Research On Key Technology Of Miss Distance Measurement Based On Microphone Array

Miss distance measurement is an indispensable indicator o f the weapon system evaluation.It is also one of the most important parameters of various weapons research,the training range of public security,armed police and troops training center.In this paper,to reduce the measurement error,the microphone array is researched,and the principle of microphone array positioning is deeply analyzed.Furthermore,the microphone array technology,signal denoising technology and time delay estimation technology are also improved.The main contents of this paper are as follows:To solve the low accuracy and azimuth ambiguity of the conventional microphone array model,microphone array technology is deeply analysed.A double five element cross array measurement fusion model is construrcted.A criterion of judging the impact point is presented,by which the problem of ambiguous azimuth is solved.According to analyse the performance of double five element cross array model undering different conditions,the pitch angle weighted of double five element cross array algorithm is presented.Finally,the performance of the constructed model is vertified by the different pitch angles,azimuth angles and time delay estimation errors.The experiment results show that the accuracy of the proposed method is much higher than the ones of the XOY and the XOZ five element cross arraies,and the presented algorithm is robust for pitch angle.The noise problems and non-stationary characteristics of the signal collected by the microphone array are worth studying.To solve the influence of a noised signal,the principle of wavelet threshold denoising is researched,by which a new threshold function and an improved threshold formula are simultaneously proposed.Furthermore,the hard threshold,soft threshold,Garrote threshold are employed to estimate the developed algorithm.The experimental results demonstrate that the proposed method can overcome the problems of soft threshold and hard threshold,and solve the problem of denoising on different decomposition scales using the same threshold.Mostly important,it can effectively improve the signal to noise ratio.In this paper,Variable mode decomposition(VMD)is studied,and the prior knowledge of the original signal is considered,What's more combining correlation coefficients algorithm,a new method for extracting intrinsic mode function(IMF)of signals is explored.The new signal denoising algorithm is proposed by combining VMD and correlation coefficients.Theoretical analysis and simulation experiments show that that under the different sampling frequencies and signal to noise ratios,the denoising effect of the proposed algorithm is much better than empirical mode decomposition(EMD).A typical time delay estimation method is studied to solve the problem of delay estimation of microphone array.The characteristics of signal are studied,and to extract the effective signal,the detection criterion of signal energy is designed.An improved wavelet threshold function weighted GCC algorithm is proposed.Then the improved wavelet threshold function is used to filter the noise in the effective signal.and the generalized cross correlation algorithm is used to estimate the time delay of the signals.Simulation results show that the proposed method can improve the accuracy of TDE.A GCC-TDE based on the improved VMD method is proposed.The method firstly extracts effective signal to reduce the amount of computation,which is based on signal energy detection criterion.Then the improved variable mode decomposition method is used to deal with the effective sign als.And the generalized cross correlation algorithm is used to estimate the time delay.The simulation results show that the proposed method can reduce the time delay estimation error.Aiming at the requirement of miss distance measurement based on microp hone array,a miss distance measurement system with a double five element cross array is designed and built.The results have proved that the designed method has good measurement accuracy,The results also verify the correctness and rationality of the proposed algorithm.