Michael T. Barnes
U.S. Army Res. Lab., Battlefield Environment Directorate, White Sands Missile Range, NM 88002
A study was conducted to compare the fast field program (FFP) to data obtained from helicopters. The purpose of the study was to see how well FFP predictions would compare to helicopter data over ranges out to 20 km and determine if the FFP could be used to reliably predict the propagation conditions for acoustic arrays listening for helicopters. Over a period of 2 weeks acoustic data from several helicopters with various flight paths out to a range of 20 km was recorded. At the same time meteorological conditions were also noted. These included temperatures up to 400 m, relative humidity, barometric pressure, wind speed, and wind direction up to 2000 m. The results were very promising and in most cases provided a good comparison until the helicopter signal was buried in background noise.