A fundamental relationship that is the foundation for all radar is that a target’s range is proportional to an echo delay time. The actual relationship requires knowledge of the velocity of propagation of the signal whose echo delay time is measured. A typical assumption for radar ranging is to use free-space velocity of propagation. However, atmospheric dielectric properties yield a measurably slower velocity of propagation that is a function of temperature, atmospheric pressure, and especially humidity. This results in range measurement errors. A simplified model is developed to estimate the error in range measurements for airborne ground-surveillance radars.
A. W. Doerry, A. W. Doerry,
"Correcting radar range measurements for atmospheric propagation effects", Proc. SPIE 9077, Radar Sensor Technology XVIII, 90771K (29 May 2014); doi: 10.1117/12.2048977; https://doi.org/10.1117/12.2048977