一种基于差分相关的DS/FH信号快速捕获方法

A rapid acquisition method for DS/FH signal based on differential correlation

针对DS/FH信号的参数不确定性高、捕获困难的特点,本文提出了一种基于差分相关的捕获方法。该方法利用差分相关的算法去除接收信号的载波频率,只需要一次伪码并行搜索运算,即可获得输入信号的伪码相位,利用已知伪码对接收信号先进行解扩,然后采用快速傅立叶算法(FFT)检测载波频率,估计出跳频频率和多普勒频率值。该方法将DS/FH信号捕获时对跳频频率、多普勒频率、伪码相位三维搜索过程变为伪码相位的一维搜索和跳频频率、多普勒频率的估计过程,理论分析和算法仿真证明该算法相对基于FFT的载波并行捕获法减少了捕获的计算量,实现DS/FH信号的快速捕获。

For the high uncertainty parameters and difficult capture of DS/FH signal, this paper proposes a capture method based on differential correlation. The method uses a differential correlation algorithm to remove the carrier frequency of the received signal and get pseudo-code phase of the input signal by only a pseudo-code parallel search operation. Using the known pseudo-code dispreads the input signal, and then using fast Fourier transform(FFT) algorithm detects the carrier frequency and estimates the hopping frequency and Doppler frequency. This method makes the three-dimensional search process of hopping frequency, Doppler frequency and pseudo-code phase into a one-dimensional search process of pseudo-code phase and hopping frequency, Doppler frequency estimation process for DS/FH signals capture. The theoretical analysis and simulation results prove that the method reduces the amount of computation relative to carrier parallel capture based on FFT and achieves rapid capture of DS/FH signal.