Research On Underwater Target Positioning Based On Magnetic Anomaly Detection

Naval military defense has extensive and profound influence in various countries.As the marine environment is complex and the situation is changeable,effective detection and early warning of non-cooperative targets under the sea has become the focus of research in various countries.The global technological revolution has produced breakthrough technological achievements like nuclear submarines.These technological achievements have also made effective detection of underwater targets gradually become one of the navy’s core tasks.Magnetic field signals are one of the most important physical field signals for underwater targets.They have the advantages of strong water penetration and less susceptibility to interference from the marine environment.Magnetic anomaly technology is used as a way to detect and analyze the magnetic characteristics of the target caused by magnetic anomalies.,And then real-time positioning of the target technology.Magnetic anomaly technology is an ideal way to realize real-time,continuous,concealed and precise positioning of underwater targets.Aiming at the problem of enabling surface ships to locate underwater targets more accurately,this paper proposes a method of using magnetic anomaly technology to locate targets based on magnetic moment attitude correction.First,the paper analyzes the mechanism of magnetic anomalies,and introduces the definition and formula of the magnetic gradient tensor and its invariants.After that,the typical magnetic field model was analyzed and investigated,and the differences of different models used in the analysis of the same target were compared.The key analysis of the magnetic dipole model is carried out,and it is verified that the concise magnetic dipole model is feasible in this scenario.This article explores a target location recognition method based on the geometric invariants of the magnetic gradient tensor,which uses the vector space relationship to separate the target location process from the recognition process and reduce the correlation between the positioning accuracy and the target recognition accuracy.This paper also studies the calculation method of magnetic moment,which is an important characteristic of magnetic targets,and proposes a magnetic moment calculation method based on magnetic gradient tensor and L-M optimization.Finally,combining the above two studies,try to apply the properties of magnetic moment invariance to the field of underwater target positioning of surface ships,and use the target magnetic moment invariance to correct the attitude uncertainty of the sea surface carrier.The new method enables the surface carrier to locate underwater targets with higher accuracy and better inversion effects when operating at sea.In addition,this paper builds a magnetic gradient tensor measurement system,analyzes the error source of the magnetic gradient tensor measurement system,and optimizes its calibration.Afterwards,the actual measurement experiment was carried out,the magnetic sensor array was used to detect and invert the position of the magnetic target,and the comparison and analysis with the actual position parameters were carried out to verify the feasibility of the proposed optimization method.