Positioning Method Of Magnetic Beacon System Based On Weak Magnetic Signal

The wide application of GPS and INS has promoted the rapid development of navigation and positioning technology in the context of open vision.The research of navigation and positioning technology in complex environment is attracting more and more attention,such as indoor or underground environment.In these environments,concrete is filled with rock and other materials will hinder and distort the transmission of high-frequency signals,which makes most of the positioning technology unable to play a role.The magnetic beacon positioning system has the characteristics of strong penetration,no multipath effect and non linear distance,which makes the magnetic beacon positioning technology have great potential in complex environment.However,it still has some challenges,including the limited coverage of magnetic field and the problems with fuzzy solutions.In order to solve these problems,this paper studies the magnetic field of low frequency magnetic beacon in detail,A new magnetic beacon positioning technology based on multi-sensor is proposed.In order to solve the problem of limited magnetic field coverage,the structure of magnetic beacon mainly includes two kinds of solenoid and permanent magnet.The magnetic field distribution model of two kinds of magnetic beacons is studied respectively.The magnetic field distribution range of the magnetic beacon is expanded by optimizing the structure of magnetic beacon,and the ANSYS simulation software is used to verify.The traditional magnetic beacon positioning algorithm is suitable for processing the magnetic field signal with high signal-to-noise ratio.In order to extract and identify the magnetic signal with low SNR in the far range of magnetic signal scale,noise analysis is carried out for magnetic signal,The magnetic field signal is identified and extracted by using the advantages of low frequency high resolution and adaptive spectral line enhancement algorithm of harmonic wavelet,and the detection ability of weak magnetic signal is improved.In view of the influence of prior information on the positioning results in traditional single sensor positioning algorithm,a method of solving relative pitch angle by using phase difference and feature vector is proposed.A single magnetic beacon positioning algorithm based on multi sensors is designed.The relative distance and relative orientation of target position are calculated by using the stable relative pitch angle in the sensor and the position constraint solution of multiple sensors.In view of the problem of the misalignment between the sensor and the coordinate system of the magnetic beacon,the paper analyzes the three axis magnetic beacon positioning algorithm theoretically,and realizes the six degree of freedom positioning of the target position by calculating the power matrix of the magnetic field signal.This paper introduces the composition of the magnetic beacon positioning system,and verifies and analyzes the feasibility of the multi-sensor localization algorithm.The paper analyzes and studies the effect of the location results caused by the installation error of the magnetic beacon,and proposes the error compensation algorithm.The effectiveness of the error compensation algorithm is verified by experiments.The feasibility of the algorithm is verified by the simulation software.