GPS信号中P码直接捕获技术的研究

Study on the Technique of P-Code Direct Capturing in GPS Signal

GPS是典型直接序列扩频通信的应用,其采用的伪随机序列之一的P码,更加具有很强的抗干扰和保密性能,实现P码的直接捕获对GPS系统的军事用户及我国未来发展自己的卫星定位系统具有重要意义.针对P码多普勒频移大、周期长的特点,本文探讨了缩短载频搜索范围的方法.在此基础上,对P码序列的搜索算法进行了深入研究,并且结合扩展复制重叠技术和均值法,提出了一种更适合P码搜索的算法.

GPS is the application of typical direct PRN, P-code has more.powerful anti-interference sequence spread spectrum communication, As one kind of and secrecy, the implementation of direct P-code capturing is desiable to GPS＇s military users and it is also meaningful for the development of our own satellite positioning system in the future. According to P-code features of large Doppler frequency shift and long code period, the method that shortens the scope of carrier frequency search is studied. On this basis, the algorithm of P-code search is studied, and a better algorithm of P-code search is put forward through integrating the XFAST technique and mean value method.