Study On Explosion Height Measurement By Acoustic Location Of Explosion Point

The explosion height of empty bomb is closely related to the damage degree of the target.The higher explosion height may reduce the damage degree to the ground target.On the contrary,The lower explosion height may reduce the damage area.Only a proper explosion height can obtain the best damage effect.Therefore,the explosion height of air bomb is one of the important performance indexes in the process of weapon test and evaluation.It is meaningful to accurately measure the explosion height for the weapon design and identification.This paper mainly focuses on the problem of air blast bomb explosion height measurement.The main tasks can be summarized as follows:The estimation of time difference of arrival（TDOA）is the basis of passive acoustic positioning explosion height measurement algorithm.The estimation accuracy of TDOA will directly affect the explosion height measurement accuracy.In the low signal-to-noise ratio（SNR）environment,the generalized cross-correlation（GCC）based TDOA estimation algorithm will produce large errors.Aiming at this problem,an improved GCC method is proposed in this paper,which improves the TDOA estimation accuracy under the condition of low SNR by optimizing the weighting function of the GCC method.It lays a foundation for the follow-up research on the bomb height measurement algorithm based on the TDOA.In view of the problems that the localization accuracy of the existing sound source localization methods is greatly affected by the arrangement of the sensor and the sound source,and the localization accuracy is rather poor when the sensor arrangement is not good,a combined weighted 3D localization bomb height measurement method is proposed in this paper.Moreover,the Cramer-Rao Lower Bound（CRLB）of the sound source location is deduced,and the localization performance of the proposed algorithm is theoretically analyzed.The proposed combination weighting method uses 5 acoustic sensors,and randomly selects 4 sensors from the5 acoustic sensors as a group,and a total of 5 groups can be formed.Localization can be performed by each group of sensors independently.Thus,5 groups of preliminary explosion position measurement results can be obtained,and then the combined weighting technology based on the CRLB is used to combine and weight the 5 groups of preliminary measurement results to obtain the final estimated result of the explosion position.Last but not least,the validity of the proposed algorithm is confirmed by plenty of simulation experiments,moreover,the author compares the proposed algorithm with some existing positioning algorithms like the least squares（LS）algorithm,the weighted least squares（WLS）algorithm,and the two-step weighted least squares（2WLS）algorithm,which demonstrates the superiority of the proposed algorithm.In order to further study and verify the algorithms of the explosion height measurement,a system is designed to realize the explosion height measurement.The system is composed of acoustic sensor array module,front-end signal processing module,data acquisition card module and PC module.After completing the system design and debugging,the actual explosion height measurement experiments are carried out indoor and outdoor using the designed system,and some measured data are collected.Then,the measured data are processed by the proposed combined weighting algorithm.The experiments also show that the explosion height measurement system designed in this paper can meet the requirements of explosion height measurement,and also proves that the proposed algorithm can effectively realize the explosion height measurement.