Atmospheric Correction for the Troposphere and Stratosphere in Radio Ranging Satellites

Since the barometer measures the weight of the overlying atmosphere, it follows by the law of Gladstone and Dale that the height integral ∫(n − 1)dr of the atmospheric refractivity for radio microwaves, taken from ground level up to the top of the stratosphere, is in a dry atmosphere directly proportional to ground pressure. The refractivity integral, therefore, can be determined without detailed knowledge of the height distribution of the refractive index, which not only simplifies the derivation of refraction formulas in which atmospheric models have been used hitherto, but also improves their accuracy. The range correction for troposphere and stratosphere to be subtracted from the observed microwave distance will be given by the formula Δs(meters) = 0.002277 sec z[p + (1255/T + 0.05)e − 1.16 tan2 z] where z is the zenith distance, p is the total barometric pressure and e is the partial pressure of water vapor, both in millibars, and T is the absolute temperature in degrees Kelvin.