高动态下直扩接收机关键模块的设计与仿真*

高动态给扩频信号带来较高的多普勒频移,使伪随机码产生较大的动态时延,很容易造成载波跟踪环和码跟踪环的失锁。为了提高跟踪环路的动态应力,防止跟踪环路失锁,在分析了捕获与跟踪原理的基础上,提出了一种捕获与跟踪的设计方案。该方案捕获采用基于FFT的并行快速捕获算法,载波环采用2阶锁频环FLL(frequency locked loop)辅助3阶锁相环PLL(phase locked loop),码环采用2阶延迟锁定环DLL(delay lockedloop)。MATLAB仿真结果表明,在高达65 g的视距动态应力条件下该设计也能够表现出其精确、稳定的性能。

Design and simulation of key module of DS-SS receiver in high dynamic

High dynamic creats high Doppler shift to spread-spectrum signal and makes Pseudo-random code have a greater dynamic delay,which is likely to cause carrier tracking loop and code tracking loop out of lock.In order to improve the dyn-amic stress of the tracking loop and prevent tracking loop out of lock,this paper presented a design of the acquisition and tracking based on the analysis of the principle of the acquisition and tracking.MATLAB simulation results show the correctness of this design,and even if in a high dynamic conditions,this design can also have a precise and stable performance.