High Dynamic Carrier Tracking Algorithm Of Software GNSS Receiver

In order to solve the problems of high cost and difficult upgrade for the existing navigation receiver and multiple system receiver, the concept of GNSS software receiver has enjoyed more and more support. The GNSS signals which are received by software receiver assembled in the high dynamic vector have high Doppler frequency, frequency rate and second derivative of frequency. Therefore, GNSS software receiver applied for high dynamic environment needs high dynamic carrier tracking algorithm accordingly. So in this paper, to solve the problems of high dynamic carrier tracking for high dynamic GNSS software receiver, taking GPS software receiver as an example, high dynamic carrier tracking algorithm was studied.This thesis first introduced the structure of GPS signal and the architecture and principles of GPS software receiver, then the focus is set on the traditional method of tracking GPS signal. At the same time through the analysis of the Doppler effect on the carrier frequency and code phase, the paper provides software simulation method of intermediate frequency signals which is output by front-end of GPS software receiver in high dynamic environment.Then, in this paper, on the basis of characteristics of the high dynamic carrier GPS signal, the high dynamic carrier tracking algorithm was studied. After that, the carrier tracking algorithm principle on the lock-locked on the track and Extended Kalman Filter is analysized. Because Extended Kalman Filter (EKF) algorithm has the shortcomings of computing complexly, high cumulative error of estimated parameters, the Uscented Kalman Filter (UKF) Algorithm for estimation of carrier parameters is introduced. On this basis, the EKF and UKF algorithm model of high dynamic GPS receiver are designed for carrier tracking.Finally, this paper simulated the three carrier algorithm. And the results of the simulation showed: in high dynamic environment, all the three algorithm can track carrier of GPS signals successfully. However, from the aspect of performance, it can be compared to see: a joint lock-locked tracking algorithm has the highest mean square error, and UKF is the second, EKF is the last. When in the same situation of tracking the carrier signal, UKF has the lowest probability of missing lock.