Contactless Measurement of Hypervelocity Projectile Wake Velocity Distribution

This paper presents a microwave approach to investigate the wake velocity distribution of hypervelocity projectile. The ballistic range measurement is carried out to model the transport of hypervelocity object on the ground. An X-band horn antenna sends a continuous sinusoidal wave with f
_c
= 8.7 GHz to the hypervelocity object and detects the reflected signal. The continuous wavelet transform is utilized to obtain the Doppler frequency shift, and the wake velocity is calculated based on the theory of the Doppler effect. The validity of this experiment is confirmed by comparing the measured projectile velocity with that achieved by a laser-based velocity meter. As a contactless method, this approach does not interfere with the wake flow field. Therefore, the velocity distribution achieved in this paper exhibits better accuracy compared with that obtained from other contact approaches.