Research On BDS/GPS Integrated Positioning Algorithm

Global navigation satellite systems are widely used in earthquake relief,national defense,modern agriculture,smart city and other major areas because of its advantages like high precision,good continuity and so on,but the single system prone to appear some problems like visible satellite number,low positioning accuracy and discontinuity because of bad geomorphological environment or man-made interference.In order to solve this problem,according to the system compatibility and interoperability between GPS and BDS,this paper studies the BDS/GPS positioning algorithm,inc luding the following two parts:(1)Aiming to improve the pseudorange point positioning,the M estimation is introduced to improve the combination mechanism based on traditional Helmet variance component estimation weighting method in this paper,BDS/GPS pseudorange combination weighting algorithm based on prior weight with elevation angle and posterior weight with variance components estimation of M-estimation,and the implementation process is given.During the experiment,the real data is collected by intermediate frequency sampler in two experimental scenarios(open environment,high-rise buildings in the c ity streets),which is processed by software receiver signal,and the visible satellite number,PDOP and positioning error in three directions are compared to demonstrate the effectiveness and robustness of the algorithm;(2)Aiming to improve the carrier phase differential positioning algorithm,BDS/GPS dynamic RTK solution algorithm with Kalman filter is proposed based on carrier phase double difference model,and the state vector,state equation,variance covariance matrix of double difference measurement is designed,to determine the float ambiguities and baseline vector real-time,a specific algorithm implementation process is given.During the experiment,the real data is collected and processed in two experimental scenarios(short baseline and long baseline),and the visible satellite number,fixed rate of single epoch fuzzy,fixed time of first time,baseline results in three directions are compared to demonstrate the effectiveness and efficiency of the algorithm;The experimental results show that the positioning accuracy,robustness or efficiency of BDS/GPS integrated positioning algorithm in this paper are better than that of BDS,GPS single system positioning and traditional BDS/GPS integrated positioning algorithm.The algorithm can reduce positioning blind spots when improving the accuracy of traditional algorithm.The research in this paper has a certain reference value for the design and improvement of multimode receiver,which can provide ideas for the relevant researchers,has strong expansibility and wide application prospect.