Research On Acoustic Precision Target Measurement Technology Under Oblique Incident Conditions Of Projectiles

The target accuracy is an indispensable and important indicator in weapon performance testing,and the most direct detection of the target accuracy is to measure the coordinate position of its impact point.The conventional acoustic target measurement system requires the ballistic line to be perpendicular to the preset target surface.When the ballistic line is not perpendicular to the preset target surface,the obtained measurement result tends to have a large error.Aiming at the problem of large measurement error caused by oblique incidence of projectiles,this paper mainly studies the lattice-acoustic-accuracy target measurement technique under oblique incident conditions of projectiles.In this paper,the relevant characteristics of the projectile shock signal were studied firstly,and several kinds of interference waves in the projectile shock signal were analyzed.The two-dimensional projectile shock wave model was used to illustrate its limitations in the projectile oblique incidence application.Therefore,it was necessary to construct a three-dimensional surface model of the projectile conical shock wave.The traditional acoustic precision target model constructed by projectile shock wave visual velocityv_hwas analyzed,and the T-acoustic precision target model was simulated and analyzed,which showed the measurement problem of the traditional acoustic precision target when the projectile was obliquely incident.Three-dimensional model of projectile shock cone surface was constructed,and the correctness of this model was verified by simulation.The simulation analysis of the oblique incident projectile was realized by using this model.According to the projectile conical shock surface model,three mathematical models of acoustic accuracy target for projectiles oblique incidence were deduced,and the six-point mathematical model of oblique incident acoustics was simulated and analyzed in MATLAB,the influence of projectile velocity,speed of sound,time,position error of the microphone on its positioning accuracy was simulated,and the correctness of this model was fully verified.According to the requirements of the oblique incidence acoustic accuracy target test system,an oblique incident acoustic accuracy target test platform had been built,including the projectile shock signal processing module design,time acquisition and control module design based on STM32,and the upper computer software design.Many model experiments had been conducted on this test platform to verify the feasibility and reliability of the test platform.The acoustic calibration technology of the microphone position was studied,the measurement accuracy of the microphone position could be improved,and the precision of the acoustic accuracy target measurement was improved.A range experiment was conducted,and an effective target of 10m times 10m was arranged in the shooting range experiment.According to the experimental data,the projectile coordinate position was(0.2142m,4.1463m),the pitch angle?was 2.658 degree and the horizontal angle?was-0.252 degree.The projectile coordinates solved by the oblique incidence acoustic six-point model were basically consistent with the projectile coordinates solved by the T-shaped target model.The maximum difference between the measured abscissa was 11.83cm and the maximum difference between the ordinates was 17.92cm.The oblique incident acoustic six-point model was proved to be a good solution to calculate the impact point coordinates,pitch angle?and horizontal angle?of obliquely incident projectiles.Under the condition that the position of the microphone was accurately measured,the model could solve the acoustic accuracy target test problem when the projectile was obliquely incident.