Study On Acoustic Resonance Landmine Detection Method Based On The Acoustic-vibration Characteristics Of Landmine

Due to the complexity of minefield environment and the diversity of landmine types,the effective detection of landmines has always been a worldwide problem,especially plastic landmines,which are difficult to be effectively detected by metal detector,the most commonly used mine detection tool,because of the small difference in electromagnetic characteristics between plastic landmines and soil environment.Since the 1990 s,when the United Nations Mine Action Service and other international humanitarian agencies jointly called for the development of effective mine-detection technologies,several methods based on different principles have emerged.Among them,the acoustic-to-seismic(A/S)landmine detection method based on the mechanical property of larger compliance of mines has shown good application potential in the detection of both metal and non-metal mines,but a lot of research work is still needed for developing the practical mine detection engineering system.In this thesis,the A/S coupling mechanism is systematically analyzed based on the acoustic theory and seismic theory,and the influence mechanism of soil environmental factors on detection signal characteristics is analyzed parametrically with the numerical method based on transfer function,which further enriches the theoretical system of acoustic mine detection.Three sets of acoustic mine detection experimental systems,a contact system,an acoustic-light system for studying the detected signal and an acoustic-light engineering studying system have been designed and built independently,and good experimental results have been achieved,which provides experimental basis and model reference for the development of acoustic mine detection engineering system.Meanwhile,this thesis also proposes an optimization design method for a new type of landmine detection prodder based on accelerometer,and on this basis,a design scheme of an intelligent landmine detection prodder is proposed,providing a reference scheme of multi-sensor fusion for solving the detection limitation of acoustic mine detection method in some specific minefield environments.The main work and innovation of this thesis are as follows:(1)The principle of A/S landmine detection is systematically analyzed based on acoustics and seismic wave theory.Based on the acoustic and seismic principles such as transmission and reflection,the A/S coupling mechanism of acoustic wave coupling into soil to form seismic wave is systematically analyzed.The slow p-wave generated in A/S coupling process mainly spread in the fluid phase medium of the soil,so it will reflect strongly at the mine due to the large impedance rate difference between the fluid phase composition of soil and mines,and stimulates the resonance behavior of landmine simultaneously,causing the obvious change of vibration characteristics of the corresponding soil surface,which can be detected and identified with highly sensitive vibration sensor.(2)The influence mechanism of soil environment in minefield on acoustic mine detection signal characteristics is studied based on numerical analysis method.The transfer function of acoustic landmine detection model is deduced,and the related parameters were measured experimentaly.On this basis,the influence mechanism of soil environmental factors such as mechanical properties and buried depth on the measured signal characteristics is studied parametrically,providing a novel method for developing acoustic landmine detection engineering system,which further enriches the theory of acoustic landmine detection.(3)Three sets of acoustic mine detection experimental systems with different emphases were built to study acoustic vibration characteristics of landmineAccording to the development of the experimental conditions and the performance characteristics of the hardware device,a set of contact experimental system for verifying the feasibility of acoustic landmine detection,a set of noncontact acoustic-light landmine detection experimental system for studying the characteristics of measured signal,a set of acoustic-light engineering research experimental system based on a highly directional sound source have been built successively,promoting the engineering of acoustic landmine detection technology gradually.Moreover,the effectiveness of the parametric numerical analysis method based on the transfer function of the acoustic landmine detection model has been proved by the experimental results.(4)The optimization design method for a new type of lightning detector based on accelerometer is proposed A novel prodder for landmine detection based on accelerometer is the product of the fusion of acoustic mine detection technique and traditional mine prodder,which can make up for the limitation of acoustic mine detection method in some minefield environment which are very common in anti-landing operations.In this thesis,the influence mechanism of the component parameters of the prodder on the measured signal is studied,and on this basis,the optimization design method which can improve the performance of the prodder is proposed.Finally,the conceptual design of a practical intelligent prodder used for landmine detection is presented.