Description: The range of surface radars depends on the radio waves propagation conditions. Enough speed and strong changes of air properties occur in the atmospheric boundary layer, especially in its underbody, which substantially influences on the radio waves propagation conditions. Due to what the radar range is inconstant value and must be controlled. The purpose of the article is an argumentation of requirements to the error limit of determination of vertical profile of atmosphere refraction index at control of radar detection range of air objects on extremely low heights. The air refraction index depends on current meteorological conditions, so the measuring facilities of air radiophysics (meteorological) parameters in the atmospheric ground layer must carry out measuring for finite time, in defined spatial portions and with spatial resolution and inaccuracies. On existent norms possible difference between a calculation and experiment at determination of radar detection range must not exceed 20%. This value is taken for initial one. Utilizing the statistical going near determination of the radio waves propagation conditions at which the ground-based radar detection range of air objects on extremely low heights changes more than on a possible value, the permissible inaccuracies of determination of air refractive index, measuring of air temperature and humidity, and also atmospheric pressure are argumentated. Requirements are determined to time and spatial resolutions of atmospheric boundary layer parameters measuring. Time of determination of air refractive index vertical profile must not exceed 10 seconds, and vertical resolution must be up to 25 meters. In lower 200 meter layer for false alarm ratio providing no more than 1 for 1 measuring mean square error of determination of air refractive index gradient must not exceed 0.017 N-unit/meter for the superstandard refraction detecting and 0.025 N-unit/meter for the substandard refraction detection.
Keywords: radar range, extremely low height, atmospheric boundary layer, refraction, refractive index, inaccuracy of measurements, requirements