A new extended Kalman filter based carrier tracking loop

Abstract

Carrier tracking is the most important unit in GPS the receiver that can decide the performance of the GPS receivers in GPS receivers. To improve the performance of the GPS receiver, we need to mitigate the noise of carrier tracking loop. Kalman filter is a kind of effective method for noise mitigation and it has very good dynamic performance.In the former research on Kalman filter based carrier tracking loop, the system model needs to be improved. However the measurement noise model can not be estimated accurately because of multi-path and measurement thermal noise and they are difficult to decide accurately. Perhaps they will bring the standard Kalman filter based carrier tracking loop some big errors and can not make the best of advantages of Kalman filter because the standard Kalman filter can not adjust the models. For solving of this problem, a kind of innovation based adaptive extended Kalman filter is addressed and a new system model is put forward. They are applied to the carrier tracking loop in the paper. The extended Kalman filter base carrier tracking loop is also effective to restrain the output distortion of the discriminator. The validation experiments were designed and finished. The experimental results are good to prove the effectiveness of the EKF based carrier loop. The results show that the EKF based carrier loop has much better anti-noise performance, and the anti-noise performance and the sensitivity of the GPS receiver with the EKF based carrier loop are improved obviously.