Research On Self-correcting Geomagnetic Tracing Technology Based On Multi Feature Fusion

Geomagnetic tracing is a navigation method that uses the geomagnetic feature quantity for matching positioning and realizes the autonomous tracing operation of the carrier in the low-altitude region.The existing geomagnetic matching methods usually only perform point matching for the total geomagnetic field or its gradient,and because of its single matching feature quantity,the matching accuracy is low in the region where the geomagnetic features are not obvious,and the positioning accuracy is limited.This paper proposes a self-correcting tracing algorithm that fuses geomagnetic feature quantities,Jetlink inertial navigation data,and GPS data via traceless Kalman filtering data to improve anti-magnetic interference capability.Moreover,the tracing system is capable of maintaining stable operation even in the event of GPS signal loss for a certain period of time.The paper’s main work includes this.(1)Based on the geomagnetic field theory,the differences of different geomagnetic eigenvolumes in the geomagnetic matching algorithm are analyzed,and four different geomagnetic eigenvolumes are selected for matching.Based on the traditional nearestneighbor contour iterative algorithm,the multi-geomagnetic feature fusion nearest-neighbor contour iterative algorithm(MUF-ICCP)is designed,and the localization results are obtained by weighted average based on the entropy values of the geomagnetic information of the magnetograms involved in the matching.The algorithm is able to reduce the accuracy degradation caused by running trajectories parallel to the geomagnetic map contours when single geomagnetic eigenvolume is matched.The simulation results show that its positioning accuracy is better than 3.5m.(2)The multi-feature fusion self-correcting geomagnetic tracing algorithm(MUFUCGEMTA)is formed by fusing GPS,Jetlink inertial navigation and MUF-ICCP algorithms through traceless Kalman filtering.The algorithm is able to correct the error with Jetlink inertial guidance and GPS data when the geomagnetic matching is subject to strong magnetic interference,and correct the accumulated error of inertial devices with MUFICCP algorithm when GPS information is lost in a short period of time to achieve the complementary advantages among algorithms.(3)A three-dimensional square Helmholtz coil geomagnetic field simulation device is designed and indoor simulation experiments of geomagnetic environment are carried out to verify the feasibility of MUF-ICCP algorithm.Testing the MUFUC-GEMTA algorithm’s performance,an experiment was devised to assess its anti-magnetic interference capability and system dependability when GPS signal is lost in a brief span of time,utilizing a combined navigation device for outdoor vehicle navigation.The experiments show that MUFUC-GEMTA can guarantee an effective positioning accuracy of 6.9m during the smooth phase,and can still meet the system positioning error of better than 30 m when subject to strong magnetic interference of up to 230 n T and the loss of GPS signal for less than 6 min,which meets the pre-designed requirements.In summary,the designed MUFUC-GEMTA algorithm has better positioning accuracy and anti-interference capability than the existing geomagnetic positioning methods.