Research On Key Technology Of Geomagnetic Assisted Navigation

Geomagnetic navigation technology has always been a hot topic in the field of navigation,as well as an important research direction.While geomagnetic navigation has the advantages of passive positioning,all-weather observability and low cost,it also has the disadvantage of not being able to provide long-term positioning information.Therefore,this technology usually plays the role of an auxiliary navigation,combined with other navigation systems,in order to achieve long-endurance,high-precision navigation targets.The thesis discusses the basic theoretical knowledge of the geomagnetic field,geomagnetic detection and data processing techniques,geomagnetic datum map construction techniques,geomagnetic field spatial extension techniques,geomagnetic suitability analysis and geomagnetic matching algorithms,with the aim of forming a combined navigation system with the aid of geomagnetic navigation to correct the accumulated errors of inertial navigation systems.Among them,the focus is on the geomagnetic-aided navigation algorithm,and a geomagnetic-aided navigation algorithm with improved chaotic ant colony is proposed.The main work is as follows.Firstly,the basic concepts of the geomagnetic field are introduced,specifically including the composition of the geomagnetic field,the geomagnetic elements and their distribution characteristics and the total intensity magnetic anomaly are elaborated,providing theoretical support for the use of the geomagnetic field for position location.The working principle of geomagnetic-aided navigation is analysed and the key technologies involved in geomagnetic navigation are discussed and investigated.Then,a theoretical study is conducted to investigate the changes in the suitability of the geomagnetic map before and after its downward extension,and a comprehensive weighting method is proposed to evaluate the suitability of the geomagnetic map.The evaluation method uses factor analysis to extract the main characteristic parameters as common factors,and the weights obtained by the entropy method are linearly combined with the weights obtained by the factor analysis method to assign weights to the common factors,thus achieving a comprehensive evaluation effect.Finally,the evaluation method proposed in the thesis is used to evaluate the suitability of the geomagnetic map before and after downward extension,and the accuracy of the evaluation results is verified through experiments.Finally,a geomagnetic matching navigation algorithm with improved chaotic ant colony is proposed.The algorithm uses the Mean Hausdorff Distance(MHD)as the metric function between the trajectory to be matched and the measured trajectory,improves the probability transfer formula and pheromone representation of the traditional ant colony algorithm,and embeds the chaos optimisation algorithm into the traditional ant colony algorithm.The problem that the Magnetic Contour Matching(MAGCOM)algorithm relies too much on the inertial guidance system for matching navigation and has a weak noise immunity and low matching accuracy is effectively solved.The paper has 30 figures,17 tables and 70 references.