Research On Key Technologies Of Bio-inspired Acoustic Direction Finding In Small Two-element Array

Acoustic signal source direction finding is a passive detection technology that takes acoustic wave as the carrier and uses directional acoustic sensor and acoustic sensor array to measure the azimuth of acoustic signal source target.It has been widely used in military and civil fields.In recent years,with the development of UAV,UUV and other miniaturized equipment platforms,the demand for small-size,low-power,high-precision acoustic direction finding equipment is increasing day by day.However,under the condition of limited space size and equipment power,the traditional acoustic direction finding array has the problem of poor Angle resolution and even failure due to the limited sampling frequency and low sensitivity of receiving delay to the azimuth of sound source.By introducing the time-delay amplification mechanism of Ormia ochracea auditory system into the small acoustic direction finding array,the receiving delay of the array can be greatly increased,and the sensitivity of the time-delay to azimuth Angle can be significantly improved,and the accurate direction finding of acoustic signal source can be realized under the condition of limited spatial size and sampling frequency.The purpose of this project,"Research on Key Technologies of Bio-inspired Acoustic Direction finding in Small Two-element array",is to introduce the time-delay amplification mechanism of Ormia ochracea auditory system into small two-element acoustic direction finding array on the basis of detailed analysis of array direction finding principle and influencing factors and in-depth study of the time-delay amplification mechanism of Ormia ochracea auditory system.In this paper,a bionic acoustic direction finding technology based on small binary array is explored,which can achieve high precision direction finding for target acoustic source under the condition of limited space size and sampling frequency.Specific research contents include:Firstly,the principle of dual acoustic array direction finding and common TDOA estimation method are studied,and the factors affecting the accuracy of direction finding and the influence of sampling frequency on TDOA estimation results are discussed.The reasons for the decrease of the accuracy of traditional dual acoustic array direction finding under the limitation of spatial size and sampling frequency are analyzed.In this paper,the amplifying characteristics of the time-delay and amplitude differences between the two ears caused by the coupling mechanism of the Ormia ochracea auditory system were studied,and the feasibility of improving the accuracy of the two-element array acoustic direction finding was demonstrated.Secondly,studied the Ormia ochracea auditory delay amplification mechanism digital rapid implementation method and combined with TDOA estimation technology,it has been based on bionic coupling amplifier and biomimetic composite amplifier of bionic delay amplifier TDOA estimation direction finding technology,realized the space size and sampling frequency under the condition of limited precise direction finding for the aims of the sound source.The performance of bionic amplified TDOA estimation acoustic direction finding technology in noise background is analyzed,and its applicability in noise background with spacing much smaller than wave length array is demonstrated.Thirdly,according to the feature that bionic amplified TDOA estimation acoustic direction finding technology has the highest azimuth resolution at zero azimuth Angle,and introduces the rotation factor,the bionic rotation delay minimization direction finding technology is proposed,which achieves better direction finding accuracy than bionic amplified TDOA estimation acoustic direction finding technology.