Research On Gps/Ins Direct Fusion Positioning Algorithm Based On UKF Considering Lever Arm

Global Positioning System(GPS)can provide accurate,all-weather satellite positioning and global navigation information services to users worldwide.However,due to the influence of external conditions,when the signal is lost,it is easy to cause a decrease in positioning accuracy.Inertial Navigation System(INS)is an independent,non-interference three-dimensional trajectory projection navigation system,which has the characteristics of high short-term accuracy and rapid accumulation of errors over time.The combination of GPS and INS can make up for the shortcomings between the two and bring out the advantages of navigation.With the increase of people's demand for navigation,the field of integrated navigation has become a popular research point.This paper will start the research based on GPS/INS integrated navigation,and the main research content and innovation points include:(1)First,the current status of research on single navigation and integrated navigation is analyzed.Second,for the problem that single navigation is difficult to cope with the demand of high accuracy,high real-time and high reliability,the GPS/INS integrated navigation is used.Third,the basic principle of integrated GPS/INS navigation is derived,and in order to verify part of the inertial navigation principle and analyze the error accumulation characteristics of static inertial navigation,a stationary simulation experiment of inertial navigation is conducted based on MATLAB.(2)The principle of lever arm effect between GPS and INS is investigated for the influence of lever arm effect on positioning accuracy in high precision navigation.To address the problem that the lever arm is difficult to measure in practical applications,the lever arm parameters are included as state vecotr in the Kalman filter for transmission and estimation to reduce the impact of the lever arm effect on the integrated navigation.Then,a direct filtering method model considering the lever arm is established.(3)The application of the UKF filtering algorithm considering the lever arm effect to the GPS/INS direct method is investigated.Firstly,the UKF algorithm is applied to the direct method for the nonlinearity problem of direct method filtering.Secondly,to address the problem of the impact of the lever arm effect on positioning accuracy in high-precision navigation,the UKF algorithm considering the lever arm effect is proposed for the GPS/INS direct filtering method.(4)Based on the simulation trajectory designed at MATLAB,three sets of simulation experiments were conducted to verify and analyze the effectiveness of the algorithm.By comparing the simulation results,it is concluded that compared with the traditional Kalman indirect filtering method and the UKF direct filtering method,the UKF direct method filtering algorithm considering the lever arm proposed in this paper is able to estimate the lever arm between the IMU and the GPS receiver accurately and in real time on the one hand,and to improve the accuracy of the integrated navigation system on the other hand.(5)A hardware platform of GPS and INS integrated navigation system composed of ten-dimensional MEMS sensors was established and static tests were conducted.The test results of the navigation algorithm verify the correctness of the integrated navigation theory derived in the paper.It lays a good foundation for further hardware experiments of GPS/INS integrated system in the future.