直扩接收机的伪码二维捕获改进算法

An improved algorithm of pseudo-code two-dimension acquisition for DSSS system

传统的伪码捕获算法已经无法满足伪码的快速捕获的要求,为了降低伪码的捕获时间,在伪码二维捕获的基础上提出一种伪码二维捕获改进算法,该算法包括两级捕获,第一级捕获增大伪码时延和多普勒频差步进量,大范围搜索时延和频差;第二级捕获缩小伪码时延和多普勒频差步进量,小范围搜索时延和频差。理论分析和仿真结果表明,提出的伪码二维捕获改进算法相比伪码二维捕获算法,捕获时间缩短为原来的一半,捕获到的伪码时延和多普勒频率的性能有所改善。

Traditional pseudo-code acquisition algorithm is unable to meet the requirements of the fast acquisition of the pseudo-code, in order to reduce the acquisition time of the pseudo-code, based on the algorithm of pseudo-code two-dimension acquisition, this paper presents an improved algorithm of pseudo- code two-dimension acquisition. The algorithm consists of two stage, the first stage increases the steps of pseudo-code delay and Doppler frequency shift in a wide range, the second stage narrows the steps of pseudo-code delay and Doppler frequency shift in a small range. The theoretical analysis and simulation results show that the improved algorithm of pseudo-code two-dimension acquisition compared to the algorithm of pseudo-code two-dimension acquisition reduces the acquisition time by half and improves the performance in delay and Doppler frequency shift.