星载加速度计增强北斗自主定轨性能     

乔晶  陈武 《测绘学报》2016,45(Z2):116-131

卫星自主定轨是提高全球卫星导航系统(GNSS)可靠性、稳健性、完整性和生存能力的重要保证。新一代的北斗卫星已可以进行星间链路测距,从而达到提高卫星全球跟踪能力以及实现整个卫星导航系统的自主定轨。然而由于卫星运行会受到多种摄动力的影响,如果不能对这些摄动力进行精密的改正,在没有地面或其他天体提供绝对约束的条件下,导航系统会随着自主定轨时间的延长出现星座整体旋转。卫星所受摄动力分为保守力和非保守力两部分:对于保守力,如地球非球形摄动、潮汐摄动、太阳月球和其他三体引力,现在已有的力学模型可以很精确地进行改正;而非保守力(如太阳光压摄动),则难以用精确的模型进行改正,因此成为影响卫星定轨精度的主要因素。星载加速度计可以高精度地测量非保守力,并已成功应用于重力卫星(CHAMP、GRACE、GOCE)的重力场反演与大气研究中。本文研究主要探讨采用星上加速度计提高北斗卫星自主定轨精度和延长自主定轨时长的可行性。利用模拟的卫星轨道和星间链路数据,以及现有的星载加速度计误差模型,对北斗卫星系统分别使用星间链路数据和星间链路与加速度计组合数据,进行自主定轨与精度评定。计算结果表明,使用星间链路与星载加速度计数据进行自主定轨,较单纯使用星间链路数据精度具有明显改进。在模拟的星间测距观测数据具有0.33m随机噪声以及分米级系统误差,自主定轨两个月的情况下,联合使用加速度计数据的自主定轨IGSO和MEO卫星精度为分米级,而仅使用星间链路数据的定轨精度约为3~6m,比使用加速度计精度低一个量级。  相似文献   

Study mobile underwater positioning system with expendable and multi-functional bathythermographs     

Wen-Hui Cheng   《Ocean Engineering》2005,32(3-4):499-512

The purpose of the current study is to introduce a set of mobile underwater positioning systems (MUPS) that will enable non-offshore vessels to execute underwater missions. Besides mobility, the system would also possess the advantage of having to use fewer acoustic instruments than conventional acoustic positioning systems. The method adopted by the system will involve the use of expendable and multi-functional bathythermographs (XBT) to measure the underwater acoustic speed and the depth of water at the same time. Then it must utilize the geometric relations formed by measuring the position of underwater targets at set intervals during navigation. In addition, since sound does not travel in a straight line when underwater, the iteration and convergence method must be used to perform corrections on the transmission speed and positional errors to obtain an accurate coordinate of the underwater target. After simulation testing, the positioning system established by the current study has proven to be fast in converging the error values along with high positioning accuracy of the system. The results of the study indicate that the MUPS built by the research institute can be utilized on a vessel, and will be very helpful in assisting the management of urgent underwater positioning missions.  相似文献   

Low-complexity online correction and calibration of pedestrian dead reckoning using map matching and GPS     

Fabian Hölzke  Johann-P. Wolff  Frank Golatowski  Christian Haubelt 《地球空间信息科学学报》2019,22(2):114-127

  相似文献   

北斗卫星导航系统单星授时精度分析   总被引：2，自引：1，他引：1  

张大众  郑作亚  刘一  谷守周  秘金钟  李杰  张涛 《测绘通报》2019,(4):7-10

为研究北斗卫星导航系统单星授时精度，本文基于GPS单星授时原理，结合北斗卫星多种类型星座特点，编写了BDS单星授时软件。利用iGMAS站数据进行了试验，在对原始数据进行监测并将异常信息剔除后，将授时结果与中国测绘科学研究院北斗分析中心（CGS）钟差文件进行比对，分析了BDS不同轨道卫星（GEO/IGSO/MEO）下的BDS单星授时精度。结果表明，GEO卫星的授时精度为27.39 ns，IGSO卫星的授时精度为18.37 ns，MEO卫星的授时精度为18.62 ns。  相似文献   

GPS/BDS组合实时动态精密单点定位     

杨行言  高雅萍  杨立财  阿苦建英 《北京测绘》2020,(3):417-421

针对常规模式下。单系统实时精密单点定位精度受接收机环境和可视卫星数量影响严重等问题,研究了GPS/BDS双系统实时精密单点定位,采用非差无电离层组合载波和伪距观测值,详细推论了Kalman滤波参数估计方法的基本原理,并利用其进行参数估计,最后通过IGS站和实测数据进行了实时PPP实验,实验表明:GPS/BDS双系统定位模式较GPS单系统有明显改善,在E、N、U方向收敛后RMS值分别达到0.125 m、0.117 m、0.289 m,较单系统在各方向分别改善了11.9%、18.1%、22.5%。证明了GPS/BDS实时PPP能够达到分米级到厘米级定位精度。  相似文献   

A data archive of GPS navigation messages   总被引：2，自引：1，他引：1  

G. Beyerle  M. Ramatschi  R. Galas  T. Schmidt  J. Wickert  M. Rothacher 《GPS Solutions》2009,13(1):35-41

Since 18 June 2007 navigation data messages transmitted by the GPS constellation are recorded by five receivers within GeoForschungsZentrum’s global groundstation network. We describe the recording, processing, validation, analysis and archiving of the navigation data. During the 197 days between 18 June 2007 and 31 December 2007 a total of 125,723,666 subframes were collected. By taking into consideration that the same data set frequently is observed by two or more receivers concurrently, 65,153,955 unique subframes could be extracted from the observations. With an estimated 88,099,200 subframes transmitted by the constellation during this time period a data yield of about 74% was achieved. Simulation studies suggest that with two additional GPS receivers, which are scheduled for addition to the network in 2008, about 95% of the transmitted subframes will be retrieved. The message data archive is open to the scientific community for non-commercial purposes and may be accessed through GFZ’s Information System and Data Center ().

G. BeyerleEmail:

  相似文献   

基于"北斗"卫星导航系统的长报文通信协议   总被引：2，自引：0，他引：2  

成方林  张翼飞  刘佳佳 《海洋技术学报》2008,27(1):26-29

"北斗"卫星导航系统已经广泛应用在海洋、气象、水利和农业等领域中,利用短报文方式传输各类观测数据。文中介绍了一个基于"北斗"卫星导航系统的长报文通信协议,很好地解决了利用"北斗"卫星导航系统长报文传输时存在的数据丢包问题。  相似文献   

上海国际航运中心集装箱深水港岩土工程概况     

冯铭璋  陈智勇 《上海国土资源》2001,(1):11-16

文章概述上海国际航运中心集装箱深水港的定位，港址和跨海大桥地区基底地质、区域稳定性及松散堆积层的岩土工程基本特征。  相似文献   

电磁环境对GNSS观测数据质量的影响     

刘佳  陈远  黄林超  周永江  许超钤  刘虎 《北京测绘》2021,35(2):148-151

通过在35、110、220、500、800kV 5种不同电压等级的变电站开展全球卫星导航定位系统(GNSS)观测实验,从数据完整率、多路径、信噪比、观测值与周跳比4项指标对各测试站点的GNSS观测数据质量进行统计分析,研究不同电压等级下电磁环境对各GNSS系统观测数据质量的影响。结果表明:不同电压等级下电磁环境对各GNSS系统的观测数据质量无负影响,该结论为论证变电站建设GNSS连续运行参考站(CORS站)的可行性提供了一定的参考价值,促进了卫星导航定位技术在电力行业的应用。  相似文献   

A VLBI Delay Model for Radio Sources at a Finite Distance     

M. Sekido  T. Fukushima 《Journal of Geodesy》2006,80(3):137-149

A relativistic delay model for Earth-based very long baseline interferometry (VLBI) observation of sources at finite distances is derived. The model directly provides the VLBI delay in the scale of terrestrial time. The effect of the curved wave front is represented by using a pseudo source vector K = (R ₁ + R ₂)/(R ₁ + R ₂), and the variation of the baseline vector due to the difference of arrival time is taken into account up to the second-order by using Halley’s method. The precision of the new VLBI delay model is 1 ps for all radio sources above 100 km altitude from the Earth’s surface in Earth-based VLBI observation. Simple correction terms (parallax effect) are obtained, which can also adopt the consensus model (e.g. International Earth Rotation and Reference Frames Service conventions) to finite-distance radio source at R > 10 pc with the same precision. The new model may enable estimation of distance to the radio source directly with VLBI delay data.  相似文献