An acoustic landmine detection confirmatory sensor using continuously scanning multibeam LDV

Acoustic-to-seismic coupling technology using an LDV as a vibration sensor has proved itself as a potential confirmative sensor for buried landmine detection. One of the most important objectives of this technology is to increase the speed of measurements. Traditionally used point-by-point scanning LDVs cannot provide fast measurements. A moving platform that uses 16 LDVs and a continuously scanning single-beam LDV has been used to increase the speed of detection of buried landmines. Recently a multibeam LDV simultaneously probing 16 positions on the ground has been developed and successfully used for landmine detection. In this work, we report the use of a continuously scanning multibeam LDV as a confirmatory sensor for acoustic landmine detection. The multibeam LDV simultaneously illuminates the ground in 16 points spread over a 1-m line. A scanning mirror moves all 16 laser beams across the line. An airborne sound source in the frequency range of 80–300 Hz has been used to excite vibrations in the ground. The system enables scanning a 1-m by 1-m area and provides the vibrational pattern at the surface of the ground in a much shorter time than with previous scanning techniques.