略论海洋测高卫星GPS厘米级定轨的实施基础

基于对多种飞机的机载GPS测量实践,认为我国HY-2海洋二号卫星实现厘米级精度的星载GPS定轨测量的基础是:选择适合天线,捕获多颗在视GPS卫星;注重天线安装位置,减弱多路径效应影响;选择适合GPS信号接收机,确保星载GPS测量数据优质。     

靶场测量装备中GPS换装北斗卫星导航系统方案设计

目前,根据装备试验要求,利用北斗卫星导航系统全面替换靶场测量装备中所使用的GPS已成为必须开展的工作。如果直接替换,则现有测量系统需重新进行测试,代价较高。为此,结合靶场测量装备实际情况,设计一种基于北斗卫星导航系统,集定位、测姿、授时为一体的便携式信息采集分发系统,系统具备多种对外数据传输接口,无需对现有装备进行较大改造,即可全面实现北斗取代GPS的目的。     

GPS卫星星历计算的研究

针对目前存在的两种GPS卫星星历,分别给出了计算卫星星历的方法,并结合实际观测数据进行了比较,给出了比较结果,得出了星历精度的有益结论。     

GPS／GLONASS信号的同机接收问题

本文综述了GPS/GLONASS卫星及其导航定位信号的异同点,讨论了GPS/GLONASS集成接收机的研制难点。     

GPS输出的NMEA 0183信号的时间特性分析

为判断GPS接收机输出的NMEA0183信号是否可作为水下地形测量的同步信号，对多种CPS接收机输出的NMEA0183信号的时间特性进行了测试与分析。     

基于随机共振的GPS接收信号消噪方法

GPS接收信号中的噪声干扰一直以来都是研究人员想方设法消除的不利因素,但在某些非线性系统中,噪声的存在却能够提高信号的检测性能,利用Langevin方程构建的非线性随机共振系统对GPS接收信号进行消噪处理,经过对仿真信号的验证,消噪效果明显,将在GPS接收信号消噪领域得到很好的应用。     

利用GPS导航信号进行水下地形测量的时间同步

介绍了应用GPS接收机输出的导航信号用于水下地形测量时间同步的原理，并分别讨论了用于模拟测深仪、数字化／模拟测深仪和数字测深仪的同步方法。     

GPS、Galileo、BDS、QZSS测距信号数据质量分析

基于多测站观测数据,采用伪距相位差组合和伪距多径组合方法,分析了GPS、Galileo、BDS和QZSS 4个系统伪距测量噪声和多径误差,比较了各系统内部信号数据质量以及系统间兼容信号数据质量。结果表明:GPS系统中L2C信号伪距测量精度要优于L2信号;Galileo系统中E5信号伪距测量精度最优,其E1和E5a信号伪距测量精度分别优于GPS/QZSS L1和L5信号;QZSS信号伪距测量精度与GPS信号基本一致;BDS系统三频信号伪距多径中均存在与高度角相关的系统性偏差,最大可达1m,且其三类卫星伪距测量精度有所差异,相同高度角条件下,GEO卫星伪距测量精度最优,IGSO卫星次之,MEO卫星最差。     

局域差分GPS改正数学模型分析与比较

局域差分中,用户到基准站的距离对定位精度有着决定性影响。利用基准站生成用户误差改正数,其算法很多,介绍了几种常用的方法,并分析了各方法的内插系数和内插质量因子。利用局域差分GPS进行定位时,只有当流动站位于基准站构成的多边形网内时,才可能得到较高的精度。     

基于GPS反射信号技术的渤海海冰实验

传统的海冰检测手段都存在着受天气影响或实时检测成本太高的缺点,为了更实时有效的检测海冰,减轻海冰灾害对于我国的影响,并达到防灾减灾的目的,本文研究了GPS反射信号(GPS-R)技术检测海冰的可能性。通过对2013年2月下旬在中国天津渤海湾的岸基架设GPS信号接收机所接收的观测数据进行分析,使用不同特性的反射海域(几乎全为海水或是海冰)的数据进行比对分析,其结果显示极化比值(反射左旋信号与直射右旋信号的比值)能够明显反演海冰密集度。本文首次将GPS-R技术应用于国内自主设计的渤海海冰检测实验中。     

基于GPS的水下导航算法误差仿真研究

首先介绍了水下导航算法,采用GPS和水下参量测算相结合的方案,即当运行器在水下运行时,利用电子罗盘测量运行器的相对航向,水流传感器测算运行器的相对速度大小,利用学习阶段计算出海水流速,在水下运行器潜行时进行船位推算导航,用GPS精准的定位信号进行导航误差的校正。此算法精度的高低很大程度上取决于用来进行水下参量测算的传感器和用来方位校准的GPS。文中从各个传感器的误差着手,通过模拟仿真详细分析了电子罗盘、水流传感器和GPS的误差对导航精度的影响,对工程应用具有实际的指导意义。     

GPS实时动态测量在故县水库水下地形测量中的应用

通过水库区域的水下地形测量实践，分析了GPS实时动态测量(RTK)的基准站、流动站设置与定位工作程序对测点精度的影响，实际作业检核表明，利用RTK技术可有效提高水域测量效率和质量。     

观测卫星选择对GPS基线解算质量的影响

研究了观测卫星的选择对基线解算质量的影响，介绍了提高基线解算质量的人工选星的基线处理方法，通过人工干预选择卫星，解算结果得到明显改善。     

GPS测速精度分析与应用

全球定位系统(GPS)技术的出现,为速度测量提供了新的手段。基于GPS测速的基本原理,采用单点定位模式、无线电信标/差分GPS模式和GPS RTK模式,研究了不同模式下速度测量的方法和精度概况,重点分析了GPS RTK模式下的测速精度,并对高精度速度测量应用提出了建议。     

The Effects of GPS Carrier Phase Ambiguity Resolution on Jason-1

We have used GPS carrier phase integer ambiguity resolution to investigate improvements in the orbit determination for the Jason-1 satellite altimeter mission. The technique has been implemented in the GIPSY orbit determination software developed by JPL. The radial accuracy of the Jason-1 orbits is already near 1 cm, and thus it is difficult to detect the improvements gained when the carrier phase ambiguities are resolved. Nevertheless, each of the metrics we use to evaluate the orbit accuracy (orbit overlaps, orbit comparisons, satellite laser ranging residuals, altimeter crossover residuals, orbit centering) show modest improvement when the ambiguities are resolved. We conservatively estimate the improvement in the radial orbit accuracy is at the 10–20% level.     

建立我国沿海永久GPS陆海垂直运动监测网的建议

论述了在我国沿海建立永久GPS陆海垂直运动监测风的目的和意义，介绍了有关的国内外发展现状，监测的方法和原理，最后提出了在我国建立永久GPS陆海垂直运动监测网的具体建议。     

Fast BDS Positioning Convergence Based on the Contribution of GPS Observations

Comparing to single BeiDou Navigation Satellite System (BDS) Precise Point Positioning (PPP), a method which can more quicklydetermine the ambiguity parameters of BDS through applying the contribution of GPS observations is proposed and analyzed in this article. The numerical examples and analysis show that the ionosphere-free ambiguities of BDS satellites can be determined and converged more quickly because of the contribution of GPS observations. The average improvement of the convergent speed of positioning is 18.5% and its positioning accuracy in N, E, and U components are improved by 29.4, 30.3, and 34.4%, respectively, with the contribution of the a priori coordinates obtained from GPS observations. This method is useful for single BDS system positioning when there is a priori information provided by GPS or other sensors which be replaced by and can be applied at the beginning of the computation.     

Accurate GPS measurement of the location and orientation of a floating platform

Abstract

This article describes the design and initial tests of the GPS portion of a system for making seafloor geodesy measurements. In the planned system, GPS antennas on a floating platform will be used to measure the location of an acoustic transducer, attached below the platform, which interrogates an array of transponders on the seafloor. Since the GPS antennas are necessarily some distance above the transducer, a short‐baseline GPS interferometer consisting of three antennas is used to measure the platform's orientation.

A preliminary test of several crucial elements of the system was performed at the Scripps Institution of Oceanography (SIO) in December 1989. The test involved a fixed antenna on the pier and a second antenna floating on a buoy about 80 m away. GPS measurements of the vertical component of this baseline, analyzed independently by two groups using different software, agree with each other and with an independent measurement within a centimeter.

The first test of an integrated GPS/acoustic system took place in the Santa Cruz Basin off the coast of southern California in May 1990. In this test a much larger buoy, designed and built at SIO, was equipped with three GPS antennas and an acoustic transducer that interrogated a transponder on the ocean floor. Preliminary analysis indicates that the horizontal position of the transponder can be determined with a precision of about a centimeter. Further analysis will be required to investigate the magnitude of systematic errors.