Study On Tightly Coupled Navigation Algorithm For SINS Assisted GPS Satellite Selection

The tight coupling between Strap down Inertial Navigation System(SINS)and Global Positioning System(GPS)can improve the positioning accuracy of the navigation system.Among them,the method of selecting stars is a key factor in determining the efficiency of tightly coupled fusion.However,current star selection methods have problems with low star selection efficiency and high computational complexity.Therefore,this article focuses on the star selection problem of SINS/GPS tightly coupled navigation algorithm and explores the method of SINS assisted GPS fast star selection.On this basis,this article designs an efficient SINS/GPS tightly coupled navigation algorithm,and verifies its effectiveness through simulation experiments.Firstly,the research status of SINS,GPS,SINS/GPS integrated navigation systems and star selection algorithms was introduced.The working principles of SINS and GPS were elaborated,the SINS navigation algorithm was derived,the system errors of SINS and GPS were analyzed,and two different SINS/GPS combination methods were compared.Secondly,the SINS assisted GPS fast star selection method was analyzed,and an improved SINS/GPS tightly coupled star selection algorithm was proposed.The algorithm detects the pseudo range outlier of visible satellites and removes them,selects the satellite with the largest altitude angle as the zenith satellite,randomly traverses the combination from the remaining visible satellites,and selects three satellites to form a positioning satellite combination with the zenith satellite.Calculate the Geometric Dilution of Precision(GDOP)value of the satellite combination,and select the satellite combination with the smallest GDOP value as the optimal satellite combination.Through MATLAB simulation,it has been proven that this algorithm can effectively improve the efficiency of star selection.Once again,a SINS/GPS tightly coupled navigation algorithm was designed.A mathematical model of SINS/GPS tightly coupled navigation algorithm has been established,which uses a Kalman filter to achieve SINS/GPS data fusion and uses a closed-loop feedback correction method to correct the errors of SINS and GPS.Finally,MATLAB was used to simulate and compare the SINS/GPS loosely coupled navigation algorithm with the SINS/GPS tightly coupled navigation algorithm.The results show that compared to the SINS/GPS loosely coupled navigation algorithm,the SINS/GPS tightly coupled navigation algorithm has a significant improvement in stability and navigation accuracy.