The Pseudo-code And Carrier Tracking In Satellite Positioning System Technology Research

Satellite positioning system is playing an increasingly important role in all aspects of the construction of the modern battlefield and the national economy. The new dynamic performance requirements are brought in when the satellite positioning system is equipped on vehicle or even airplane. In this paper, the satellite positioning system receiver is designed. Particularly, on the basis of the code tracking system, a modified tracking method is put forward. By adding local code pretreatment part, the performance of the code tracking loop is improved. The discriminator not only has the characteristics of a good oddness, but also isolates the impact of the rate differential output. Comparing with the traditional code tracking method, it is made for fast synchronization and maintenance. It also avoids the error of the JPL approximation algorithm.In order to overcome the carrier Doppler frequency shift in notable high dynamic environment, the Fuzzy logic controller is introduced in the carrier tracking loop, formed the loop with FLC. The intelligent filter which is made up of Fuzzy logic controller and loop filter can dynamically verify loop bandwidth. Therefore, the contradiction between the tracking speed and precision is solved. In the design of the tracking loop, the lookup table is widely used. It is helpful for both implementation and the improvement of the speed. According to the different circumstances, by adjusting the control rule and membership function of the FLC, the best design of the system can be available.The simulation results show that the proposed code tracking and reliable carrier tracking subsystem can work together better than the existing design.