Multi-sensor Network Based Penetrator Detection And Optimization

Currently, with seldom attention on the trajectory of a penetrator penetrated, the principle and the depth determination is the world focused on. The underground trajectory is important for the performance evaluation, the appearance and the location of the penetrator. The range test is an effective way for determining the penetrator trajectory, unlike the earth’s surface or air targets testing, the underground penetrator cannot be observed by means of visual, so appropriate passive observer array is very important for determining the penetrator trajectory.This thesis based on the fully understanding of research significance, current status, development trend and application value of earth penetrator, the frame work and principle of the detection system in static and motion models are introduced. With the discussion about the key algorithm and core technology in detection system, the methods used in multi-sensor network and network optimization were deeply analyzed. This thesis studied the detection and location of earth penetrator underground in two models, moving and stationary. In motion model, the geophone arrays at different location and different models are discussed, and improving the location accuracy of time difference system by increasing the time resolution. In static model, the method that networking detection by using gamma-ray was used in simulation experiments and the theory feasibility of the method was verified. The main research results achieved are as follows:Firstly, this thesis uses the orthogonal experiment to demonstrate the network optimization scheme in detail. In the determined scheme, this thesis does simulation experiments of the principle of the time difference network optimization and the detection of position in a two-dimensional coordinate. Determining that, under the rule of the biggest time resolution, the best disposal model is the prime column model. By the simulation of Monte Carlo in the three-dimensional coordinate system, the best formation of sensor network is determined under criterion of maximum time difference resolution when using transit-time location and detection. Three detection models, those are logarithmic spiral, Archimedes spiral and Hadamard matrix, were used respectively. Combining with the characteristics of engineering applications, Hardamard matrix model was determined as the best formation.Secondly, this paper discussed the special case that the equation of the system had no solution (i.e. contradictory equation), and proposed using the least squares method to solve the equation with no solution. Based on the above research, this paper detected and located the earth penetrator, discussed the impact of horizontal angle and position of detection point on system accuracy in two-dimensional coordination system. Then, the impact of best detector array model, horizontal angle and position of detection point on system accuracy was discussed in three-dimensional coordinate system. And we confirmed that this method is theoretically achieving the accuracy requirement of engineering.Last, system equation is obtained by network detection of gamma ray, and the formula of Cramer-Rao lower bound is deduced and solved. Meanwhile, such a detecting technology based on Cramer-Rao lower bound is analyzed and discussed which is also verified with the conclusion of numerical simulation to remedy the drawback of pure theoretical simulation.