Abstract:

There is a way of Doppler orbit determination that recovers carrier signal effectively, and measures the Doppler frequency shift precisely when civil codes of satellite navigation signals are not available. For unknown pseudo-code, a method based on phase compensation and data block accumulation is presented to estimate the carrier frequency of the square signal accurately. For codeless navigation satellite identification, a method based on the characteristics of Doppler frequency shift is proposed, and the clock frequency offset of the receiver is received,and the match algorithm based on the three points method is researched. The global match, local elimination strategy is adopt to improve the reliability of satellite recognition. The simulation reveals that codeless carrier frequency estimation error is within 7 Hz, and the number of satellites estimated correctly is 9 or more. Considering the inaccuracy prior parameters and measurement errors, at least 6 satellites are identified correctly, which satisfies the requirement of orbit determination of satellites.