Research On Tensor Magnetic Detector Based On Zero Magnetic Environment

Magnetic anomaly detection has received more and more attention and has been widely used in many fields such as medical research,geophysics,and military engineering.As magnetic anomaly detection becomes more widely used,how to improve the detection performance of magnetic detectors becomes an urgent need.The tensor magnetic detector has the advantages of not being interfered by its own attitude and being able to overcome the influence of the geomagnetic field,and is currently a research hotspot.The analysis of magnetic detection methods and the calibration of tensor gradiometers are two important aspects of improving the detection performance of tensor magnetic detectors,aiming at the problems existing in the traditional analysis of magnetic detection methods and the traditional calibration methods of tensor gradiometers,the main research work carried out in this paper is as follows:Firstly,a multi-factor magnetic detection model is established,which lays a theoretical foundation for the objective and comprehensive analysis of the variation of the detection performance of the tensor magnetic detector under the multi-factor synergy.Aiming at the problem that the traditional magnetic detection model ignores the attitude and direction of the magnetic target,a "direction-attitude" spherical model is established.Aiming at the problem that the traditional magnetic detection model is not complete enough,nine influencing factors such as magnetic moment and detection distance are introduced,and a multi-factor magnetic detection model is established.Secondly,a new calibration method based on magnetic shielding chamber and threeaxis coil is proposed,which solves the problem that the calibration accuracy of the traditional scalar calibration method is limited by the non-magnetic turret and the geomagnetic field,and further improves the multi-factor magnetic detection model.The results of magnetic detection simulation show that the RMSE of the new calibration method is reduced by 44.60% compared with the traditional scalar calibration method,which proves that the new calibration method can further improve the calibration accuracy of the tensor gradiometer.Thirdly,based on the multi-factor magnetic detection model,the magnetic detection method is analyzed and calculated.The limitations of the traditional analysis of magnetic detection methods are proved by magnetic detection simulation.The calculation method of blind zone distribution law of magnetic detection method is proposed,and the blind zone distribution law of NARA method and Lv-STAR method is calculated.The variation of detection performance of NARA method and Lv-STAR method under multi-factor synergy is analyzed,and the detection range,the main factors affecting detection performance and the method for improving detection performance of two magnetic detection methods under different working conditions are obtained.And proved that the proposed new calibration method of tensor gradiometer can greatly improve the detection performance.Finally,the experimental platform of calibration and magnetic detection was built,and the accuracy and correctness of the new calibration method and multi-factor magnetic detection model were verified.After the tensor gradiometer is calibrated,the RMSE of the detection result is reduced by 69.11%,which proves the feasibility and effectiveness of the new calibration method.The actual magnetic detection is simulated based on the multi-factor magnetic detection model.The error percentage of the experimental results and the simulated experimental results no more than 10.16%,which proves the accuracy of the multi-factor magnetic detection model.the calculation results of the NARA method blind zone are consistent with the experimental results,which proves the correctness of the multi-factor magnetic detection model.