共查询到20条相似文献,搜索用时 453 毫秒
1.
精密单点定位(Precise Point Positioning, PPP)利用接收机收到的载波相位测量值进行定位,载波相位整周模糊度的固定影响着PPP的收敛速度和定位精度。采用B2a信号替代B2I信号,与B1I、B3I组成三频信号观测值组合,在此基础上对传统Boot-strapping方法加以改进,提出了一种改进的三频模糊度解算方法。该方法采用了超宽巷-超宽巷-宽巷-窄巷的解算策略,通过比较选择波长较长、电离层延迟较小、测量噪声较小的三频观测值组合,分别用于解算超宽巷组合、宽巷组合和窄巷组合的模糊度。当电离层延迟无法忽略时,所提方法通过引入额外的伪距观测量来消除在解算组合模糊度的过程中出现的电离层参数和几何参数的影响。实验表明,所提方法与传统方法在完成一次模糊度解算的时间上相差无几,但是相比于传统方法,所提方法具有更高的模糊度解算成功率。 相似文献
2.
运用全球定位系统(GPS)进行定位导航,已在全球众多领域中得到了广泛的应用。在运用这种定位技术的方法中,伪距测量和载波相位测量得到了广泛的应用。载波相位测量的定位精度比伪距测量的定位精度高出两个数量级,在静态短基线载波相位测量中可达到mm量级的精度,在动态实时定位中可以达到cm量级的精度,所以定位的高精度使其具有了广泛的应用前景。但在载波相位测量中存在着整周模糊度求解的问题,故如何有效、快速、简便而精确地求解整周模糊度就成了一个关键问题。基于GPS两个民用频率,探讨和论述求解整周模糊度的方法。 相似文献
3.
在北斗双频单历元姿态测量解算中,利用载波相位观测量所构建的方程组是亏秩的,同时利用北斗码观测方程来解决亏秩问题的精度无法保证。因此,本文利用双频相位观测值的宽巷组合,采用LAMBDA搜索方法,首先固定宽巷模糊度,待宽巷模糊度全部固定后,利用宽巷模糊度值和载波相位观测值可解算出B1/B2整周模糊度,进而解算单历元下载体的偏航角和俯仰角。仿真结果表明该方法对北斗单历元下的模糊度和载体姿态角的解算具有很高的成功率。 相似文献
4.
5.
全球卫星导航(Global Navigation Satellite System,GNSS)的伪距差分定位由于不需要解算整周模糊度,即使是在载波差分定位技术广泛应用在高精度差分定位的当代,伪距差分定位在辅助载波差分定位等方面依旧具有研究的意义。本文介绍了一种基于单差正交模型的伪距差分定位技术。它可以避免双差伪距所带来的观测量强相关和对参考卫星过分依赖的缺点,同时消除钟差项的影响。实验结果表明,码差分在动态定位时可以实现分米级的定位精度,可以用于辅助载波差分定位的快速解算。 相似文献
6.
7.
8.
9.
10.
11.
12.
13.
伪卫星远近效应分析与研究 总被引:1,自引:1,他引:0
伪卫星技术在改善和增强卫星导航系统定位性能等方面起到极其重要的作用。在应用中,常常会遇到时间同步、远近效应和几何精度衰减因子等问题。介绍了伪卫星应用中远近效应问题和常用的解决方案,重点分析了采用时分多址技术来进行伪卫星信号设计的问题。通过研究证明,采用时分多路复用更适合远近效应问题的解决。对伽利略伪卫星的脉冲调制进行了研究,得出了适合伽利略信号的脉冲调制占空比参数。 相似文献
14.
15.
Vervisch-Picois A. Samama N. 《Selected Topics in Signal Processing, IEEE Journal of》2009,3(5):810-820
The widespread use of the personal navigation devices makes indoor positioning a major technological issue. The development perspectives of location-based services dramatically increase the importance of developing adequate solutions. In this paper, we carry out a theoretical study of an indoor positioning technique based on time-delayed Global Navigation Satellite Systems (GNSS) repeaters. It is a simple solution deploying minimal infrastructure which can use either outdoor repeated Global Positioning System (GPS) signals or a single signal generator. However, the positioning method presents limitations in terms of correlation and tracking performances. The paper presents theoretical approaches in order to overcome the interference problems and to improve the quality of the GPS signal reception. The new system based on ldquorepealitesrdquo (that comes from repeater and pseudolite) makes the best use of repeater and pseudolites in order to allow a fair continuity of the GNSS service indoors. 相似文献
16.
In the various infrastructure-based indoor positioning systems using Global Navigation Satellite System signals, i.e. pseudolites, repeaters, and repealites, there is the need for the terminal to know the positions of the various transmitters. Some techniques have been proposed for high accuracy pseudolite systems, but they require carrier phase measurements and a careful choice of some specific test locations. Other approaches consider that these data are simply available by any means: Of course, this can be achieved through manual distance measurements and the use of maps of the indoor environment. In this paper, we describe a new method that is based on a two-step approach. The first one consists in deploying the system. The second one is the calculation of the position of the transmitters through classic code measurements for a few specific chosen locations. Thus, the system can be deployed without any constraint and the locations of the transmitters calculated through a basic set of elementary measurements. The theoretical method is first described and the resulting accuracy of the position of the transmitters is then evaluated through theoretical calculations. In addition, electromagnetic simulations are carried out in order to estimate the pseudo-range errors of the proposed measurements: The accuracy of the determination of the position of the transmitters is then estimated (note that two receiver tracking loop implementations are considered). Thus, the accuracy of the proposed method is evaluated theoretically and through simulations. 相似文献
17.
Schuchman L. Elrod B.D. Van Dierendonck A.J. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1989,77(11):1709-1727
The future applicability of the Global Positioning System (GPS) to the National Airspace System (NAS) for user navigation and landing support is discussed. Functional characteristics and performance estimates are presented for several GPS enhancements, including the use of a geostationary satellite L -band repeater, a CONUS calibration network, and pseudolites. Analysis results indicate that an enhanced GPS system can meet US Federal Aviation Administration (FAA) enroute/terminal area navigation and nonprecision approach requirements under conditions which include accuracy degradation due to worst-case satellite failure, selective availability, and signal integrity. Similarly, it is shown that a Category I precision approach and landing requirement is essentially met using two pseudolites per airport. Additional analysis and extensive testing are required to validate the Category I findings 相似文献
18.
Helmut Blomenhofer Günter W. Hein David Walsh 《International Journal of Satellite Communications and Networking》1994,12(5):489-497
Successful GPS on-the-fly (OTF) carrier phase ambiguity resolution for precise positioning at the centimetre level has already been demonstrated. This has usually been in good observation conditions, e.g. over short distances, lots of satellites, P-code pseudoranges available, and small unmodelled errors. In order for GPS to fulfil the rigorous ICAO Cat. III precise landing navigation requirements centimetre-level accuracy must also be obtained in more realistic conditions, e.g. A-S on, high-unmodelled errors and less than six satellites. Integrating GPS with other sensors, e.g. INS, is likely to aid ambiguity resolution in such conditions, but there are limitations. After discussing critically the OTF methods, approaches are examined which will provide the precise accuracy, reliability and integrity required. Combining GPS with one, or more, pseudolites to provide an extra geometrical constraint to aid ambiguity resolution is described. Flight tests using different configurations of pseudolites are carried out and analysed. 相似文献
19.
为了搭建用于室内定位的伪卫星室内定位系统,设计了一个伪卫星用于发射模拟GPS卫星定位信号。从伪卫星的硬件结构的角度详细说明了该伪卫星的各部分硬件组成以及相应的功能。该伪卫星使用了AD9361射频捷变收发器将时钟小数分频、数模转换、信号调制、上变频融为一体,简化了伪卫星的硬件结构。介绍了该伪卫星生成的信号的具体结构,采用时分多址(Time Division Multiple Access,TDMA)技术使得接收机接收伪卫星信号时不会被阻塞。利用示波器、频谱仪和嵌入式逻辑信号分析仪Signal Tap对伪卫星进行测试,包括时钟频率、伪码、BPSK调制、TDMA技术等,结果表明伪卫星工作正常,其信号能被ublox正常接收,可以利用其进行下一步伪卫星组网用于室内定位。 相似文献
20.
伪卫星可提高卫星导航系统在遮蔽环境中的信号覆盖性。地基伪卫星信号仰角低,将导致更为严重的多径影响,不仅会造成较大的伪距测量值误差,而且由多径产生的功率相消会导致信噪比不足,导致接收机的失锁,造成伪卫星信号不可用。针对多径导致的地基伪卫星信号不可用影响,研究信号发射分集技术在地基伪卫星中的应用,对几种典型的发射分集方式进行理论分析和性能仿真。仿真结果表明,通过信号发射分集实现多导航信号相互补充,提高了覆盖区域内地基伪卫星信号的可用性。 相似文献