Study On New Geomagnetic Matching Algorithm

Geomagnetic Aided Navigation(GAN)is an important navigation technique by using geomagnetic information. It has good performance in hiding itself and can be used in many field broadly. It is considered as the ideal aided navigation system. Geomagnetic matching is one of the key techniques in GAN system. This thesis investigates some basic geomagnetic matching algorithms and analyses the practical application condition. Two new geomagnetic matching algorithms are put forward.The main contents and contributions include the following aspects.(1)The thesis introduces the physical characteristics of the geomagnetic field, the composition of the geomagnetic field and the basic geomagnetic field measure technology. The thesis builds up the frame of geomagnetic aided navigation system and introduces the geomagnetic matching principle. Two important geomagnetic matching algorithms-contour matching (CM) matching algorithm and iterative closest contour point (ICCP) matching algorithm-are introduced.(2)The iterative affine transform (IATM) geomagnetic matching algorithm is studied. The thesis introduces three basic matching models. The Simulated Annealing (SA) affine transform geomagnetic matching algorithm is investigated. The matching performance of three matching models is tested by geodesic geomagnetic data. Experiment result shows that the affine transform matching model performs better than both the parallelism transform matching model and the parallelism-circumrotation transform matching model. Matching time of the SA affine transform geomagnetic matching algorithm is too long. In order to deal with this problem, referring to the affine transform algorithm used in picture matching area, the iterative affine transform (IATM) geomagnetic matching algorithm is proposed.(3) In the practical application condition, the transform between the INS path and the real path is extremely complex. The above fixed matching model can't describe the matching problem well and truly. Iterative recursion matching algorithm is proposed. The process of the algorithm, electing method of the matching point searching area, electing method of the pending matching paths and the matching strategy are studied. Using the geodesic geomagnetic data, the iterative recursion matching algorithm is tested. The robustness and the antinoise property are analyzed.