Research On GPS Carrier Phase/INS Tightly Coupled Navigation Algorithm

When the observation environment is good,GNSS dynamic positioning can obtain centimeter level positioning accuracy.But in the complex environment such as the city,it is easy to appear the phenomenon of signal attenuation,occlusion and interruption,which can not guarantee its positioning accuracy,continuity and reliability.GNSS/INS integrated navigation technology can improve the positioning accuracy and continuity of GNSS,so it is widely used.In the complex environment such as city,the traditional loosely coupled is easy to be limited by the number of satellites,while the tightly coupled based on pseudorange is limited by the precision of pseudorange,which can not meet the needs of higher precision applications.Taking GPS system as the research object,this thesis focuses on the research of GPS carrier phase/INS tightly coupled navigation algorithm,aiming to improve the positioning accuracy,continuity and reliability of GPS dynamic positioning.The main research contents and achievements of this thesis are as follows:(1)A combination method of cycle slip detection and repair is proposed,which uses the ionospheric residual method and the MW combination method to detect cycle slip,then uses the pseudorange and phase comparison method and the ionospheric residual method to repair on the basis,and finally checks whether the repair is successful through the MW wide lane ambiguity.Experimental results show that the positioning accuracy and the fixed rate of ambiguity of the method are basically consistent with the results of single epoch solution,and can be used for dynamic positioning solution.(2)An ambiguity resolution strategy of combining the single frequency and wide lane observations is proposed.The experiment shows that the solution strategy can not only improve the fixed success rate of GPS ambiguity,but also obtain higher dynamic positioning accuracy.(3)The system equations and measurement equations of the GPS/INS tightly coupled navigation are deduced,and the estimation method and parameter elimination strategy of adding GPS ambiguity parameters to the GPS/INS equation of state are proposed.The experiment shows that compared with GPS dynamic positioning,the fixed rate of ambiguity of GPS/INS tightly coupled is higher,and the positioning accuracy and continuity are significantly improved.(4)Based on GPS dynamic positioning algorithm and GPS/INS tightly coupled algorithm,the prototype of GPS/INS tightly coupled software is designed and developed,and the performance of the software is analyzed through two groups of experiments.Experiments are carried out with GPS data and tightly coupled data of different environments,receivers and INS grades,which not only verify the effectiveness of GPS dynamic positioning and tightly coupled algorithm,but also verify the availability of software.