System for calibrating from the ground a payload of a satellite

A system for calibrating a payload of a satellite, the payload (CU) comprising a multichannel transmitter or receiver comprising one antenna (ANT) per channel, one analogue processing chain (RF1, RF2) per channel and a set of digital integrated circuits (PN), the system comprising a calibration device (DCAL) implemented in the payload (CU) or in a ground station (ST), the calibration device (DCAL) being configured to:

• acquire for all the channels of the transmitter or of the receiver, a digitized calibration signal,
• set a reference channel and, for each of the other channels,
• determine a relative complex gain between the channel and the reference channel, for a plurality of frequencies of the calibration signal, correct the relative complex gain of a relative gain of the antenna (ANT) of the satellite between the channel and the reference channel,
• estimate, from the phase of the relative complex gain, which phase is evaluated for a set of frequencies, a relative propagation delay of the calibration signal,
• estimate, from the phase of the relative complex gain, which phase is evaluated for a set of frequencies, and from the relative delay, a relative phase difference for the set of frequencies,
• deliver a correction of the relative gain, phase difference and delay of the channel with respect to the reference channel for a set of frequencies.