摘要
针对直接序列扩频信号捕获过程中可能存在的多普勒频率误捕问题,提出一种可纠正此误捕问题的伪码捕获改进算法.该算法利用首次捕获得到的伪码相位估计值对接收信号进行解扩,再通过快速傅里叶变换(FFT)对解扩后的信号进行多普勒频率估计,将首次捕获的多普勒频率估计值与FFT结果幅度最大值对应的频率点进行比较,判断是否发生了多普勒频率误捕,如果发生误捕,进行纠正,给出正确的多普勒频率估计值.仿真结果表明,该算法能有效纠正多普勒频率误捕问题,得到正确的捕获结果.
Focusing on a kind of false alarm of Doppler shift in pseudo random（PN） code acquisition module of direct sequence spectrum spreading system（DSSSS） receiver,an improved code acquisition algorithm for correcting false alarm of Doppler shift is presented and analyzed.This algorithm uses the PN code phase estimation to eliminate PN code two-phase modulation effect,then gains Doppler shift estimation by fast Fourier transform（FFT）,and compares the former estimation with the corresponding frequency point of the largest value in amplitude of FFT results.If there is wrong with the Doppler shift estimation,then to give the true value.The simulation results indicated that this improved method is reliable and effective.
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2009年第10期898-901,905,共5页
Transactions of Beijing Institute of Technology
关键词
伪随机码
捕获
多普勒频率
误捕
pseudo random code
acquisition
Doppler shift
false alarm
