基于软件相关器的GPS跟踪算法研究与实现

研究了适用于GPS软件接收机的软件相关器和信号跟踪算法，包括码跟踪和载波跟踪。为了提高跟踪灵敏度，码鉴别器和载波鉴相器每Nms输出一次鉴别结果，在Nms的间隔时间段内，每1ms采用状态外推算法对相位、多普勒和多普勒导数进行一次外推。跟踪环路采用载波环辅助码环的跟踪方法，提高了码环的跟踪精度和可靠性。利用真实的采样数据，在PC机上用Matlab对该算法进行了仿真，并且在GPS软件接收机平台上得到实现。实验证明，该算法可以实现对c／A码相位和载波频率的精确跟踪，并得到导航数据。

Research and Implementation of Tracking Algorithm Based on Software Correlator

The research focuses on software correlator and signal tracking algorithm applied in GPS software receiver including code tracking and carrier tracking. In order to improve the tracking sensitivity, code phase detector and carrier phase detector output detection result every N ms. At the interval of N ms,phase,doppler and doppler derivative are computed every lms by using state extrapolation algorithm. The carrier-aided code loop is used to improve the tracking precision and reliability. The algorithm is simulated in Matlab based on real data and implemented in the GPS software receiver platform. Experiment proves that the algorithm carries out the accurate tracking function of C/A code phase and carrier frequency, and decodes the right navigation data.