New Technology in Wound Ballistics: The Doppler Radar

The feasibility of using Doppler radar to obtain more accurate measurements of velocity and yaw angle of bullets was investigated.Anesthetized pigs were shot at a range of 9-10 meters, and velocity measurements were obtained using Doppler radar and photocells. The data from the two types of equipment was compared. Excellent correspondence was found between the measurements of entry velocities of low, medium, and high velocity bullets, i.e., an average deviation of less than 1% (range 0-2%). Measurements of exit velocities of low and medium velocity bullets corresponded just as well, but measurements of exit velocities of high velocity bullets was complicated in both methods by signal cluttering caused by fragments of tissue released from the exit wound and by the deflection of the bullet. A Doppler radar was used to follow the movements of the bullet, to determine the velocity, and, if possible, to determine when the bullet stabilizes and the exact yaw angles continuously. We were able to design a system in which even small caliber bullets could be followed for 15-20 meters. It was possible to detect yaw even with these small calibers, and the radar was not disturbed by additional equipment. Using Doppler radar to measure velocity offers important benefits--simple set up, minimal risk of damage to equipment by stray bullets, and very good accuracy. The results of measuring yaw angles of bullets are promising, as far as determining the point of stability is concerned, but further work is necessary to be able to measure the angle of yaw exactly.