Carrier Recovery Algorithm Based On Kalman Filter Under Weak Signal Navigation Receiver

Aiming at the growing demand of navigation server need under the weak signal,the receiver should solve the problem of stable tracking in carrier loop?In this paper,carrier recovery algorithm based on Kalman filter under weak signal was studied?The major work is as following:(1) At first, this paper summarized traditional carrier recovery algorithm, analyzed the phase discriminator, the frequency discriminator and the loop filter. Aiming at function shortage of traditional carrier recovery algorithm under the weak signal, using Kalman filter replaced the loop filter, and Kalman filter model is established.(2) Traditional analysis method in carrier loop is based on analog phase-locked loop, and can't fully consider the effect of noise and the integral time. Aiming at this problem, a model of phase discriminator is established. And the Integration time optimization method is proposed combining the phase discriminator and Kalman filter model. Then, According to the analysis of the cycle slip in long integration time and weak signal, a method to restrain cycle slip is proposed.(3) Like phase discriminator, a model of frequency discriminator is established, and frequency Kalman filter model is established too. The Integration time optimization method is proposed combining the frequency discriminator and frequency Kalman filter model.(4) A design of tracking loop with coprocessor is given by this part using the steady-state Kalman filter as loop Filter. To improve the processing ability of coprocessor, a module to pretreat the correlation value was established. The simulation results explain the feasibility of this design.