BDS接收机捕获与跟踪方法的研究

发布时间：2018-05-24 10:48

本文选题：BDS + BOC　；参考：《南京理工大学》2014年硕士论文

【摘要】：北斗卫星导航系统简称北斗系统(BeiDou Navigation Satellite System,简称BDS), BDS是继美全球定位系统(GPS)、俄GLONASS以及欧盟的Galileo之后,我国自行研制开发的卫星导航系统。首先对BDS信号的特点及调制方式进行了研究,通过与传统BPSK信号的对比,分析研究了BOC信号调制方式的相关函数、功率谱密度等特点。虽然BOC相关函数峰值陡峭可以提高捕获精度,但是会出现多峰现象,因此,研究消除多峰的算法来提高精度是捕获阶段的一个主要研究问题。接着重点对ASPeCT方法进行深入研究,通过仿真实验论证其可以有效消除捕获的多峰现象及提高捕获精度。同时,利用ASPeCT技术,还可以消除鉴相模糊点。最后,通过实验对比论证了利用三次样条插值可以有效提高捕获精度。在跟踪阶段,深入研究了载波环和码环。重点研究了载波环中的锁相环(PLL)和锁频环(FLL)和环路阶数的选择对跟踪过程的影响,以及码环的延迟锁定环路原理(DLL)。在这两个反馈调节环路中,针对环路动态性、噪声等影响因素,研究了带宽和环路阶数,并且详细分析研究信噪比、鉴相方式和积分时问对环路的影响。通过ASPeCT技术对鉴相器进行设计,实验验证其可以消除鉴相结果出现的跟踪模糊点问题从而提高跟踪精度。最后,通过模拟实验,对比研究了二阶FLL辅助三阶PLL和传统二阶PLL锁相环的跟踪多普勒频移、鉴别器码相位误差和即时相关峰输出等图形,得出使用二阶FLL辅助三阶PLL可以提高跟踪性能。
[Abstract]:The Beidou satellite navigation system is called the BeiDou Navigation Satellite System (BDS), and BDS is a satellite navigation system developed by our country after the United States global positioning system (GPS), Russia GLONASS and the European Union Galileo.
Firstly, the characteristics and modulation modes of BDS signal are studied. By comparing with the traditional BPSK signal, the correlation function of the modulation mode of the BOC signal and the power spectrum density are analyzed and studied. Although the peak of the BOC correlation function is steep, the acquisition precision can be improved, but the multi peak phenomenon will appear. Therefore, the algorithm to eliminate the multi peak is improved. The precision is a major problem in the acquisition stage. Then, the ASPeCT method is deeply studied. Through the simulation experiment, it is proved that it can effectively eliminate the captured multi peak phenomenon and improve the acquisition precision. At the same time, using the ASPeCT technology, the phase discrimination fuzzy points can be eliminated. Finally, the three spline interpolation is proved by the experimental comparison. The acquisition precision can be improved effectively.
In the tracking stage, the carrier ring and the code ring are deeply studied. The influence of the selection of phase locked loop (PLL) and frequency lock loop (FLL) and loop order in the carrier ring on the tracking process and the principle of the delay locking loop (DLL) of the code ring are studied. In these two feedback loops, the bandwidth is studied for the influence factors of the loop dynamics and noise. And the loop order, and detailed analysis of the signal-to-noise ratio, phase detection method and the influence of the integral time on the loop. Through the ASPeCT technology, the phase detector is designed. The experiment proves that it can eliminate the tracking fuzzy point problem appearing in the phase detection result so as to improve the tracking precision. Finally, the two order FLL auxiliary three order PLL is compared through the simulation experiment. With the traditional two order PLL phase locked loop tracking Doppler frequency shift, discriminator code phase error and instant correlation peak output, it is concluded that the use of two order FLL assisted three order PLL can improve the tracking performance.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN96.1

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