基于单元相关的GPS L1C/A与L1C联合捕获算法

GPS L1C/A-L1C combined acquisition algorithm based on unit correlation

传统的全球定位系统(global positioning system,GPS)L1C/A码信号和新型L1C信号同处于L1频段(1575.42MHz),充分利用了有限的频带资源。基于此特点,针对GPS L1C/A和L1C信号联合捕获中多相关峰引起的误捕问题,提出一种新的单元相关的方法。将本地L1C/A和L1C码序列分别拆分为奇、偶两个单元信号,对单元信号与接收信号的单元相关函数进行重组,完全消除L1C/A码信号引起的9个次峰,提高主峰峰值,得到尖锐的窄相关峰。仿真结果表明,该方法得到的相关峰跨度为0.5个码片,大大提高捕获精度,且捕获灵敏度比单通道联捕提高约2dBHz,同时算法复杂度低,可应用于工程实际。

The traditional global positioning system （GPS） L1C/A code signal and the new LIC signal are both in L1 band （1 575.42 MHz）, which makes full use of the limited frequency band resources. A new com- bined acquisition based on unit correlation is proposed, for the multiple peaks in the combined acquisition of GPS LIC/A and L1C signal. Local LIC/A code and L1C sequence are divided into an odd unit signal and an even unit signal respectively. Then, the unit correlation functions of unit signals and the received signal are reconstruc- ted, so that nine sub-peaks caused by LIC/A code signal are completely eliminated, and the main peak value is improved to obtain a sharp narrow correlation peak. Simulation results show that, the span of correlation peak with the proposed method is 0.5 chip, which greatly improves the acquisition accuracy, and the acquisition sen- sitivity is about 2 dB higher than that of the combined acquisition with the single channel. Besides, this algo- rithm has a lower complexity and can be applied to engineering practice.