Daily Thermo-Elastic Distortion Characterisation during Antenna In-orbit Test for Geostationary Satellites

Abstract

Before bringing a new satellite into service after launch, in-orbit testing (IOT) is essential to compare in-flight performance with on-ground references. Antenna IOT is essential to remove any mechanical depoint in order to optimize the alignment of the antenna and therefore RF performance. Depending on the frequency band of operation, thermo-elastic distortion (TED) evaluations could play an important role into the determination of the correct amount of mechanical correction to apply to the antenna. It is in fact essential to discriminate between a fixed contribution derived from an authentic geometry misalignment and an expected TED behavior. The aim of this paper is to describe the methodology to show the correlation between the antenna thermal behaviour, as-measured in-orbit, and its predictions over a period of 24 hours for the Inmarsat-6 F1 Ka-band commercial payload.