Research On The Synchronization Of Satellite Positioning Receiver

Satellite navigation and positioning system relates to a country's political, economic, military fields, and it is very meaningful to protect national interests. In the Satellite navigation and positioning system, receiver is the part directly facing to the user, and the synchronization determines positioning receiver's performance and implementation of all functions, so the research on the synchronization of satellite positioning receiver is very important. Paper mainly discussed the satellite positioning receiver's synchronization theory with using the example of BD-1 and BD-2. The major contributions of the dissertation include:For the Pseudo-code synchronization, focus on how to improve PN code synchronization and phase measurement precision. Main factors that affect synchronization precision and Different requirements from active localization way and passive localization way were analyzed.Designed two different PN synchronization and phase measurement algorithm in conditions of low sampling rate. In condition of Commensurate sampling, realized the accurate estimate of PN code phase with the method of least-square linear fitting .Designed two channels signal time subtraction measuring algorithm was successfully applied in BD-1 receiver. In conditions of the signal power P =- 152.6dbW, the time subtraction measurement accuracy is 5ns; Successful used Non-commensurate sampling (NCS) theory to design the NCS PN code synchronization and phase measurement algorithm. Especially, the theory and design for high-precision code NCO were discussed in detail. The algorithm was successfully applied in BD-2 receiver. When code rate was10.23 MHz and signal power was- 133dBm, PN code phase measurement precision was less than 1ns (0.01 chip), that well meet the system's requirements. Algorithm can also be used in space distance measurement.For the Carrier synchronization. Analyzed the different demands of active localization way and passive localization way. Designed two carrier tracking algorithm. The AFC carrier tracking method obtained offset size and polarity from the PLL's output, then adjusted the local VCO through the AFC to reduce the residual Frequency offset. This algorithm was successfully applied in BD-1 receiver. FLL/PLL automatically switched carrier tracking algorithm realized switching through the threshold judgment. and it could adapt to different dynamic conditions. The algorithm was successfully applied in BD-2 receiver. Can satisfied BD-2 system dynamic performance requirements(300m/s,4g). When signal power was -133dBm, the precision of Doppler frequency measurement was 0.7 Hz.For the information synchronization, paper introduced information format of the major satellite positioning system and summarized all their similarities, designed universal bit synchronization algorithm and frame synchronization algorithm. The simulation result of bit synchronization and frame synchronization was presented .In this paper, theoretical analysis, simulation, hardware implementation, performance testing were also discussed in detail. These synchronization algorithms has been successfully applied in BD-1, BD-2 positioning receiver, well meet the system performance requirements.