TMBOC信号的P码直捕算法研究与实现
发布时间：2018-10-10 15:25
【摘要】：如今卫星导航已是一个国家综合实力的体现,美国有GPS导航系统,欧盟有Galileo导航系统,俄罗斯有Glonass导航系统,还有正在建设的我国的北斗导航系统。在现有的导航系统中,大多采用直接序列扩频(DSSS)工作方式,而伪随机序列码正是DSSS的关键。本课题主要就周期很长的伪随机序列码即P码进行研究,P码有其优良的特点,周期长,码率高,使得在应用中更难被敌方捕获和解密,因此具有更高的保密性和抗干扰性,在军事领域获得了广泛的应用。常规的P码捕获均是以短周期码(C码)为基础,并结合P码和C码的关系进而实现P码的捕获。这种捕获方法看似比较简单而且容易实现,但是其P码的捕获过多的依赖于短周期码(C码)的捕获,极大的削弱了P码所带来的优势,从而降低了其抗干扰性和保密性。本论文的目标是为我国自主卫星导航定位系统接收机设计在新的信号调制体制下(TMBOC信号)的长周期测距码(P码)直捕模块,即不需要捕获C码,直接对P码捕获,为接收机信号跟踪单元提供其码相位和载波频率的粗略估计,提高卫星导航系统在导航战环境下的对抗能力。论文首先介绍了导航定位接收机的理论基础,即扩频通信理论。由此引申出本文所研究的扩频通信技术中最常见的一种即直接序列扩频通信系统(DSSS),并结合本论文的特点,着重讲述了TMBOC调制信号及长周期测距码(P码)。然后概述了直扩信号捕获的基本模型和捕获算法,并结合P码长周期的特点,对比了几种典型的P码捕获算法,在对其分析比较的基础上选定基于FFT的频域伪码相位并行搜索和匹配滤波+FFT这两种方法来实现P码直捕模块。随后针对选定的两种捕获算法,在对其算法仿真的基础上进行FPGA的设计。文中详细的给出了直捕模块的总体结构、单元子模块的结构、仿真结果及硬件消耗情况。最后,对整篇文章进行总结,提出今后可进一步改善的地方。
[Abstract]:Nowadays, satellite navigation is the embodiment of a country's comprehensive strength. The United States has a GPS navigation system, the European Union has a Galileo navigation system, Russia has a Glonass navigation system, and the Beidou navigation system is under construction in China. In the existing navigation systems, direct sequence spread spectrum (DSS) (DSSS) is mostly used, and pseudorandom sequence code is the key of DSSS. This paper mainly studies the pseudorandom sequence code (P code) which has a very long period. P code has its excellent characteristics, long period and high code rate, which makes it more difficult to be captured and decrypted by the enemy in application, so it has higher confidentiality and anti-jamming. It has been widely used in military field. The conventional P code acquisition is based on short period code (C code), and the relation between P code and C code is combined to realize the acquisition of P code. This acquisition method seems to be simple and easy to implement, but the acquisition of P-code depends too much on the acquisition of short period code (C code), which greatly weakens the advantage brought by P-code and reduces its anti-jamming and confidentiality. The goal of this paper is to design a long period ranging code (P code) direct capture module for the receiver of autonomous satellite navigation and positioning system (TMBOC) under the new signal modulation system, that is, the acquisition of P code without the need to capture C code. For the receiver signal tracking unit, the rough estimation of the code phase and carrier frequency is provided to improve the countermeasure ability of the satellite navigation system in the navigation warfare environment. Firstly, the thesis introduces the theoretical basis of navigation and positioning receiver, that is, spread spectrum communication theory. Thus, one of the most common spread spectrum communication technologies studied in this paper is the direct sequence spread spectrum communication system (DSSS),). Combined with the characteristics of this paper, the TMBOC modulation signal and the long period ranging code (P code) are emphatically described. Then, the basic model and acquisition algorithm of DSS signal acquisition are summarized, and several typical P-code acquisition algorithms are compared according to the characteristics of P-code long period. On the basis of the analysis and comparison, two methods based on FFT are selected to realize P-code direct-trapping module: phase parallel search of frequency domain pseudo-code and matched filter FFT. Then the FPGA is designed based on the simulation of the two selected capture algorithms. In this paper, the overall structure of the direct capture module, the structure of the unit sub-module, the simulation results and the hardware consumption are given in detail. Finally, the article is summarized, and further improvement is put forward.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN967.1
本文编号：2262284
[Abstract]:Nowadays, satellite navigation is the embodiment of a country's comprehensive strength. The United States has a GPS navigation system, the European Union has a Galileo navigation system, Russia has a Glonass navigation system, and the Beidou navigation system is under construction in China. In the existing navigation systems, direct sequence spread spectrum (DSS) (DSSS) is mostly used, and pseudorandom sequence code is the key of DSSS. This paper mainly studies the pseudorandom sequence code (P code) which has a very long period. P code has its excellent characteristics, long period and high code rate, which makes it more difficult to be captured and decrypted by the enemy in application, so it has higher confidentiality and anti-jamming. It has been widely used in military field. The conventional P code acquisition is based on short period code (C code), and the relation between P code and C code is combined to realize the acquisition of P code. This acquisition method seems to be simple and easy to implement, but the acquisition of P-code depends too much on the acquisition of short period code (C code), which greatly weakens the advantage brought by P-code and reduces its anti-jamming and confidentiality. The goal of this paper is to design a long period ranging code (P code) direct capture module for the receiver of autonomous satellite navigation and positioning system (TMBOC) under the new signal modulation system, that is, the acquisition of P code without the need to capture C code. For the receiver signal tracking unit, the rough estimation of the code phase and carrier frequency is provided to improve the countermeasure ability of the satellite navigation system in the navigation warfare environment. Firstly, the thesis introduces the theoretical basis of navigation and positioning receiver, that is, spread spectrum communication theory. Thus, one of the most common spread spectrum communication technologies studied in this paper is the direct sequence spread spectrum communication system (DSSS),). Combined with the characteristics of this paper, the TMBOC modulation signal and the long period ranging code (P code) are emphatically described. Then, the basic model and acquisition algorithm of DSS signal acquisition are summarized, and several typical P-code acquisition algorithms are compared according to the characteristics of P-code long period. On the basis of the analysis and comparison, two methods based on FFT are selected to realize P-code direct-trapping module: phase parallel search of frequency domain pseudo-code and matched filter FFT. Then the FPGA is designed based on the simulation of the two selected capture algorithms. In this paper, the overall structure of the direct capture module, the structure of the unit sub-module, the simulation results and the hardware consumption are given in detail. Finally, the article is summarized, and further improvement is put forward.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN967.1
【参考文献】
相关期刊论文 前1条
1 庞统;张天骐;赵德芳;金翔;;基于部分相关和全相位预处理的伪码快速捕获方法[J];计算机应用研究;2011年06期
，本文编号：2262284
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