伪码捕获和多普勒频移容限扩展的方法

摘要

In the DBPSK high dynamic burst spread spectrum communication system,Doppler shift has the impact on PN-code acquiring and data demodulation.In order to reduce time of PN-code and Doppler shift acquisition and reduce resource consumption and wrong judgment and avoid polarity reversal of demodulation data,PN-code is acquired through single channel matched-filters,parallel multi-channel is used in the data demodulation branch channel and estimates exactly the frequency using traditional (CPAFC)Cross Product Automatic Frequency Control with 1/4 data rate discriminate range and Doppler tolerance is small.A method is proposed to polarity reversal of demodulation data,combined with the simulation result,double the Doppler tolerance of data demodulation branch channel by using data frame header.%在DBPSK高动态突发扩频通信中,伪码的捕获和数据解调受多普勒频移的影响.为了缩短伪码和多普勒频移捕获时间,降低资源消耗和误判率,避免解调数据极性反转,伪码捕获时采用了单通道匹配滤波器,数据解调支路采用了并行多通道相关器进行多普勒频率粗估计,再利用叉-点积法进行频率精估计,但传统的叉-点积法鉴频范围仅为数据数率的1/4,多普勒频移鉴频容限较小,针对这一缺点,本文采用了数据帧头去避免叉-点积鉴频法中的解调数据符号反转的方法,结合数据仿真结果可知,将数据解调支路的多普勒鉴频容限扩大一倍.