The Design And Implementation Of Positioning Algrithm For GPS/BD2 Dual Mode Receiver

With the research and development of more than 30 years,GNSS affects the the military and civil fields deeply. In order to meet the requirements of higher navigation accuracy and performance, and promote the application of BDS in the civil field, using the combined BD system and GPS system will greatly improve the quality of navigation and positioning services. However, as one of the most important error source in GNSS measurement, the multipath effect seriously affects the positioning precision and positioning performance. This thesis focuses on the application of Kalman filter algorithm in the suppression of multipath error. The principle and design of the algorithm are described in detail.At first, this thesis studied the multipath interference residual error distribution of carrier pahse and code phase, which shows that the residuals showing "sustained deviation" and "vibration" two distributon types under multipath doppler effect. Simulation based on LMS DLR multipath channel model verificate the conclusion. Then, according to the residual multipah distribution continued to diverge, the two adjacent time observations are differentiated to elimimate the public deviation error and the differential extended Kalman filter based on multipath error substained deviation distribution is designed. According to the characteristics of the distribution of the multipath residual vibration, the observation residuals after EKF positioning are statistically to estimate the covariance of observation error, and adaptive extended Kalman filter algorithm based on multipath residual vibration distribution is designed. The two algorithm models are implemented by m language on the MATLAB platform and the simulation is carried out. At last, in order to compare the performance of subject localization algorithm and similar products on the market, GPS/BD2 dual-mode receiver verification platform is established based on the same signal source. In the platform, the localization algorithm and positioning calculation module is realized based on C language. The design structure of core module are given.Based on the dual mode receiver verification platform, the multipath mitigation performance of the DEKF and the AREKF algorithm is tested. The test results show that, the average distance error of DEKF compared with EKF, reference module 1, reference module 2 respectively is decreased by 66.80%,73.88% and 79.60%. The positioning accuracy of CEP compared with the EKF algorithm is reduced by 14%, and in 2% slight deviation with reference module 2, stability is better than reference module 1. In urban complex dynamic environment, the positioning performance of AREKF algorithm is better than EKF algorithm, reference module 1, and reach the level of reference module 2.