The Optimal Design And Implementation Of Calculate Methods In GPS Navigation Receivers

This Paper is based on the background of satellite navigation and positioning system, focusing on optimizing methods to improve the calculating speed and precision in the navigation solution process.This article firstly introduced the background and current situation of navigation solution optimizing design, components and processes in navigation solution, and the principle of optimizing. Then focusing on the four aspects of navigation solution, that is, the navigation message parsing, the solution of the satellite position, velocity and time (PVT), the calculation of the speed of high-dynamic targets, the output of solve results, the article analyzed the disadvantages and potential improvements of the classic process method, put forward the optimal design of the program, gave the theoretical analysis, and the actual use of GPS receivers to test verification. As to the navigation message parsing, an optimizing design based on effective verification bit in the general format of the GPS navigation message is presented, using effective rapid-check to determine whether the information is up-to-date and need to be parsed in order to reduce redundant computing. As to satellite PVT Solution, the article puts forward a real-time interpolation method based on the Lagrange interpolation formula, and gives further consideration to the application of fixed-point processor, revises interpolation formula to suit the needs of the fixed-point calculation. As to the calculation of the speed of high-dynamic targets, the classical Kalman filtering approach is introduced. After analysis of filtering model selection of high-dynamic applications, an filtering method assisted by the least-squares (RLS) method is presented to improve the speed calculation precision. An approach to a dynamic adjustment of the filtering parameters is given in the end. As to the optimal design of the output, this design uses interpolation appropriate solution delay count in exchange for more time solving high-frequency output of the method with a lack of the hardware resources, taking into account of abnormal input and the initial parameters of the interpolation program. Finally, the laboratory's GPS receiver is used to assess the whole performance of the optimizing method, the results of the work is summed up and the working directions in the future s proposed.