Research On Multi-mode Positionin And RAIM

Based on rapid development of GNSS (Global Navigation Satellite System, GNSS) and background of Beidou system (BDS) covering the Asia-Pacific region, this is a research of the theory and method of multi-mode positioning, as well as the receiver autonomous integrity monitoring (RAIM) algorithm. On the basis of the theory introduction, relying on the Hebei Province Continuously Operating Reference Station System (HBCORS), the BDS/GPS regional trial network is built, and real-time and later calculation and analysis is completed with the network of BDS/GPS data, summarized as follows:(1) To take an overview of four global navigation satellite systems:GPS, GLONASS, Galileo system and BDS, to contrast among four global navigation satellite systems similarities and differences in the frequency, the signal and the construction. To introduce the error sources in the positioning process and show the specific methods to eliminate the ionospheric errors, tropospheric errors, satellite clock bias, receiver clock bias and multi-path effects errors in this article.(2) To show the time systems and coordinate systems of global navigation satellite, point out the main problems that must be solved in the multi-mode GNSS positioning process are time unity and space unity. To deduce the GNSS positioning multi-mode principles and observing mathematical model, according to the principles of GPS single point positioning and different types of satellite (GEO, MEO, IGSO) position calculation methods, and then derive a multi-mode GNSS differential positioning model on that basis.(3) According to the data provided by the BDS&GPS regional trial network, to calculate the coordinates of the points, Geometric Dilution of Precision (GDOP) with the GNSS positioning model algorithm, to contrast the positioning accuracy of different navigation satellite systems (BDS GPS and BDS&GPS) under the Pseudorange point positioning and differential positioning, comparatively analyze merits and demerits of the BDS performance, and get some useful conclusions.(4) To introduce RAIM basic concepts, cluster analysis ideas and correlation distance ideas, then, based on the ideas, to improve RAIM algorithm and demonstrate the actual data as support. (5) To make the above research implemented into program designs on C++development platform, in which some modules can be good embedded in the BDS/GPS real-time communication system. As a result, real-time location solution can be achieved.