Auxiliary Navigation Method Based On Underwater Terrain Image Registration

At present, the navigation systems of the underwater diving apparatus uses to operate is mostly core inertial navigation task. However, with the accumulation of time, the positioning error of inertial navigation still exists. Therefore, in the long voyage, the information provided by the inertial navigation will be inaccurate, affecting the efficiency. The use of underwater aided navigation technology can effectively correct the navigation error of inertial navigation.And the terrain aided navigation also has the advantage of high positioning accuracy, strong limitation, concealment and high degree of autonomy, etc. With the low price, the improvement of the underwater equipment performance, and the effective correction of inertial navigation error, the underwater aided navigation system which use of the information of terrain elevation can greatly enhance the engineering applicability of water diving device.Therefore, this paper will use the water diving apparatus with multi-beam sounding system to measure the underwater terrain elevation data, convert them to the sonar image,based on image processing algorithm, and study a set of auxiliary navigation method based on the underwater terrain.This paper will firstly deal with the interpolation processing data provided by the multi-beam sonar system, convert it to sonar gray image, and extract texture feature extraction of underwater terrain and moment invariant features. This paper will also analyze the influence on characteristic parameter values under different conditions, selecting the characteristics of strong anti-jamming capability parameters constitute a feature vector.Secondly,this paper will analyze the suitability problem in terms of different kinds of underwater terrain, put forward the judgment method on the basis of the suitability of underwater terrain image characteristic parameter, and compare with the traditional fitment judgment conditions, and discuss the advantages and disadvantages of two methods, and then summarize the new underwater terrain suitability judgment conditions.Moreover, in order to ensure the accuracy of water diving device navigation and positioning,improve the efficiency of navigation, this paper, based on the underwater topography image grey coarse matching combination based on underwater terrain image feature vector way of precise matching,and comparative analysis with traditional terrain contour matching navigation system, expounds the advantages of image matching based on underwater terrain. And give a comparative analysis of maximum cross-correlation method to calculate heading angle, this paper puts forward the multiple sub-graph coordinate method, to reduce the computing time, and further improve the location accuracy.Finally, for the convenience of the better and effective use of algorithm, this paper designs the interface of underwater terrain auxiliary navigation, and discuss function and operation methods of interface module.