The Research And Simulation Of Pvt Information Processing Technology Of Gps Receiving System

In recent decades, GPS navigation and positioning technology in both military and civilian development has been booming and widely used in command and control, attacking precise targets, positioning vehicles, monitoring urban traffic, and aircraft navigation and approach landing, etc. However, because GPS satellites often transmit over the fixed frequency and the transmitted navigation signals are relatively weak, military GPS receivers are vulnerable to enemy interference. Therefore, how to improve the positioning accuracy and anti-jamming capability of GPS receivers have become the focus of the study of the GPS navigation and positioning technologies.Based on GPS navigation and positioning, PVT information processing technology of GPS receiving system is embedded researched.This research primarily contains the following four parts. Firstly, based on the study of the structure of Navigation message frame, according to ICD-GPS-200 norm, the ephemeris data in navigation message are interpreted and used as the foundation of solving the instantaneous location of satellite. Secondly, Proceeding from the principle of GPS navigation, based on the precise ephemeris data provided by IGS and the data being received, the source of errors, generated in PVT information processing, is thoroughly analysed, and an error model is established for it, and the analytical results are emulated and tested with computer.Thirdly, aiming at the impact of satellite's geometrical location to positioning accuracy, the visible GPS satellites are selected, and the best combination of constellation is obtained by introducing the method of fuzzy mathematics.. Finally, in dealing with the resolving problem of PVT information, the principle of least-squares and the optimal estimation theory are analyzed and compared in this paper,which discovers that the calculation accuracy of the principle of least-squares is not high, and the convergence rate of the optimal estimation theory is slow. Considering the above presented disadvantages, a new algorithm based on principle of least-squares and the optimal estimation theory is proposed, which makes up the deficiencies of the two methods, and effectively improves the accuracy of calculation and convergence rate.Visual C + + 6.0 development platform are used to set up and achieve simulations respectively based on STK software environment and OEM data acquisition platform.. Simulation results show that by using the algorithms of fuzzy selection and the improved PVT information processing, the positioning accuracy of GPS receiving system is not only improved, the anti-jamming ability of the GPS receiving system is also made possible.