Accession Number : AD0913543

Title :   Tropospheric Refraction Corrections for Airborne Systems.

Descriptive Note : Air Force surveys in geophysics,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Kalaghan,Paul M. ; Altshuler,Edward E.

Report Date : 26 JUN 1973

Pagination or Media Count : 27

Abstract : The main objective of this study is to determine the best method for obtaining range error corrections for airborne systems to be used at low elevation angles in Central Europe. It was first necessary to determine whether the atmosphere can be considered horizontally stratified since essentially all techniques for calculating range error are based on that assumption. For four locations having separations ranging from 56 to 240 km, 292 simultaneous refractivity profiles were obtained. Using a numerical integration technique, range errors based on these profiles were computed for each location to an accuracy of + or -0.1m. The corresponding range errors for each location were compared and found to differ by only 2.3%, thus supporting the assumption of a horizontally stratified refractivity model. It was also found that the range errors had essentially no monthly or even seasonal dependence, and that a correction based on an annual mean value which varied only with elevation angle was accurate to 3.6% of the total range error. Finally it was shown that the range error was correlated with surface refractivity and that an accuracy of 3.4% was possible using a linear regression. (Author)

Descriptors :   (*ATMOSPHERIC REFRACTION, CORRECTIONS), (*TROPOSPHERE, ATMOSPHERIC REFRACTION), RADIO WAVES, ANGLE OF ARRIVAL, REFRACTIVE INDEX, RANGE FINDING, RADIO EQUIPMENT, AIRBORNE, REGRESSION ANALYSIS, POLYNOMIALS, RADIOSONDES, ERRORS, MATHEMATICAL MODELS, NUMERICAL ANALYSIS, METEOROLOGICAL PHENOMENA, AIRCRAFT EQUIPMENT, RADAR SIGNALS, ATTENUATION, RANGE(DISTANCE), EAST GERMANY, BERLIN, POLAND

Subject Categories : Atmospheric Physics
      Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE