| Geomagnetic matching navigation as an advanced navigation method,with the advantages of all-weather,all-region,no radiation,strong concealment and error does not accumulate with time,has a good development prospect and has received extensive attention in the world.At present,there are three main factors restricting the development and application of geomagnetic matching navigation technology:first,the geomagnetic survey error is large in the dynamic environment,second,it is difficult to establish a high-precision geomagnetic database,and third,compared with the positioning accuracy of satellite navigation,the positioning accuracy of the current geomagnetic matching navigation algorithm is not high.Among them,the establishment of a high-precision geomagnetic database is the key to the realization of geomagnetic matching navigation,and its accuracy will directly affect the selection of geomagnetic matching navigation algorithm and the accuracy of matching positioning.The purpose of this paper is to study and analyze the establishment method of geomagnetic database and geomagnetic matching navigation algorithm,put forward the improved geomagnetic database establishment method and the corresponding navigation and positioning algorithm,and carry on the experimental analysis based on IGRF-13 model data and measured aeromagnetic data respectively.The main work of this paper is as follows:（1）An improved polynomial model database building algorithm is proposed to reduce the storage memory of the geomagnetic database.Through test and analysis,the geomagnetic data with a sampling interval of 7 meters are stored in the 200KM*200KM range,and the geomagnetic database established is more than 10GB,but the improved polynomial model database algorithm is to build a model with geomagnetic characteristics as independent variables and geodetic coordinates as dependent variables,which builds the model database for the same area,and the memory occupied is not more than 100MB.（2）A navigation and positioning algorithm based on hierarchical submap is proposed,which reduces the matching time of geomagnetic matching navigation and positioning and ensures the real-time performance of geomagnetic matching navigation and positioning.The algorithm divides a large area into several small areas,and then uses the step-by-step retrieval and location method to improve the location efficiency.The results show that it takes an average of 1.106 seconds to match and locate a point using MAD algorithm,but only 0.002seconds for this algorithm.（3）The influence of the combination of characteristic parameters in different geomagnetic directions on the positioning accuracy of geomagnetic matching navigation is studied.The geomagnetic matching navigation and positioning is carried out by using the combination of different geomagnetic directional features and directional features,and there are 16 forms.The test results show that that the positioning accuracy of matching navigation using one geomagnetic directional feature is the worst.The combination of geomagnetic features Y and Z has the highest positioning accuracy for geomagnetic matching navigation.（4）Combined with the improved polynomial model building algorithm and hierarchical subgraph navigation and positioning algorithm,the edge error is greatly reduced and the navigation and positioning accuracy is improved.Experimental display based on IGRF-13model data show that the positioning accuracy of the geomagnetic database established by the algorithm in the range of 200KM*200KM is 10-6.°in longitude and latitude,which is higher than that of the traditional geomagnetic matching navigation algorithm MAD. |
