Accession Number : ADA310560

Title :   Comparison Between the Scanning Fast-Field Program and Helicopter Data.

Descriptive Note : Final rept.,

Corporate Author : ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM

Personal Author(s) : Noble, John M. ; Barnes, Michael

PDF Url : ADA310560

Report Date : DEC 1995

Pagination or Media Count : 58

Abstract : A study was conducted to compare the Fast Field Program (FFP) to data from helicopters out to a range of 20 km. The purpose of the study was to observe how the FFP predictions compared to helicopters over ranges out to 20 km and determine if the FFP could reliably be used to predict the propagation conditions for acoustic arrays listening for helicopters. The helicopter data consisted of many passes of a variety of helicopters over a period of several weeks to obtain a large set of data collected under many different acoustic propagation conditions. Simultaneous acoustic and meteorological data was collected during the experiment. The meteorological data consisted of surface observations of relative humidity and pressure with winds measured from the surface to 2 km and the temperature measured from the surface to 400 m. This provided a good set of meteorological data to use as input to the FFP for the comparisons. For most of the comparisons made, the signal-to-noise ratio for the acoustic data was quite good which contributed to the comparison. For the cases where the signal-to-noise ratio was not good, the FFP provided a good comparison until the signal was buried in the noise. The results of the comparison shows that the FFP predictions agreed very well with the trends in the helicopter data.

Descriptors :   *METEOROLOGICAL DATA, *HELICOPTERS, *ACOUSTIC ARRAYS, *ACOUSTIC MEASUREMENT, *AERIAL TARGETS, *RANGE(DISTANCE), *SOUND RANGING, PROPAGATION, COMPARISON, SIGNAL TO NOISE RATIO, WIND, SURFACES, SOUND TRANSMISSION, SYNCHRONISM, ACOUSTIC DATA, HUMIDITY, HEARING.

Subject Categories : Helicopters
      Meteorology
      Acoustic Detection and Detectors
      Antiaircraft Defense Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE