北斗双频接收机快速热启动策略研究

发布时间：2018-01-26 12:49

本文关键词： 北斗双频接收机热启动首次定位时间比特跳变快速捕获　出处：《北京理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着我国自主研发的北斗卫星导航系统的不断完善以及包含北斗B1与B2民用频段信号信息的空间信号接口控制文件公布,北斗双频接收机因其定位精度高的特点,也得到广泛应用。热启动是最为常用的一种接收机启动方式,随着技术的发展,用户对于接收机热启动速度和精度要求也随之提高。而双频接收机由于捕获搜索范围加倍,增加了常规热启动时间,存在较大的信息滞后,一定程度上影响了双频接收机的性能。因此,为了在减少北斗接收机热启动时间的同时保证较高的初始定位精度,本文主要对北斗双频接收机的快速热启动策略进行研究。本文针对北斗双频接收机的热启动过程,实现了两点策略改进。针对现有预测卫星信号发射时间的快速热启动方法中卫星位置估计值存在较大误差的问题,给出了一种改进方法,将较为精确的传输时间估值带入卫星位置计算,并考虑电离层误差,以减少因卫星位置估计误差导致的接收机定位误差。同时实现了热启动中使用北斗B1频点辅助B2频点的捕获方法,利用同一颗卫星两频点信号多普勒频偏的关系,通过改变捕获通道的分配方式,进一步减少首次定位时间(Time to First Fix,TTFF)。针对热启动中捕获北斗信号D1导航电文时大量存在的比特跳变问题,提出了一种基于本地码拓展的快速捕获方法。首先针对比特跳变问题对信号捕获结果的影响进行分析,指出对于常用的多次捕获方法,比特跳变发生在积分区间中部并非最坏情况。随后提出了一种基于本地码拓展的快速捕获方法,该方法通过拼接和补零重构本地码序列并设计相应的判决器,能够消除比特跳变引起的相关峰分裂,同时增加积分增益。通过使用蒙特卡洛仿真和实际信号捕获测试,验证了该方法针对比特跳变发生频繁的北斗D1导航电文信号具有很好的捕获效果。最后在基于EP2S90F1020和TMS320C6713的北斗双频接收机系统上实现了本文提出的策略。经过实验验证,本文提出的快速热启动策略较常规热启动策略具有更短的首次定位时间,且首次定位结果精度较高,为后续的理论研究和工程实现奠定了良好的基础。
[Abstract]:With the continuous improvement of the Beidou satellite navigation system which is independently developed in China and the publication of the spatial signal interface control file which contains the signal information of Beidou B1 and B2 civil frequency band. Beidou dual-frequency receiver is also widely used because of its high positioning accuracy. Hot start is the most commonly used receiver startup, with the development of technology. The user's request for the receiver's hot start speed and precision also increases, while the dual frequency receiver's acquisition search range is doubled, the conventional hot start time is increased, and there is a large information lag. To some extent, the performance of dual-frequency receiver is affected. Therefore, in order to reduce the hot start time of the Beidou receiver and ensure a high initial positioning accuracy. In this paper, the fast hot start strategy of Beidou dual-frequency receiver is studied, and the hot start process of Beidou dual-frequency receiver is studied in this paper. In order to solve the problem of large error in the estimation of satellite position in the current fast hot start method for predicting the launch time of satellite signal, an improved method is presented. A more accurate estimation of transmission time is introduced into the satellite position calculation, and ionospheric errors are taken into account. In order to reduce the receiver positioning error caused by the satellite position estimation error, the acquisition method using Beidou B1 frequency point to assist B2 frequency point in hot start is realized. Using the relationship of Doppler frequency offset of two frequency points of the same satellite, the first time to First Fix is further reduced by changing the allocation of the acquisition channel. TTFFN. In order to solve the problem of bit hopping in hot start to capture the Beidou signal D1 navigation message. In this paper, a fast acquisition method based on local code extension is proposed. Firstly, the influence of bit jump problem on signal acquisition results is analyzed, and the commonly used multiple acquisition methods are pointed out. Bit hopping occurs in the middle of the integral interval is not the worst case. Then a fast acquisition method based on local code extension is proposed. This method reconstructs the sequence of local codes by splicing and adding zeros and designs the corresponding decider. It can eliminate the correlation peak splitting caused by bit jump and increase the integral gain by using Monte Carlo simulation and real signal capture test. It is verified that this method has a good capture effect for the Beidou D1 navigation message signal which occurs frequently in bit hopping. Finally, the Beidou dual frequency based on EP2S90F1020 and TMS320C6713 is used. The proposed strategy is implemented on the receiver system. The fast hot start strategy proposed in this paper has shorter initial positioning time and higher accuracy than the conventional hot start strategy, which lays a good foundation for subsequent theoretical research and engineering implementation.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN965.5

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