基于并行架构的宽带扩频信号捕获技术研究

Research on wideband spread spectrum signal acquisition technology based on parallel architecture

摘要:

为解决大动态低信噪比环境下，由于宽带扩频信号速率过快，使得载波多普勒和伪码多普勒较大导致无法成功捕获信号的问题，提出一种基于并行架构的捕获方法；该方法利用并行载波NCO产生本地载波，与接收信号进行下变频混频以对载波和伪码多普勒进行补偿，利用并行伪码NCO产生本地码进行内码滑动相关和外码匹配滤波，经过二次捕获进一步估计载波多普勒和伪码相位；仿真结果表明，在62 dBHz的载噪比下，符号速率为1 Mbps，载波多普勒搜索范围为± 800kHz，载波多普勒变化率为±100 kHz/s时，这种方法可以实现宽带扩频信号捕获，并且在符号信噪比为2 dB时，捕获概率为99%，捕获时间为0.9009 s；使用该捕获方法，可以降低宽带扩频信号捕获复杂度、提高捕获效率，为大动态低信噪比环境下宽带扩频信号的捕获提供了一种有效的捕获方法。

Abstract:

In order to solve the problem that the carrier Doppler and PN code Doppler cannot be successfully captured in the environment of large dynamic and low SNR due to the high rate of wideband spread spectrum signal, a parallel architecture based acquisition method is proposed.This mryhod uses the parallel carrier NCO to generate the local carrier, and perform down conversion mixing with the received signal to compensate the carrier and pseudo code Doppler. Using the parallel pseudo code NCO to generate the local code for internal code sliding correlation and external code matching filtering. Using the secondary acquisition to further estimate the carrier Doppler and pseudo code phase. The simulation results show that under the carrier noise ratio of 62 dBHz, when the symbol rate is 1Mbps, the carrier Doppler search range is ± 800 kHz, and the carrier Doppler change rate is ± 100 kHz/s, this method can achieve broadband spread spectrum signal acquisition. When the symbol signal noise ratio is 2 dB, the acquisition probability is 99%, and the acquisition time is 0.9009 s. The acquisition method can reduce the acquisition complexity of wideband spread spectrum signal and improve the acquisition efficiency, providing an effective acquisition method for wideband spread spectrum signal acquisition in large dynamic and low SNR environment.