The Method Research And Software Realization Of GNSS Multiple System Integration For Short Baseline Solution

With the development of GNSS technology, especially the completion of the second step plan of the beidou satellite navigation system in our country, multi-frequency and multi-system GNSS integration application will become a primary trend of GNSS navigation and positioning; Now the system with the capability of independent service includes the system of GPS, GLONASS and BDS;Multiple system integration can greatly improve the redundancy, the positioning accuracy, the stability of the positioning and the quality of navigation.The main research work of this paper includes the following three parts:Firstly, a main proposal is proposed after studying the multiple system integration theory of time system and coordinate system unification and the method of GNSS satellite coordinates calculation.Secondly, the basic model of GNSS multiple system integration is studied and established.The model includes the mathematical model of single difference and double difference, the stochastic model based on high angle, signal-to-noise ratio and posteriori variance estimation and error modification model of the troposphere and ionosphere.Thirdly, study on key technologies of short baseline solution for GNSS multiple system integration is introduced and implemented. The key technologies include cycle slip, float revolution based on sequential adjustment and kalman filter and fixing ambiguity by LAMBDA.Finally, a software for short baseline solution of BDS/GPS/GLONASS system integration is developed by the use of the algorithm of this paper. The performance of single point pseudorange positioning, pseudorange double difference positioning and carrier double difference positioning of the three systems, GPS, BDS, and GLONASS, and the combined systems, referred to as BDS/GPS, GPS/GLONASS, BDS/GLONASS, and BDS/GPS/GLONASS, is compared and analyzed by experimental data. Then the article draws a conclusion that the positioning accuracy and stability of double system is better than single system in the short baseline solution,with the positioning accuracy achieving centimeter-level, and the three system is better than single system. Therefore, the correctness and practicability of the software is effectively verified.