Procedures for in-flight calibration of satellite spectral equipment

The paper presents procedures developed for in-flight calibration of satellite spectral equipment (by solving direct and inverse problems in the theory of radiation transfer in the atmosphere) using quasi-synchronous sub-satellite point measurements. Also presented are the results of processing and analysis of several sessions of multi-level measurements conducted at the Zyabrovka test range (Republic of Belarus, Gomel region). Measurements taken from ground and air used spectral instrumentation developed at the Airspace Research department of Sevchenko IAPP of BSU to support satellite test ranges on the ground. Verification results are provided for measurements taken on the ground, in air and in space. Used for verification of the ground and space measurements were data from the multi-spectral spacecraft Sentinel-2.