Research Of Real Time Orientation Determination Technology Of BDS/GPS Dual System Based On Single Epoch

This paper focus on the fields of orientation determination of BDSsingle system and BDS/GPS dual system.The basic thought of Satelliteorientation determination was firstly raised in1970s. This technology,based on the satellite carrier phase signal interference measuring principle,is a method to determine orientation of the geometric vector of two pointsat a specified coordinate system. Compared with inertial navigation system,satellite navigation have the strength of all days working, no timeaccumulated error, low cost, and wide range of application. BDS is aGlobal Navigation Satellite System developed by our countryindependently. Till2012, it has already covered the whole Asia Pacificregion. While the orientation and positioning research of BDS is still in itsinfancy.To strengthen the study of BDS is of very important significanceno matter in academic field or national defense strategy.In the severe environment especially within the block of high buildingor bridge, it’s hard for a single system to track enough satellites tocomplete the orientation determination. BDS and GPS compositeorientation determination can improve the success rate in this condition.Due to the differences between BDS and GPS system, before theorientation determination process, it’s necessary to unify time, coordinatesystem, as well as the carrier frequency. This paper discusses thecompatibility of the two systems, analyses the error brought by thedifferences, and put forward the corresponding compensation solution.In the part of directional calculating, this paper is based on the principle of satellite carrier phase double difference measurements. Weused the least-square ambiguity search algorithm and established abaseline constraint in order to reduce the dimension of calculation. In thestep of ambiguity estimation and confirmation, the initial geometriccondition was added to speed up the calculations. Single epoch algorithmwas used so as to evade the whole carrier phase cycle jump problem,greatly shorten the initialization time. Lots of experiments were takenunder the BDS single system and BDS/GPS dual system. The experimentalresults show that by using this algorithm BDS single system orientedmodel can achieve very high success rate and precision. The success rateand precision of BDS/GPS dual system under the good environment isslightly lower than that of single system, but the dual system can solveproblem in severe condition where single system cannot figure out theorientation.