Research On Matrix Transformation Algorithm For Magnetic Gradient Target Location

The distribution of the geomagnetic field is affected by the magnetic field generated by the magnetic target,and the magnetic field generated by the magnetic target is called the magnetic anomaly field.The current target positioning technology is to measure the magnetic anomaly field of the target,and calculate the magnetic moment information and position information of the target through algorithm deduction.In recent years,the use of geomagnetic fields to locate targets has developed rapidly and has been widely used in many fields,such as archaeological exploration in archaeological research,shipwreck exploration,and detection of unexploded ordnance.The magnetic anomaly field localization technology in the geomagnetic field mainly includes the geomagnetic total field measurement and the geomagnetic gradient tensor measurement.Among them,geomagnetic gradient tensor measurement belongs to vector measurement,mainly using vector magnetometer such as fluxgate.Compared with total field optical pump magnetometer,fluxgate vector magnetometer has lower sensitivity and strict posture placement.Factors such as ambient temperature have large influences and measurement accuracy is low.Therefore,based on the proposed geomagnetic field measurement method,this paper proposes a matrix transformation algorithm that uses magnetic gradient to locate the magnetic target.The solution has high precision and fast calculation speed,and can provide reference for high-precision long-distance rapid positioning of magnetic targets.A scalar magnetometer is required to measure the total geomagnetic field.The commonly used scalar magnetometers are proton magnetometers and optically pump magnetometers.The proton magnetometer has a low sampling rate,generally does not perform dynamic measurement,and has a slightly lower sensitivity and large power consumption.At present,proton magnetometers are mainly used in seismic fields such as seismic networks and space magnetic fields.The optically pump magnetometer has a high sampling rate and high sensitivity,and is suitable for dynamic measurement,and is suitable for measuring moving objects such as aviation and navigation.It is the reason why we chose the high-precision optically pumped magnetometer for this topic.Since the target magnetic moment and position involve a large number of unknowns,it is necessary to establish a magnetometer array by using a plurality of total field magnetometers when measuring the magnetic field.Using the principle of magnetic dipoles,a set of measurement array equations is constructed.The geomagnetic field is the physical quantity that changes with time and space.In order to eliminate the influence of this change factor on the target location,the magnetic gradient is used to construct the fitness function of the array equations.This function belongs to the high-order multi-parameter function and cannot be solved.Solution,and the general numerical solution process is more complicated.It takes a long time,has many false values,and is easy to diverge.Therefore,reducing the number of unknown parameters solved can effectively improve the calculation convergence speed and positioning accuracy.The optimization algorithm can be used to solve the fitness function.The optimization algorithm mainly includes particle swarm optimization algorithm,genetic algorithm and simulated annealing algorithm.Among them,the particle swarm algorithm has fast calculation speed,high calculation precision,less adjustable parameters and convenient operation.Select the particle swarm optimization algorithm to locate the target.Using matrix transformation,the six unknown parameters needed to solve the target location are reduced to three.The position information parameters are used to represent the magnetic moment information parameters,and the fitness function of the target location is constructed.The particle swarm optimization algorithm is used to solve the problem in MATLAB.Simulation was performed on the simulation platform.Experiments on target location along the Songhua River were carried out,and a scalar magnetic sensor array was constructed.The magnetic field partially changed in the geomagnetic field was eliminated by the double gradient algorithm.The comparison between the experimental results and the simulation data showed that the magnetic transformation was performed by this matrix transformation algorithm.Target positioning is feasible.