Research On Identification And Location Method Of Target In Minefield

Minefield targets refer to mines,bullets,shells,grenades and other explosives in the minefield that used to be the front of the main battlefield.Their existence has seriously affected the normal life of the people living near the minefield.Minefields have been idle for a long time because of their danger.Most of them grow dense vegetation and have complex topographic structure,which brings great difficulty to the exploration and demining work.Combined with the actual system,taking the metal mine in the minefield target as the research object,this thesis studies some theoretical and technical problems in the methods of minefield target detection,recognition and positioning.The main research contents are as follows:(1)In view of the low efficiency of minefield target detection,this thesis proposes a method of minefield target multi-point synchronous detection,and designs a minefield target multi-point synchronous detection system,which realizes the synchronous acquisition of transmission signal,echo signal,envelope signal and root mean square data by each detection unit,so as to avoid the influence of temporal and spatial differences on the detection data.In order to solve the problems of high power consumption and high cost in high-frequency signal acquisition,a low sampling frequency synchronous acquisition method of UWB signal is proposed in this thesis,which realizes the acquisition of high-frequency signal with low power consumption and high efficiency.Finally,a spectrum refinement method for synchronous detection of minefield targets is proposed to achieve high frequency resolution in a wide frequency band,which lays a foundation for improving the accuracy of subsequent minefield target recognition.(2)In view of the fading phenomenon of pulse in the process of underground propagation and the eddy current effect when encountering metal,this thesis constructs the target echo model of shallow buried minefield,analyzes the refined spectrum characteristics of envelope signal based on the model,and puts forward the recognition method of minefield target fading characteristics based on high-frequency energy criterion,extreme spectral line symmetry criterion and interference factor criterion.Aiming at the refined spectrum of envelope signal,according to the formation reason of echo carrying minefield target information,this thesis deduces the calculation method of minefield target burial depth,and summarizes the multi-source information fusion minefield target recognition method based on synchronous detection.Finally,the feasibility of this method is verified by simulation and experiment.(3)According to the system characteristics and electromagnetic wave propagation characteristics,this thesis establishes the synchronous positioning model of non cooperative underground minefield target,and extracts the TOA characteristics of transmitted signal and echo signal.Combined with the azimuth clock provided by RTK,the two-dimensional coordinates of the minefield target are calculated by the triangular centroid method,and then the burial depth of the minefield target is calculated according to the geometric relationship of the synchronous positioning model,so as to obtain the three-dimensional coordinates of the minefield target.Combined with the synchronous detection method,the non cooperative synchronous positioning method of minefield target is summarized.Finally,the effectiveness of this method is verified by simulation and experiment.