复杂环境下的卫星导航增强技术研究

发布时间：2018-03-20 20:21

本文选题：卫星导航　切入点：差分定位　出处：《南京航空航天大学》2013年硕士论文　论文类型：学位论文

【摘要】：卫星导航系统在民用和军用中发挥着越来越重要的作用，但由于卫星导航的易受干扰性，导致在某些特殊情况下，卫星导航定位精度会有所降低甚至完全不可用，导航信号的增强势在必行。本文设计了两种卫星导航增强的方法，一种是无干扰下的差分增强定位，通过两个CC50-BG双系统卫星导航模块获得的观测量进行伪距差分数据处理，实现了近距差分定位；另一种是有干扰下的卫星广播信号上重叠发射卫星导航校正数据和测距信号的异频增强，将差分校正数据经过扩频后发射出去，与卫星广播信号进行频谱重叠，一起经卫星转发。第一种方法中，分析CC50-BG卫星导航模块数据采集原理及数据格式，在Matlab中对采集的数据进行读取，分别生成用户文件和星历文件，并利用星历文件对信号发射时刻卫星位置进行求解，，利用用户文件中的伪距和时间等观测量及卫星位置进行差分定位，在Matlab中设计出差分定位界面并给出差分定位精度。数据表明：在特定的近距实验测量点，GPS卫星平滑差分增强定位对于高度方向的精度改善程度达60%左右。第二种方法中，分析频谱重叠原理，拟选用世广卫星信号来掩护差分增强信号，给出两信号的数学模型，设计了两信号频谱重叠发射系统。设计出差分接收机，差分接收机通过串行干扰抵消的方法从混合信号中提取出差分增强信号，并用软件接收机对提取出的信号进行测试。通过参数设计和性能仿真，可知差分增强信号对广播信号的接收解调影响很小，差分接收机对提取出的差分增强信号实现解扩与辅助测距，解扩得到的差分校正数据可直接用于差分定位。当混合功率比为26dB时，捕获概率达99.99%，测距精度为10.67m，表明了此方法的可行性。
[Abstract]:Satellite navigation systems play a more and more important role in civil and military applications. However, due to the vulnerability of satellite navigation to interference, the positioning accuracy of satellite navigation may be reduced or even completely unavailable in some special cases. It is imperative to enhance the navigation signal. In this paper, two methods of satellite navigation enhancement are designed, one is differential enhanced positioning without interference, and the pseudo-range differential data is processed by two CC50-BG dual-system satellite navigation modules. The short distance differential positioning is realized; the other is the enhancement of the different frequencies of the satellite navigation correction data and the ranging signal on the interference satellite broadcast signal, and the differential correction data is transmitted out after spread spectrum. Overlaps the spectrum with the satellite broadcast signal and transmits it together via the satellite. In the first method, the principle and format of data acquisition in CC50-BG satellite navigation module are analyzed. The collected data are read in Matlab, and user files and ephemeris files are generated respectively. The satellite position is solved by ephemeris, and the pseudo-range and time in the user file are used to locate the satellite. The differential positioning interface is designed in Matlab and the accuracy of differential positioning is given. In the second method, the principle of spectrum overlap is analyzed, and the differential enhancement signal is chosen to cover the signal of Shiguang satellite. The mathematical model of the two signals is given, and the spectrum overlapping transmitting system of two signals is designed, and the differential receiver is designed. The differential receiver extracts the differential enhancement signal from the mixed signal by the method of serial interference cancellation, and tests the extracted signal with the software receiver. The difference enhancement signal has little effect on the reception and demodulation of the broadcast signal, and the differential receiver realizes despreading and auxiliary ranging to the extracted differential enhancement signal. When the mixing power ratio is 26dB, the acquisition probability is 99.99m and the ranging accuracy is 10.67m. the feasibility of this method is demonstrated.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P228.4

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