低轨卫星直扩通信系统快速码捕获算法的设计

直接序列扩频用于低轨卫星通信可以解决抗敌意干扰问题,但多普勒频移下码捕获是需要解决的关键技术。基于离散时间信号处理分析了多普勒频差对码捕获性能的影响,给出部分匹配滤波器与FFT结合的码捕获算法原理。针对大频差、长地址码直扩系统的快速码捕获问题,提出了一种二次部分匹配滤波器与FFT结合算法的实现方案,在考虑捕获性能与实现复杂度之间的折衷上,具有很强的灵活性。

Design of Fast Code Acquisition for LEO Satellite DSSS Communication Systems

Direct sequence spread spectrum (DSSS) can be used for anti-jamming communication in low-earth-orbit (LEO) satellite systems. However, code acquisition in Doppler offset is the key technique. In this paper, based on the discrete-time signal processing, the representations of Doppler effect on code acquisition performance is analyzed and the principle for the code acquisition algorithm combining partial-matched filter with FFT is given. We design a fast code acquisition structure by using twi-partial-matched filter with FFT for the large Doppler offset and long PN code spread spectrum systems. This structure can provide a very good trade-off and flexibility between acquisition performance and complexity.