基于时延控制的伪码多普勒补偿算法

Code Doppler compensation algorithm based on delay control

针对高动态或者弱信号条件下,伪码多普勒对卫星导航系统信号捕获的影响将会凸显,导致捕获性能明显降低的问题,提出了一种基于时延控制的码多普勒补偿方法,利用数字延迟滤波器来补偿码多普勒引入的本地码和接收信号的相位不匹配。同时,给出了包括码多普勒补偿在内的新的卫星导航系统信号捕获结构。仿真结果表明:新方法能够很好地进行码多普勒补偿,采用三阶Farrow结构的分数延迟滤波器就可以使捕获损耗降低到0.3 dB以下。

Code Doppler should be compensated under high dynamic or weak signal conditions during Global Navigation Satellite Systems（GNSS）signal acquisition, which will lead to unacceptable acquisition gain loss. Code Doppler is com-pensated by delay control, including integer delay and fractional delay. Its implementation within GNSS signal acquisition based on integer delay lines and the variable fractional delay filter is proposed. The simulation results show that the new method has a perfect performance of compensating code Doppler, and detection loss can be reduced to less than 0.3 dB with a 4th-order fractional delay filter realized by FARROW structure.