高动态短时突发扩频信号的快速捕获

针对低信噪比和大多普勒频移环境下,短帧突发直接序列扩频通信系统要求在短时间内以很低虚警和漏警概率捕获信号这一难题,设计了仅使用独特码的短时突发扩频信号帧结构,在接收端将扩频码与独特码作为一个复合扩频码看待,提出了基于FFT的高动态突发信号捕获方法,可同时快速完成突发信号检测、扩频码捕获、频偏估计、帧同步检测和位定时捕获等任务。仿真结果表明:该算法能有效消除多普勒频移对短时突发扩频信号捕获性能的影响。

Fast Acquisition of High Dynamic and Short-Term Burst Spread Spectrum Signal

The short term burst spread spectrum signal acquisition with very low false alarm and miss probability in a limited period of time is difficult under low SNR and high dynamic environment. The frame structure containing only unique code of short term burst spread spectrum signal is proposed and designed. The pseudo code and unique word is treated as a compound code by receiver. The burst signal reception method to deal with high dynamic signals based on FFT is provided. The algorithm is capable of completing burst signal detection, PN code acquisition, frequency offset estimation, frame synchronization,bit-timing acquisition and other tasks quickly. Simulation results indicate that the proposed algorithm can eliminate the influence of frequency offset effectively.