Research On BD-?/GPS Satellite Integrated Positioning Method

Satellite positioning system plays an important role in economic development and national interests safeguard, therefore every country attaches high importance to the development of satellite positioning system. The construction of Beidou satellite system promotes the development of China's satellite positioning technology which has long-term significance for the applications in the areas of military and civilian. With the establishment and improvement of satellite positioning system in many countries, the technology and application of several major satellite systems have become the research focus of international scholars. Based on the idea that measurement information of BD-2 and GPS can be used to improve the positioning performance of the system, several key issues of BD-2 and GPS satellite positioning systems are discussed in this paper.Firstly, the basic components, the current status and future development trends of BD-2 and GPS systems are introduced respectively; the constellations characteristics and signal parameters of BD-2 and GPS systems are emphatically analyzed. The similarities and differences between the two systems are summarized in order to analyze the feasibility of the combination of BD-2 and GPS. Through simulation, the compatibility of public signal and interaction for overlapping signal is analyzed, and the processing method of BD-2 and GPS systems with different times and different coordinates is given.Secondly, the error sources of BD-2/GPS satellite integrated system are discussed in detail, and the solutions to eliminating, correcting or suppressing each error source are given.The mathematical model of BD-2/GPS satellite integrated system is established and the positioning solver of BD-2/GPS is calculated by using the weighted least squares method.According to the constellation parameters of BD-2 system, constellation for BD-2 system is built by using STK simulation software and its positioning performance is also analyzed. The positioning performances of BD-2 system, GPS system and satellite BD-2/GPS satellite integrated system all over the world as well as in Harbin are simulated. It can be concluded from the simulation results that the BD-2/GPS satellite integrated system has significantly better performance than the single system in the number of visible stars and positioning accuracy.Finally, due to the fact that the number of visible stars for BD-2/GPS integrated satellite system increases greatly, the satellite selection algorithm used in BD-2/GPS satellite integrated system is improved in this paper in order to weigh the amount of computation for positioning solver and positioning accuracy. Through simulation, the differences between satellite selection algorithm based on artificial bee colony and the traditional best GDOP value algorithm are discussed in this paper. The results show that under the premise of meeting the positioning accuracy the algorithm greatly reduces the calculation and improves the real-time performance of system.