Research On The Method Of Underwater Terrain Matching And Location Based On Sonar Image

When autonomous underwater vehicles(AUV)conduct continuous and long-term underwater navigation operations,high-precision underwater navigation information is required to determine their own positions in real time,but AUV equipped with inertial navigation systems(INS)perform long-distance and long-term underwater operations.During sailing,its positioning error will accumulate over time,so an auxiliary positioning method is needed to correct its positioning error.In this paper,based on the underwater terrain elevation data collected by the multi-beam bathymetry system in the underwater data acquisition system,and on the background that the positioning error of the INS will accumulate over time during navigation and positioning,the underwater terrain for auxiliary correction of the accumulated error is studied.Matching positioning technology.The data based on this paper are the underwater terrain data measured by the multi-beam bathymetry system and the images formed by it.The study selects and constructs appropriate feature parameters by analyzing the terrain features,and combines the corresponding feature evaluation algorithms to realize the underwater terrain.The analysis of the degree of adaptation and the research on the matching and positioning method of the underwater terrain area.The research in this paper can provide a reliable method for route planning and navigation error correction during AUV navigation operations,and expand the applicable environment of underwater terrain matching positioning method.This paper firstly analyzes the adaptability of underwater topographic images,defines the digital map in the underwater map database as the reference topographic map,and selects the feature vector with the topographic texture as the main feature according to the characteristics of the underwater terrain as the evaluation basis.The fuzziness evaluation algorithm processes the feature vectors and sorts the sub-regions of the reference topographic map to obtain the adaptability sequence of the sub-regions of the reference topographic map.Then,based on the results of the adaptability analysis,some sub-regions of the reference topographic map are selected as the reference topographic map for terrain matching research.Then,the traditional image features are introduced.Based on the characteristics of the terrain itself and the standard of adaptability analysis,some image features are selected to form combined feature vectors and spatial relationship features as the basis for registration.The spatial relationship feature selects the Hu invariant moment as the matching basis,and uses the cosine similarity as the judgment algorithm to preliminarily screen the sub-regions of the reference topographic map.decision to achieve accurate matching and positioning of the AUV.In addition,this paper also introduces and studies the signal processing method of underwater terrain matching,and selects the wavelet moment feature based on wavelet transform and invariant moment theory to explore the applicability of the algorithm in underwater terrain matching.