2011 IR&D Annual Report

Radio Frequency (RF) Detection of Small Arms Fire, 10-R8173

Principal Investigators
Thomas C. Untermeyer
Gregory C. Willden
Carl E. Weiss
Andrew R. Cormier
Chuong D. Khuc

Inclusive Dates:  07/01/10 – 12/31/11

Background — For defense purposes, the military has an interest in detecting weapons as soon as possible after their firing or launching from as far away as possible. Optical, Infrared (IR), and acoustic systems exist today that can detect the firing of a variety of weapons. However, these detection methods do not work as well in obscured environmental conditions caused by clouds, fog or rain. Acoustic systems also provide much slower response time and limited range. Since the 1950s, the open literature has reported the possible generation of radio frequency (RF) emissions caused by the launching of a variety of weapons. Passive RF detection of weapon launches could provide a benefit over optical, IR, and acoustic systems by providing fast detection through obscured environments over extended ranges.

Approach — Using lessons learned during previous testing, including developing sensors used to collect RF data from a variety of weapons, researchers attempted to reliably and consistently detect the RF signals caused by the firing of automatic weapons at a distance of more than one-quarter mile (400 meters) and to understand the phenomenology associated with the cause of the RF signals.

Accomplishments — The team developed a test plan and assembled the appropriate antennas and test equipment to collect RF and video data at the SwRI outdoor ballistics range and inside one of SwRI's RF shielded enclosures during the firing of a small arms weapon. Although the team did capture RF signals during this testing, the signals did not occur every time. Also the signals did not provide an adequate signature to differentiate them from other external transmitters.

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