Study On Error Mechanism And Matching Method In Geomagnetic Vector Navigation

Geomagnetic matching is the core technology of geomagnetic navigation.There are great limitations in the traditional geomagnetic matching method since the geomagnetic total information is used as the single function of matching feature information.In the case where the track is vertical,parallel to the geomagnetic contour lines,or there are multiple equivalence contours in the track,there may be an algorithm failure,poor matching accuracy or even mismatching.Compared to the geomagnetic total field,the geomagnetic vector field contains more abundant geomagnetic information.In the same area,even if the total magnetic field characteristics are not obvious,there always are lots of obvious geomagnetic vector characteristics.Therefore,geomagnetic vector information can be used as the geomagnetic field characteristic information for matching and positioning,which can realize higher precision geomagnetic vector matching navigation.However,the accuracy of geomagnetic vector measurement is far lower than that of geomagnetic total measurement both at home and abroad,and the measurement process is more complicated.So,the development and application of geomagnetic vector matching is greatly limited.In view of the above problems,this paper focuses on the geomagnetic vector navigation error mechanism and matching method research to analyze the sources of errors in the navigation system and their impact.As a result,the geomagnetic vector matching navigation strategy based on different situations,and a set of geomagnetic vector matching method with higher precision,faster speed and stronger robustness are established to provide theoretical basis for geomagnetic vector matching navigation and positioning.(1)The principle of geomagnetic vector navigation,geomagnetic vector elements and measurement methods are explained,and two basic geomagnetic vector matching algorithms for geomagnetic contour correlation matching(MAGCOM)and isoline nearest point iteration(ICCP)are introduced.The geomagnetic vector matching navigation error is analyzed in detail,and the error sources and their action mechanisms such as magnetic sensor,carrier interference,attitude angle and geomagnetic vector matching algorithm are simulated and numerically calculated.According to above all,the error weight distribution based on the coefficient of variation(CV)is proposed.And the navigation matching strategy for different situations is optimized as well.(2)According to the situation that the track error cannot be effectively calibrate by using general MAGCOM geomagnetic vector matching algorithm,when the reference track has a large heading difference.A vector correlation matching method based on heading self-adaption algorithm is proposed.The inertial navigation 3? error is used as radius and adjacent contours are used as grid nodes for the matching total contour search band to reduce the algorithm to traverse the data points.It improves the precision of the algorithm while reducing the computational complexity and provides navigation method support for the mobile carrier under high speed,variable speed and untypical track navigation.(3)According to the inefficient iterative step,and the huge number of selected points during general ICCP vector matching process,which cannnot meet the geomagnetic vector matching navigation requirement for a long-time trip.A geomagnetic vector matching algorithm based on total equivalent band and heading constraint is proposed.The selection of the constraints of contour bands,the determination of the trusted track under the heading constraints,and the optimal matching track criteria are introduced in detailed.The simulation results show that the influence caused by geomagnetic vector error can be effectively suppressed.Meanwhile,the matching efficiency is improved.As a result,the requirement of long-time trip for mobile carrier is met by using the geomagnetic vector navigation.