Squaring and Long Coherent Integration Codeless Tracking Algorithm of GPS Authorized Signals

Quality monitoring of GNSS authorized signals is an important research field. In this paper, squaring and long coherent integration codeless tracking algorithm is proposed to monitor the Doppler frequency of authorized signals. We firstly analyze the signal and noise power after squaring and coherent integration of GPS L1 C/A and P(Y) multi-component signal with a phase difference of 90°. Then squaring and long coherent integration codeless tracking with traditional loop filtering algorithm (such as phase locked loop, frequency locked loop and frequency locked loop assisted phase locked loop) and with Kalman filtering algorithm are proposed to track Doppler frequency of authorized signals. The effectiveness of the proposed codeless architecture is demonstrated using real data collected from GPS satellites. The results supports the validity of the proposed architecture which enables quality monitoring of authorized GPS signals.