大频偏条件下复扩频码的快速捕获算法

目前常见的捕获算法在系统复杂度和捕获速度之间有着难以调和的矛盾,针对这一矛盾,文中提出一种新的基于复码的二维联合捕获算法。该算法根据复码特性巧妙设计全匹配滤波,以节省捕获时间和资源。同时,在相关后进行FFT运算,实现时域与频域的结合,对码相位和多普勒频移进行二维信号搜索的判决。理论分析和硬件实现验证了该方法能够大幅度的减小捕获时间,节约硬件资源,并且在大频偏情况下仍然具有较好的捕获性能,适于S频段星间通信。

A Fast Acquisition Algorithm of Complex Codein Large Doppler Shift

The contradiction between system complexity and acquisition speed commonly exists in current acquisition algorithms. In light of this, the paper proposes a novel two-dimentional joint acquisition algorithm based on complex code. According to the characteristics of complex code, fully matched correlation is designed to save acquisition time and resource. Meanwhile, the combination of time and frequency domain is achieved via FFT calculation, and two-dimentional signal search is judged by matching-code phase and Doppler frequency shift. Theoretical analysis and hardware implementation verify that this method could greatly reduce the acquisition time, save the hardware resource and maintain good acquisition performance in low-SNR and Doppler frequency shift, thus is suitable for S-band inter-satellite communication system.