Mobile mounted laser Doppler vibrometer array for acoustic landmine detection

The use of a laser Doppler vibrometer (LDV) to sense the acoustic-to-seismic coupling ratio for buried landmine detection has previously been demonstrated. During these experiments, the LDV is mounted on a fixed platform and the beam moves continuously across the ground. Experiments show that a fixed mounted LDV can achieve scanning speeds up to 3.6 km/h for successful detection of buried landmines in outdoor ground. The problems associated with taking a fixed-mount, scanning LDV and transitioning to a mobile system involve such issues as vehicle vibration, additional Doppler bandwidth due to vehicle speed, speckle noise, and sample time vs. spatial averaging. This paper presents the results of field tests with a moving platform on U.S. Army mine lanes showing that many of these issues can be overcome with an appropriately designed moving platform. The testing involved scanning different types of mines at varying depths and different speeds. Different aspects of the experiment are also discussed.