Research On High Precise Measurement Algorithm Of Satellite Positioning Based On Kalman Filter

The BeiDou Positioning system is researched and developed by our country.This system provides location service, time service as well as communication service, and will take an important role in the field of national defense and civil navigation and orientation. This system is a system that based on code divided multi-addressed direct sequence spread spectrum (CDMA DSSS) technique. In DSSS system, the synchronization of Pseudo Noise Code and Carrier wave is a very important technique that can affect the performance of the whole system, because this technique is not only the precondition of receiving information correctly, but also the key of precise positioning under the environment that the object moves dynamically.This paper is finished in the process of research and development of BeiDou receiver. First of all, This paper introduced the principle of sliding correction method that utilized in the loop of code synchronization and advance-delay tracking method that utilized in the loop of carrier wave based on study the theory of synchronization. Then the focus of investigation is on the effect of loop parameters under low signal to noise ratio and high dynamic range environment, such as bandwidth of acquisition and tracking, phase jitter, decision threshold, false warning and acquisition quickly and so on. Base on above analysis, this paper proposed a algorithm that employ a extended Kalman filter to draught the frequency to appropriate scope and adopted the auto-adapted synthesis decision strategy, changeable circuit bandwidth method and phase assistance code tracking technology to realized high precise positioning. Finally, from the angle of system realization, this paper introduced the flow of the baseband synchronization module and debug method. The final signal wave show that this algorithm conforms to requirement of the receiver.This paper proposed a PN code and carrier wave tracking algorithm based on Kalman filter and analyzed module performance. From simulation and realization scope, this paper verified the idea. The result is satisfied.