Design And Implementation Of Projectile Falling Point Localization System Based On Acoustic Time-Delay Measure Technology

The shooting range test is very important in the research of the cannon-ball. In order to verify the performance of cannon-ball, it is necessary to save information concerning the flying status in a"black box", When the cannon-ball falls to the ground, the analysis of relative characteristics of cannon-ball can be done only if the falling point of the"black box"and the"black box"is found .Traditionally, in the shooting range test, the position of cannon-ball is searched by men. In order to solve the problems resulting from artificially detection of explosion position,such as the no real-time character, the lower accuracy and without safety, a passive positioning system based on acoustic location principle is introduced. Relative to the active location, the passive location has the characteristics of fine concealment, excellent safety and lower cost.Acoustic sensor array technology and time-delay estimation are two key problems in the passive acoustic positioning system. The mathematical model of hexahydric cross acoustic sensor array and the efficient algorithm of the time delay estimation are studied based on the analysis of the present technology of target location at home and abroad. And the some factors affecting the positioning precision are also analyzed, the target location system consisting of the sound sensing, data processing and conversion are developed. The feasibility of the system is verified by experiment. The result shows that the positioning accuracy is decided by the following factors: estimated values of time-delay, distances among sensors, sound speed, pitching angle and azimuth.The main works of the dissertation are as follows:(1) After description of the principle and key technologies of the acoustic localization technology. The current status at home and abroad is summarized, and the development trend of the target acoustic localization technology is pointed out.(2) The physical characteristics and propagation disciplinarians in the air of the exploding wave at the falling point are introduced.(3) On the basis of the analysis of various acoustic localization methods, the mathematic model of hexahydric cross acoustic sensor array is built to analyze the time delay estimation and environmental error of passive acoustic localization. The relative factors affecting the orientation precision of the system are stressed and ways of improving the precision have been put forward.(4) The weak signal amplifying circuit,band-pass filter circuit,A / D converting circuit and driving circuit are designed.(5) Monostable circuit, counter and multiplexer of digital circuit are designed with VHDL language, then the circuit functions are simulated and tested with Max+plusII. The communication program between digital circuit and computer, computing program of orientation arithmetic are programmed by Visual Basic language.Experiment shows that the passive acoustic localization system theory is feasible, Then, the whole contents of study are summarized, the existing problems and improving methods are pointed out, Finally, the prospect of acoustic localization technology is presented.