Performace analysis of signal tracking filter and navigation filter tight integration in GNSS receiver

Vector tracking loop (VTL) can be regarded as a kind of integration of navigation filter and signal tracking. It has a better performance for weak signal and can recapture signal quickly, but its robustness and computation complexity is worse. This paper mainly studies a tight integration model of navigation filter and tracking filter, which remains the signal tracking filter in local channels and with their help, the robustness will be improved. Furthermore, the impact of combinational interval between navigation filter and signal tracking filter on the tracking performance is analyzed, especially about the tracking accuracy and ability of reacquisition. The conclusion is that the combinational interval is longer, the tracking accuracy is worse, but its computation complexity is lower. The simulation results show that when the integration interval is 0.1s, the frequency tracking accuracy of tight integration is better than the convention local tracking filter, and this tight integration also has the ability of fast reacquisition.