LORAN—long-range navigation (system) 长距离导航系统leap second:跳秒Least Squares Adjustment:最小二乘平差Linearized observation equation: 伪距观测方程的线性化longtitude of ascending node:升交点经度Long Range Navigation-LORAN:远程无线电导航系统local-level system or east-north-up 局部水平坐标系local meridian当地子午线MMEDLL—multipath estimating delay lock loop 带多路径估计的延迟锁定环MIT—Massachusetts institute of technology 麻省理工学院MLS—microwave landing system 微波着路系统MT(Mean Time):平太阳时major radius:长半径mean anomaly at reference time:参考时刻的平近点角mean anomaly:平近点角mean angle between ecliptic and equator:平黄赤交角mean polar:平地极mean yellow sea level:黄海平均海水面meridian:子午线multipath:多路径multi-polynomial fitting: 多项式拟合法multipath estimating delay lock loop—MEDLL: 多路径估计性能的锁相环。
天线馈源等效相位中心的确定方法
With the development of communications, radar, satellites and aerospace technology, antenna tracking, positioning accuracy have become increasingly demanding and rely solely on the magnitude of beam search positioning can not meet the requirements of the antenna phase center as a benchmark for accuratepositioning or measuring the performance of reflector antennas and feed characteristics areclosely related. As the diameter of the reflecting surface phase distribution of the radiation characteristics is much larger than the amplitude distribution, the phase center of antenna feed, and find the best location of the feed phase center, so that the antenna feed nearly symmetric radiation characteristics, it is necessary to improve the overall performance of the reflector antenna. Reflecting surface by gravity, wind, ice, snow and other loads role in the actual project, the actual surface will no longer be the ideal surface.
卫星导航测量型天线的相位中心标定
卫星导航测量型天线的相位中心标定董建明;魏亮;易卿武【摘要】测量型天线的相位中心标定是在高精度卫星导航接收机中必不可少的研究工作,在辨析天线相位中心的基础上,分析了产生相位中心偏差的原因,重点研究了天线相位中心的暗室测量方法和室外校准方法,实验证明测量型天线相位中心标定校准之后,在高精度测量的应用中,基线解算后得出的测量精度大大提高,为卫星导航系统高精度测量的工程实践提供了方法指导。
%During the measurement in satellite navigation positioning,the antenna phase center deviation affects the result of navi-gation positioning,which can not be ignored for high-precision measurement.Hence,it is essential for high-precision satellite navigation receiver verification to detect the phase center deviation of surveying antenna.In this paper,antenna phase center is described and its phase center variation is analyzed. Anechoic chamber measurement method and outdoor field measurement method for antenna phase center are analyzed.It has been demonstrated that measurement precision is dramatically improved by this sort of methods,which can provide guidance for engineering practice in terms of high precision satellite navigation system.【期刊名称】《无线电工程》【年(卷),期】2014(000)006【总页数】4页(P47-50)【关键词】相位中心偏移量;相位中心变化量;暗室测量;短基线【作者】董建明;魏亮;易卿武【作者单位】河北省卫星导航技术与装备工程技术研究中心,河北石家庄050081;河北省卫星导航技术与装备工程技术研究中心,河北石家庄050081;河北省卫星导航技术与装备工程技术研究中心,河北石家庄050081【正文语种】中文【中图分类】TN9670 引言在卫星导航高精度测量系统中,观测量都是以天线相位中心为基准得到的,所测量的伪距和载波相位值都是接收机天线的相位中心到卫星的发射天线的相位中心之间的距离[1]。
全球定位系统(GPS)术语及定义
全球定位系统(GPS)术语及定义全球定位系统(GPS)术语及定义【中华人民共和国国家标准GB/T 19391-2003 】2004-12-24 5:55:151范围本标准规定了全球定位系统(GPS)常用术语及定义。
本标准适用于GPS专业范围内的各种标准的制定、各类技术文件的编制,也适用于科研、教学等方面。
2通用术语2.1全球定位系统global positioning system(GPS)导航星navigation by satellite timing and ranging(NA VSTAR)一种卫星导航定位系统。
由空间段、地面控制段和用户段三部分组成.为伞球用户提供实时的三维位置、速度和时间信息。
包括主要为军用的精密定位服务(PPS)和民用的标准定位服务(SPS)。
2.2全球导航卫星系统global navigation satellite system(GLONASS)一种全球卫星导航定位系统:为全球用户提供实时的三维位置、速度和时间信息。
包括军用和民用两种服务。
2.3伽利略系统Galileo system一种民用全球卫星导航系统;2.4全球导航卫星系统global navigation satellite system(GNSS)由国际民航组织提出的概念。
GNSS的最终目标是由多种民用卫星导航系统组成,向全球民间提供服务。
并将由多国民间参与运行和控制的卫星导航系统。
GNSS也已经为国际海事组织(IMO)所接受。
欧洲的GNSS计划分为两个阶段,即GNSS-1和GNSS-2。
GNSS-1为EGNOS(欧洲地球静止轨道卫星导航重叠服务)系统,GNSS-2为Galileo(伽利略)系统。
2.5静地星/定位星系统Geostar/Locstar system一种卫星定位系统,利用两颗地球轨道静止卫星双程测距而实现定位功能,兼有简短报文通信能力。
2.6海军导航卫星系统navy navigation satellite system(NNSS)子午仪Transit是1960年由美国研制的卫星导航系统,为固定用户或低动态用户提供不连续定位信息。
GPS词汇
《卫星定位技术与方法》双语教学词汇手册AAFV: Ambiguity Function Value: 模糊度函数AS—anti-spoofing:反电子欺骗技术ATI(International Atomic Time):原子时ambiguity resolution theory--模糊度分解理论all weather:全天候antenna phase center error:天线相位中心偏差almanac:卫星历书数据amplitude: 振幅absolute positioning: 伪距绝对定位approximate value: 近似值astrogeodetic network:天文大地网argument of ascending node: 升交距角argument of perigee:近地点角距astronomical observatory:天文台ascending node:升交点azimuth and elevation:方位角与高度角Bbase station: 基站broadcast ephemeris:广播星历CCDMA—code division multiple access 码分多址CHAMP—challenging mini-satellite payload 挑战小卫星有效荷载CIO—conventional international origin:协定原点CODE—center for orbit determination in Europe 欧洲轨道确定中心CORS—continuously operating reference station 连续运行参考站CRF—celestial reference frame 天球参考架carrier signal:载波信号carrier phase observable:载波相位观测量celestial navigation:天体导航celestial polar and celestial axis:天极与天轴celestial equator:天球赤道celestial rectangle coordinate:天球直角坐标central meridian:中央子午线celestial spheric coordinate: 天球球面坐标chipping rate:码率Covariance: 协方差阵chipping width:码元宽度clock error:钟差cofactor matrix: 协因数阵constellation:星座compass navigation:磁针(罗盘仪)导航choke ring antenna: 扼流圈天线cosine-theorem:余弦定律control segment:监控部分Conventional inertial reference system—CIRS/celestial fixed frame:协议惯性系Conventional terrestrial reference system—CTRS/earth fixed frame:协议地固系coarse/acquisition code:(C/A码)测距粗码conventional celestial spheric coordinate system: 协议天球坐标系cycle slip detecting: 周跳探测DDGPS—differential GPS 差分GPSDLL—delay lock loop 延迟锁定环DMA—defense mapping agency 国防制图社DoD-Department of Defence:美国国防制图局DoT—department of transportation 运输部Data link : 数据链damping factor: 为衰减因子design matrix:设计矩阵Direction cosine: 方向余弦GDOP(Geometric DOP):几何精度因子diffraction:衍射dispersive medium: 散射介质Dilution of Precision—DOP: 精度因子double difference operator: 双差运算符double-differenced measurement: 双差观测量Doppler positioning : 多普勒定位dynamic noise:动态噪声EEGM—earth gravitational model 地球重力场模型EGNOS—European geostationary navigation overlay service 欧洲静地卫星导航服务ERS—earth orientation parameters 地球旋转参数ellipsoid parameters and geodetic origin:椭球参数和大地原点ecliptic plane:黄道eccentric anomaly:偏近点角encrypted P-code:对P码实施加密eccentricity:偏心率error equation :误差方程extra path length :多余路径FFDMA—frequency division multiple access 频分多址FGCC—federal geodetic control committee 联邦大地测量控制委员会FOC—full operational capability 完全运行能力FTP—file transfer protocol 文件传输协议Fast Ambiguity Resolution Approach —FARA: 快速模糊度分解法feedback shift register:反馈移位寄存器float solution:浮点解GGBAS—ground-based augmentation system 地基增强系统GCS-ground control system:地面控制站GEO—geostationary orbit (satellite) 地球静止轨道卫星GIM—global ionosphere map 全球电离层图GLONASS—global navigation satellite system全球导航卫星系统(俄罗斯)GNSS-- global navigation satellite system 全球导航卫星系统GPS—全球定位系统Gauss projection:高斯投影geocentric coordinate:地心坐标geocentric coordinate):地心坐标geomagnetic longitude :地磁经度general relativity:广义相对论geoid undulation:大地水准面差距Greenwich prime meridian:格林尼制子午线Greenwich mean meridian:格林尼治平均子午面group velocity:群速度HHDOP(Horizontal DOP):平面位置精度因子hand-over word—HOW交换码height abnormal:高程异常hyperbolic positioning: 双曲线定位IIAG—international association of geodesy 国际大地测量协会IAT—international atomic time 国际原子时IAU—international astronomical union 国际天文联合会IERS—international earth rotation service 国际地球旋转服务IGS—international GPS service (for geodynamics) 国际GPS服务ILS—instrument landing system 仪表着陆系统INMARSAT—international maritime satellite (organization) 国际海事卫星组织INS—inertial navigation system 惯性导航系统IOC—initial operational capability 初步运行能力ION—institute of navigation 导航学会ITRF—international terrestrial reference frame 国际地面参考架ITS—intelligent transportation system 智能运输系统ITU—international telecommunication union 国际无线通讯协会IUGG—international union for geodesy and geophysics 国际大地测量与地球物理联合会IWV—integrated water vapor 积分水汽IERS—international earth rotation service:国际地球自转服务组织inclination:卫星轨道倾角iron-spheric delay error:电离层延时误差inertial navigation:惯性导航initialization of ambiguity:模糊度初始化ionospheric refraction: 电离层折射Integer Ambiguity:整周模糊度Iono-free Observable:消电离层观测量JJD--Julian date 儒略日JPS—jet propulsion laboratory 喷气推进实验室KKeplerian parameterKalman filter : 卡尔曼滤波法Krasovsky’s ellipsoid:克拉索夫斯基椭球元素LLAAS—local area augmentation system 局域增强LEO—low earth orbit (satellite) 低轨地球卫星LORAN—long-range navigation (system) 长距离导航系统leap second:跳秒Least Squares Adjustment:最小二乘平差Linearized observation equation: 伪距观测方程的线性化longtitude of ascending node:升交点经度Long Range Navigation-LORAN:远程无线电导航系统local-level system or east-north-up 局部水平坐标系local meridian当地子午线MMEDLL—multipath estimating delay lock loop 带多路径估计的延迟锁定环MIT—Massachusetts institute of technology 麻省理工学院MLS—microwave landing system 微波着路系统MT(Mean Time):平太阳时major radius:长半径mean anomaly at reference time:参考时刻的平近点角mean anomaly:平近点角mean angle between ecliptic and equator:平黄赤交角mean polar:平地极mean yellow sea level:黄海平均海水面meridian:子午线multipath:多路径multi-polynomial fitting: 多项式拟合法multipath estimating delay lock loop—MEDLL: 多路径估计性能的锁相环。
GPS天线相位中心变化及测试
GPS天线相位中心变化及测试
翟清斌;齐维君
【期刊名称】《测绘科学》
【年(卷),期】2004(29)2
【摘要】对GPS天线相位中心随卫星变化的情况及减小和消除天线相位中心误差的方法进行了阐述。
【总页数】4页(P60-63)
【关键词】天线相位中心变化;Antenna;Phase;Center;Variation
【作者】翟清斌;齐维君
【作者单位】中国测绘科学研究院国家光电测距仪检测中心
【正文语种】中文
【中图分类】P208
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Influence of GPS antenna phase center variation on precise positioningAhmed I.EL-Hattab*Port Said University,Faculty of Engineering,EgyptReceived20October2013;revised10November2013;accepted13November2013Available online28November2013KEYWORDS Antenna calibration; Phase center variation; Precise positioning; Mixed antenna Abstract The GPS antenna is the connecting element between the GPS satellites and the GPS receiver.It receives the incoming satellite signal and then converts its energy into an electric current, which can be managed by the GPS receiver.The accurate antenna phase center offsets’values and phase center variation factors are critical issues in GPS precise positioning.Some GPS users simply apply the manufacturer’s recommended offset values which may not match the precise values deter-mined by calibration process.Other users may ignore the phase center correction factors during GPS data processing.In both cases,the resulted coordinates will have errors especially the height component.In this study,some static and kinematicfield experiments have been carried out to evaluate the effect of using the manufacturer’s recommended antenna phase offset and ignoring its variation on precise positioning.The GPS data have been post-processed by two commercial software.The results showed that,a significant error may occur in case of disregarding the calibrated values and applying the manufacturer’s recommended ones.Investigation is also made on the effects of mixing different types of antennas.Significant variations are observed on the height components than the associated horizontal component due to phase center variation.The maximum variations are reached about8and4cm in height and northing components respectively.ª2013Production and hosting by Elsevier B.V.on behalf of National Research Institute of Astronomyand Geophysics.1.IntroductionThe GPS antenna is the connecting module between the GPSsatellite and the GPS receiver.It is used tofilter,amplify,and convert the incoming signal from satellites into an electri-cal signal that can be processed by the receiver.The point atwhich the GPS signal is received is called antenna phase center(APC).APC does not coincide with the antenna physical(geo-metrical)center and varies with elevation,azimuth,intensity ofthe satellite,and frequency of the incoming signal.Therefore,amean position of the electrical antenna phase center is deter-mined for the purpose of the offset calibration.*Tel.:+201060147785.E-mail address:dr.ahmed.elhattab@Peer review under responsibility of National Research Institute of2090-9977ª2013Production and hosting by Elsevier B.V.on behalf of National Research Institute of Astronomy and Geophysics. /10.1016/j.nrjag.2013.11.002A relative GPS carrier phase solution effectively measures the vector between the phase centers of two antennas situated at either end of a baseline.To relate this vector to physical points on the ground,the exact location of the phase center of each antenna relative to those points must be known.Stan-dard GPS processing procedures reduce all GPS observations APC to the station reference point by way of the measured ver-tical antenna height.This height is usually measured by the user to some point on the antenna specified by the receiver manufacturer called antenna reference point (ARP).The con-stant vector between APCand ARP is called phase center off-set (PCO).It should be provided by the manufacturer;if not,the determination of these coordinates is carried out by a cal-ibration procedure (Go rres et al.,2006).The main phase center offset component is vertical but there are also small horizontal offsets.There are two-phase centers,one for the L1frequency and the other for L2,but each phase center has a different off-set as introduced in Fig.1.Antenna phase center variation (PCV)is a deviation of the antenna phase center beyond the antenna offset.The GPS 2.Determination of antenna phase center variationsCombining GPS with other space-geodetic techniques becomes difficult in case of unmodeled systematic errors due to impro-per GPS antenna calibration models.As a consequence scale differences have been seen in GPS reference frames.Nowa-days,relative PCV calibration models are commonly used as the standard GPS processing method,but there is no guaran-tee that they are applicable for different circumstances.Three Fig.1Main points of a model GPS antenna.Fig.2Absolute antenna calibration methods (Bilich et al.,2012).The drawback is that the corrections are dependent on the zero/reference antenna and that PCVs at low elevations are not reliable due to the increase of noise and multipath in mea-surements below10°(Mader,2002).National geodetic survey (NGS)is one of the organizations that provides complete sum-mary of all calibration results free of charge.The main idea of the laboratory antenna calibration proce-dure is to simulate the different signal directions by rotations of the antenna.Therefore,the calibration setup consists of a fixed transmitter on the one end and a remote-controlled posi-tioner carrying the test antenna on the other end of the test range.At every selected antenna position(equal to a satellite direction)a network analyzer generates a signal which is trans-mitted in the direction of the GNSS antenna.The antenna is also connected equipment that the network analyzer can mea-sure the phase shift between the outgoing and incoming sig-nals.This phase delay depends on the signal direction.Since the outgoing signal is constant,a grid of phase corrections is directly obtained as a result of the calibration(Zeimetz and Kuhlmann,2011).In case of calibration the multipath effects can be reduced to a low level by using special anechoic cham-bers as in Fig.2a.The advantage of the laboratory procedure is achieving constant environments forand its very high efficiency.The maintest signal differs from the real GNSSAbsolutefield calibrations are performedcision robot and two antennas.The robotantenna while the reference antenna istages of the absolutefield calibrationsignals are tracked with a real receiverthe naturalfield environment.In contrastna calibrations,the robot measurementstion of patterns to0°elevation andmultipath effects to a large extent asis because the time difference betweenamounts to just a few seconds.Thereforemultipath error in consecutive epochs is highly correlated and can be well described as a stochastic process within a Kal-manfilter(Wu bbena et al.,2006).3.GPS observation modelFor short base lines the double-difference observation model between stations a,b and satellites i,j can be written for L1 or L2frequency as:k/i;ja;b¼q i;ja;bþk N i;ja;bÀD i;ja;bIonþD i;ja;bTropþD i;ja;bMPþD i;ja;bPCOþD i;ja;bPCVþewhere/i;ja;b,phase measurements in cycles;q i;ja;b,range betweenthe receivers at station;N i;ja;b,unknown integer ambiguity;D i;ja;bIon,ionospheric delay in range unites;D i;ja;bTrop,tropo-spheric delay in range unites;D i;ja;bMP,multipath effect;D i;ja;bPCO,antenna phase center offset residuals;D i;ja;bPCV,an-tenna phase center variation;k,signal wave length;e,noise of the phase measurements and unmodelled errors.When the antennas at opposite ends of relatively short baselines are identical,PCV will be canceled out and no effectFig.3First experiment arrangements.Fig.4Bottom of R8-model3antenna.Table1Results of G1-T baseline.Point Easting(m)Northing(m)Height(m)RemarksG1469306.5033505726.892845.000ReferenceT469306.8943505727.282845.021Manufacturer’s PCOT469306.8953505727.281845.002NGS calibration factors T469306.8953505727.281844.998Without PCV factorsis remained.However,different antenna types exhibit different PCV and baselines with different antenna types will show increasing sensitivity to such things as elevation cutoff angle and the distribution of observations within a solution (Mader,2002).Antenna PCO residuals should also be canceled out if the same antenna type is ing mixed types,some effects may remain which have influence on the calculated coordi-nates.In case of long baselines,PCV at the opposite ends will not be canceled out since the satellite zenith angles will be dif-ferent and accordingly the PCV.4.Field experiment procedures and resultsTo evaluate the effect of antenna phase center offset and its variation on the baseline solution,three field experiments have been performed.In the first experiment three GPS antennas have been used;two Leica GS15,and one Trimble R8-Model 3.Trimble and one of the Leica antennas have been fixed over a leveled flat table as shown in Fig.3.The two stations were named T and G1respectively and hence the ARP of the two antennas has the same height value.The other Leica antenna named G2was fixed over tripod 70m away from the table.Two hours of GPS data were collected with 10s sampling interval and 15°cut-off angle.Fig.4shows the bottom of trimble antenna where the man-ufacturer’s recommended L1PCO is printed with a value of 6.49cm.To evaluate the recommended PCO,the baselineG1-T was processed using Leica Geo Office (LGO)Ver.7.The station G1was considered as a reference and T as a rover.The processing was performed to solve the baseline using the manufacturer’s recommended PCO value,using calibrated PCO and PCV factors,and without applying PCV factors.The resulted coordinates of the rover station T are listed in Table 1.One can notice that the rover’s height component has 0.02m difference in case of using the manufacturer’s recom-mended PCO for Trimble antenna.Only 0.002m height difference in case of NGS calibrated PCO and PCV.In case of ignoring PCV the height difference becomes À0.002m.Since ARP of both antennas has the same level,it is expected that the resulted height components will have the same value for the reference and rover stations.It is obvious that,NGS calibration is more accurate than the manufacturer’s recom-mended value while ignoring PCV has no significant effect since the baseline is too short.The same results are obtained in case of using Trimble business center (TBC)software ver.2.7.To evaluate the effect of combining different types of anten-nas in one session,the baselines G2-G1and G2-T were pro-cessed.Station G2was considered as reference and the other stations as rovers.Table 2shows the results of the processed baselines using LGO and TBC software.Almost no variations in the horizontal components are ob-served in all ing LGO software,the height componentTable 3Results from processing baseline GMN-TMP.Case No.Easting (m)Northing (m)Height Remarks1496310.1003507967.535888.096Leica +TBC with PCV 496310.1043507967.546888.115Leica +TBC with PCV 496310.1033507967.529888.071Trimble +TBC with PCV 2496310.1063507967.533888.092Leica +LGO with PCV 496310.1103507967.548888.109Leica +LGO with PCV 496310.1163507967.502888.144Trimble +LGO with PCV 3496310.1023507967.529888.093Leica +TBC without PCV 496310.1043507967.546888.115Leica +TBC without PCV 496310.1163507967.502888.144Trimble +TBC without PCV 4496310.1073507967.533888.091Leica +LGO without PCV 496310.1103507967.548888.109Leica +LGO without PCV 496310.1163507967.494888.168Trimble +LGO without PCVTable 2Results of G2-G1and G1-T baselines.Point Easting (m)Northing (m)Height Remarks G2469254.8023505680.527844.292Reference pointG1469306.5033505726.892845.000LGO softwareT 469306.8953505727.279845.003PCV corrections are applied G1469306.5033505726.892845.000LGO softwareT 469306.8953505727.279845.003PCV corrections are not applied G1469306.5033505726.893844.996TBC softwareT 469306.8963505727.279845.020PCV corrections are applied G1469306.5033505726.893844.996TBC softwareT469306.8963505727.279845.027PCV corrections are not appliedInfluence of GPS antenna phase center variation on precise positioning 275of rover station G1is correct by applying PCO and PCV cor-rection factors.While ignoring PCV produces no significant height ing TBC for baseline processing,station G1hasÀ0.004m height difference in case of applying PCO regardless of implements of PCV correction factors.Using mixed types of antenna as in case of rover station T, the changes in height component increase.It is0.003m in case of applying PCO and PCV correction factors and LGO soft-ware while it reaches0.02m when using TBC software.Ignor-ing PCV produces0.006and0.027m height differences in case of using LGO and TBC software respectively.Practically,the baselines during GPS surveying are longer than those in the previous experiment.Therefore,the GPS data of longer baseline GMN-TMP were used for further investigation.The baseline length is about27.3km and the same antennas in the previous experiment have been used. The experiment has been carried out on day numbers129, 131,and174of year2013for about3h observation time perIt is obvious that in case of using Leica receivers on both ends of the baseline;the coordinates are close in all cases. The maximum difference is always in height component then northing and the least is in easting.When using TBC software without applying PCV correction factors,the maximum differ-ences in height and northing components are0.022and 0.017m respectively.In all cases,changes in easting compo-nent are small and in the range of0.002–0.004m.Using mixed types of antenna causes increasing of the coor-dinate differences where the maximum differences in height and northing components are reached at0.077and0.039m respectively when LGO software is used for processing without applying PCV correction factors.By comparing the coordinates,regardless using PCV cor-rections,it is noticed that there is no significant change when the same type of antenna was used.In case of using mixed types of antenna,the difference in height component increased from0.024to0.073m when using LGO,and TGOFig.5Changes of coordinates of station TMP.Fig.6Coordinate difference due to ignoring PCV.276 A.I.EL-Hattabrepeated to compute the coordinates ignoring the PV correc-tions.The difference between the corresponding coordinates has been computed and plotted in Fig.6It is obvious from thefigure that PCV has greater impact on height component than the horizontal components in static positioning.The differences in height range from0.01to 0.03m while they range from0.002to0.004m and from 0.001to0.005m in easting and northing respectively.The continuous variations of difference in the coordinates are due to PCV changes with elevation,azimuth,and number of tracked satellites.The broken lines infigure are due to the changes in the number of the tracked satellites.5.ConclusionThe influence of antenna phase center offset and its variation have been evaluated using GPS data from some static and kinematicfield experiments.The effect of using the manufac-turer’s recommended antenna phase offset and ignoring the phase center variation has been investigated using two differ-ent GPS post-processing commercial software.The following outcomes have been confirmed:1.Applying the manufacturer’s recommended offset valueswhich may differ from the accurate calibrated values will lead to height error equal to the difference between the two values.ing identical antennas at both ends of baselines,thephase center variations may cancel out,particularly over short baselines.3.Even on short baselines,using mixed antennae ignoringphase center variations can lead to serious errors(about 8cm as in this study)in height component.In this case, the only way to avoid these errors is by applying the accu-rate antenna phase center variation factors in processing.4.Each GPS post-processing software has a different proce-dure to manage the antenna phase center variations.5.Antenna phase center variation affects the vertical and hor-izontal components,but its effect on the vertical is greater than the horizontal components in case of static and kine-matic GPS positioning.ReferencesBilich,A.,Schmitz,M.,Go rres,B.,Zeimetz,P.,Mader,G.,Wu bbena,G.,2012.Three-Method Absolute Antenna Calibration Compar-ison.IGS Workshop2012.University of Warmia and Mazury (UWM),Olsztyn,Poland,July23–27.Go rres,B.,Campbell,J.,Becker,M.,Siemes,M.,2006.Absolute calibration of GPS antennas:laboratory results and comparison withfield tests and robot techniques.GPS Solut.10(2),136–145. Hofmann-Wellenhof,B.,Lichtenegger,H.,Wasle,E.,2008.GNSS–Global Navigation Satellite Systems.Springer-Verlag Wien, Austria.Mader,G.,2002.GPS Antenna Calibration at the National Geodetic Survey.National Geodetic Survey,NOS,NOAA,Silver Spring, MD.Schupler,B.R.,Allshouse,R.L.,Clark,T.A.,1994.Signal character-istics of GPS user antennas,navigation.J.Inst.Navig.41(3),277–295.Rothacher,M.,parison of absolute and relative antenna phase center variations.GPS Solut.4(4),55–60.Wu bbena,G.,Schmitz,M.,Boettcher,G.,2006.Separation of Near-Field and Far-Field Multipath:New Strategies for Station Calibration.10th EUPOSÒICS,Budapest,Hungary,November 23–24.Zeimetz,P.H.,Kuhlmann,H.,2011.Validation of the Laboratory Calibration of Geodetic Antennas based on GPS Measurements.FIG Article of the Month,February,2011.Influence of GPS antenna phase center variation on precise positioning277。