Research On The Geomagnetic Map Matching Method Of AUV

Geomagnetism Aided Navigation (GAN) is an integrated navigation system whose core is the inertial navigation.It has good performance in hiding itself and can be used in a broad field.It has simple structure but reliable.More than this,it is precise and costs less.For these merits above,it meets the future demand of AUV and will be widely used in it.As one of the important components of the GAN,the geomagnetic map matching method(GMMM) is an important factor to effect the precision of the system positioning.The main research of this thesis is GMMM.First,by analyzing the expression of the geomagnetism field,the types of the geomagnetic matching system is summed up.Two matching systems which are geomagnetic model matching and geomagnetic map matching are designed.It compares the two system and draw a conclusion of their advantages and disadvantages.In order to make the GMMM realized accurately,the Kringing method is introduced into the technology of reconstruction of the geomagnetic map.Results show that the Kriging method is of great practical value when applied to the reconstruction of geomagnetic map.Secondly, the geomagnetic map matching method which is based on correlative extremum is brought forward and the progress of the method is eixpatiated in detail.Three important aspects which are relatived to the method are researched in the thesis, including the comparing of two methods applied to choose the geomagnetic adapted district, the comparing of capability of the MAD and the COR and the correlative geomagnetism length is analized. The results of the simulatation indicates that the correct matching probability of the geomagnetic map matching method based on correlative extremum is not sure,and the method is more restricted by the planning of the sailing track and the realization of the method is difficult.In the end, the geomagnetic map matching method based on the isoline matching is proposed.The emphesis is the procedure of detrusion of the drawing of the isoline and the position determination of the closest contour point.Simulation successfully realizes the global optimization of the matching track.Compared with the geomagnetic map matching method which is based on correlative extremum ,the advantage of the geomagnetic map matching method based on the isoline matching is that the vehicle can move flexibly during the progress of the positioning.The method has not strict require on the adaptive ability of the geomagnetic map,which makes it more practical.