伪卫星网络定位系统研究与设计

发布时间：2018-01-01 21:02

本文关键词：伪卫星网络定位系统研究与设计　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：在山谷中的矿区、隧道、高楼密集的"城市峡谷"等特殊场景下,由于卫星信号受到阻挡而无法接收和提供精确的定位服务。伪卫星增强定位系统的出现为解决上述场景下的定位问题提供了可能。目前,国外的Locata伪卫星系统已经投入军事和商业应用,该系统克服了大量传统伪卫星系统中面临的技术难题,如时钟同步、远近效应、多径效应等,在各种复杂环境下的测试结果表明其定位精度已经远远超过其他导航定位系统。本文参考北斗导航系统及Locata伪卫星系统中的相关技术来研究并设计一种伪卫星定位原型系统,为将来进一步研究伪卫星关键技术提供平台支撑。首先,研究了国内外的伪卫星系统发展状况,并参考国外的Locata伪卫星系统详细介绍了伪卫星系统的组成、工作原理以及伪卫星系统中普遍存在的几大关键问题,参考北斗二代导航电文帧结构设计了一种适合伪卫星增强定位系统的导航电文。其次,针对伪卫星定位系统中时间同步问题,参考Locata中TimeLoc技术原理设计、验证了一种基于DDS的解决方案,并预留了供后续研究的相关接口。研究了伪卫星系统中的数字信号处理技术,包括收发机基带数字信号的产生和定位接收机中频数字信号处理。基于FPGA实现了伪卫星信号的捕获、跟踪算法,并进行仿真验证。再次,分析研究了频偏对跟踪环路及信号解调的影响,仿真结果表明本文解决方案在频偏存在的情况下依然能有效地解调出导航电文。本文给出了一种基于FPGA+Nios II软核的设计方案用于后续的导航电文提取以及定位解算,为后续的算法实现提供了平台支撑。接着,给出了伪卫星系统收发机射频前端、定位接收机射频前端方案并分别进行了设计。针对定位接收机给出了一种基于Max2769B集成一体化方案,并基于NiosII软核实现了该芯片的驱动设计,实验结果表明该方案可以作为伪卫星定位接收机方案。最后,本文对各项研究工作进行了总结和展望,并为下一步的研究提出了方向和建议。
[Abstract]:In the valley mining areas, tunnels, high-rise dense "City Canyon" and other special scenes. Due to the blocking of satellite signals, it is impossible to receive and provide accurate positioning services. The emergence of pseudosatellite enhanced positioning system provides the possibility to solve the problem of location in the above scenarios. At present. Locata pseudo-satellite systems abroad have been put into military and commercial applications. The system overcomes a large number of technical problems in traditional pseudo-satellite systems, such as clock synchronization, near-far effect, multi-path effect and so on. The test results in various complex environments show that the positioning accuracy of the system is far higher than that of other navigation and positioning systems. This paper studies and designs a new method based on Beidou navigation system and Locata pseudosatellite system. A prototype system for pseudosatellite positioning. It provides platform support for further research on the key technologies of pseudosatellites. Firstly, the development of pseudosatellite systems at home and abroad is studied. With reference to the Locata pseudosatellite system abroad, the composition, working principle and several key problems in the pseudosatellite system are introduced in detail. According to the frame structure of Beidou second generation navigation message, a kind of navigation message suitable for pseudosatellite enhanced positioning system is designed. Secondly, the time synchronization problem in pseudosatellite positioning system is addressed. Referring to the principle of TimeLoc technology in Locata, a solution based on DDS is verified. The digital signal processing technology in pseudosatellite system is studied. Including transceiver baseband digital signal generation and location receiver if digital signal processing. Based on FPGA pseudosatellite signal acquisition tracking algorithm and simulation verification. The influence of frequency offset on tracking loop and signal demodulation is analyzed. The simulation results show that the solution can demodulate the navigation message effectively in the presence of frequency offset. A new method based on FPGA Nios is presented in this paper. The design of II soft core is used for the subsequent navigation message extraction and location solution. It provides platform support for the subsequent implementation of the algorithm. Then, the RF front-end of the pseudosatellite transceiver is given. The RF front-end scheme of the positioning receiver is designed, and an integrated scheme based on Max2769B is presented for the positioning receiver. The driver design of the chip is realized based on NiosII soft core. The experimental results show that this scheme can be used as a pseudo-satellite positioning receiver. Finally, this paper summarizes and prospects the research work. The direction and suggestion for the next research are also put forward.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN967.1

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