The Method Research And Software Realization Of GPS/BDS Combination Baseline Solution

Beidou satellite navigation is an independent development satellite navigation and positioning system with independent intellectual property rights,which is the third satellite navigation system that can position after the U.S. GPS, the Russian GLONASS in the world.Recentely,in the high precision positioning,baseline solution occupies the largest workload of GNSS static measurement data processing.As the base of network adjustment,the quality of baseline solution has a direct impact on the positiong accuracy and reliability of the GNSS network. Because of the limitation of the using-permissions of independent satellite navigation system and observing conditions, the accuracy, security, availability and reliability of providing satellite positioning sometimes can not be fully guaranteed.However,the combination of GPS and BDS can solve this problem,by increasing the numble of visible satellites,reducing the dilution factor of accuracy and consisting a better satellite structure.This provide the possibility of improving positioning accuracy.Recently, research on high precision baseline resolution of GPS/BDS combination is limited to the stage of theoretical discussion.This paper firstly solves the problem of satellite coordinates calculation according to the broadcast ephemeris of GPS and BDS system.And then introduces the basic theory of GPS/BDS system integration relative positioning in detail,because of the difference between GPS and BDS in time reference and spatial reference,needing to realize the unification of time system and coordinate system,the paper blends the BDS space-time basis into GPS basis.On the premise of GPS/BDS unification,studies the function model,stochastic model and error analysis and correction methods of GPS/BDS system integration relative positioning.Then analysis the cycle slip detection and GPS/BDS combination double difference ambiguity in detail.It takes advantage of Melbourne-Wubbena combination and Ionosphere Residual Error Method to detect cycle slip,uses Kalman filter to obtain the real solutions of ambiguity and utilizes LAMBDA to fix ambiguity,and then analysis the LAMBDA algorithm in detail. Finally,it develops a software for baseline solution of GPS/BDS combination system,and verifies the correctness practicability of the software through the example.