Objective:The objective of the activity is to develop the methodology for the characterisation of Ground station G/T based on the use of radio stars (like the sun or the moon) up to W band.
Targeted Improvements:Procedures for calibration of a ground station with radio stars taking into account the atmospheric absorption and solar emissions.
Description:The assessment of the G/T of a Ground Station for SatCom services is a critical element for various types of missions. If no space signals are available for this purpose (e.g. the satellite is still to be launched) or if the parameters of these signals are not known then the emission of radio stars can be used as a reference for the calibration of the G/T of a ground station. The choice of the radio star depends on parameters like the dimension of the antenna, the operational frequency band, the location of the station, the intensity of the radio star emission and its angular dimension as seen from the receiver.
In general standard procedures have been developed, mostly for C, X and Ku band and large antennas (e.g. see ITU-R. rec. S.733-2). As the frequency of space systems increases (with a future projection to 70/80 GHz band) the current procedures for calibration of a ground station with radio stars need to be reviewed and updated to address anumber of issues, including the atmospheric absorption and the solar emission at those frequencies.The use of ground radiometric techniques can solve those issues since it could also measure the emission of the radio star, provided that its design permits the characterization of radio sources like the sun and the moon.Hence in this activity a set of radiometric algorithms and procedures shall be developed, based on radiometric measurements of the radio emission of the stars, which shall be applicable up to W band. The algorithms and procedures shall be tested on an operational Q/V-band Ground-Station. Reports shall be issued for inputs to radio regulatory bodies.