Reserch On Transmitting And Receiving Technology In Acoustic Location System

When we have the ammunition equivalent test or the damage effect assessment in the firing range or other weapon test site,a large number of sensors were often needed to collect related signal, including shock wave pressure sensors. The accurate measurement of the sensor position played an important role in the analysis of experimental data.It is clearly not conducive to improve work efficiency,by using tape or other distance measuring instrument to measure coordinates in turn for numerous sensors.Especially when the targets were positioned under flowing conditions,this approach was clearly not able to meet the real-time position measurement. In order to solve this problem, this paper put forward a kind of acoustic positioning solution,and focuses on the acoustic emission and receiving technology of the system.This system adopted the method of time delay estimation which was widely used in acoustic positioning technology of a kind of method.The basic principle was that the microphone receiving acoustic signals emitted by the base station array,since sound waves reached the microphone through different paths, there was a certain time delay between the reception. We can estimate the spatial position of the microphone according to a specific algorithm if the delay can be accurately measured.Acoustic positioning system consists of acoustic emission unit, the sound of the receiving unit and the host machine.In this paper,acoustic signal frequency division encoding was determined through a large number of experiments and signal recognition algorithm that based on discrete Fourier transform theory, and we realized the combination of different frequency acoustic signal output by using STC12C5A60S2 microcontroller; according to the relevant acoustic theory and the actual performance test,we completed the selection of power amplifier and acoustic transducer inthe transmission unit; the wireless communication between the base station and the upper machine was realized with the help of the AS13- TTLwireless serial interface module;we also designed a PC display and control software for acoustic emission which could realize remote acoustic signal coding.We designed a special acoustic sensor by using the logarithmic amplifier circuit and fourth-order bandpass filter according to the specific conditions of acoustic positioning. The large dynamic range of the acoustic sensor can not only keep signal normal without cutting top distortion under high sound pressure,but also make it high-magnification when the sound pressure was low.Finally, we carried out an outdoor experiment on the acoustic emission and receiving unit, which verified the basic function of system, meet the design requirements and technical indicators.