Study On Burst Point Localization Technique Based On Wireless Sensor Network

In the process of artillery weapon-system was tested and finalized the model, carry out practical attack experiment and measure burst point or miss distance, so that we can evaluate the effect and accuracy. Three-dimensional(3-D) coordinate measurement of burst point was one of the most important means of the weapon performance evaluation.The target localization technology based on passive acoustic detection has been widely concerned. The technology uses microphone array to capture acoustic signal, and calculate the 3-D coordinate of the sound source using time-delay estimating and localization algorithm. This thesis combines small-aperture array and wireless sensor network(WSN) technology, and put forward a burst point acoustic localization system. In a test area, the system layout many microphone arrays which are formed a wireless sensor network. Target locating is divided into two steps: firstly, the single array capture explosion signal and estimate the time-delay which is used to calculate the azimuth angle and pitching angle between the target and the array; secondly, using the angle information several arrays transferred and consider the arrays’ location information to calculate the coordinate of the target by the method of intersection. The single test array is both independent and unified: independence means every array calculate angle information by itself, and do not need to be with other arrays on time synchronization; uniformity means when locating the target the arrays need to form a sensor network with each other. The system has advantages of real time capability, low communication complexity and small amount of data transmission.This thesis puts forward small-aperture tridimensional five-element array and expounds directional algorithm based on time difference of arrival(TDOA). By comparing several time delay estimation algorithms we select a suitable one for explosion signal. When the burst point closes to the array, due to the large explosion sound pressure it will generate a topless signal while the sampling signal is beyond the measure range of sensor. Put forward a time delay estimate algorithm based on polynomial matching to deal with this topless signal and the validity of the algorithm has been verified. The thesis lists the factors affecting directional performance, analyses the factors affecting azimuth angle precision and pitching angle precision, uses MATLAB to make some simulation. The problem using several arrays’ directional information to locating the burst point by least-squares algorithm(LS) is studied, the positioning accuracy can be improved when arrays are redundant.For this localization system, this thesis expounds the hardware and software design in detail. Working principle of the system is given and according to the function the system is divided into acoustic signal acquisition module, signal processing module, wireless communication module and upper machine, the function and design of each part are introduced.Finally, the research achievement above is applied to the acoustic localization system, and the feasibility of the whole system is verified though the outdoor experiments.