System and method for dynamically calibrating one or more radiofrequency channels of a satellite payload

A system for dynamic calibration of a RF radiofrequency circuit of a satellite payload,

• the RF radiofrequency circuit comprising a first radiofrequency chain to be calibrated for amplification and for filtering with or without transposition to a predetermined transposition frequency of a first input signal made up of a temporal sum of a second calibration signal and of a third useful input signal,
• the first radiofrequency chain to be calibrated on a useful frequency chain band lying between upstream a first upstream port for receiving the first input signal and downstream a first downstream port for providing a first output signal, the first output signal being a frequency and temporal response of the first radiofrequency chain to be calibrated to the first input signal;
• and
• the dynamic calibration system comprising:
• a device for injection of the second calibration signal whose waveform is predetermined upstream of the first radiofrequency chain to be calibrated, the second calibration signal being injected directly in digital form or indirectly in analogue form through a second analogue injection chain on a basis of a reference calibration signal, and the band of the second calibration signal being included in the useful frequency band of the first chain to be calibrated;
• and
• a device for compensation of the frequency and temporal response of the first radiofrequency chain to be calibrated, comprising a filter for compensation on the useful frequency band of the first chain to be calibrated, the compensation filter being disposed upstream or downstream of the first radiofrequency chain to be calibrated and the compensation being carried out on a basis of measurements of a fourth signal observed downstream of the first radiofrequency chain to be calibrated and of the compensation filter, or directly downstream of the first chain to be calibrated;
• the dynamic calibration system further comprising:
• a device configured for temporal erasure of the injected second calibration signal from an output signal of the first radiofrequency chain, the device having an analogue or digital subtracter, connected downstream of the first radiofrequency chain to be calibrated,
• wherein,
• the first radiofrequency chain to be calibrated is an analogue chain of a communication receiver comprising a first frequency down-transposition circuit, a first upstream amplification stage disposed upstream of the first transposition circuit, a first downstream amplification stage disposed downstream of the first transposition circuit, and a first output analogue-digital converter, connected at output of the first chain to be calibrated;
• and
• the device for injection of the calibration signal comprises, placed in series, a digital generator of a digital reference calibration signal, a digital-analogue converter, and a second analogue injection chain including an analogue coupler operating as summator of two analogue signals;
• and
• the injection device is configured to inject one or more calibration signals for a temporal sequence covering the useful frequency band on which the first chain is to be calibrated, and to add the one or more calibration signals to the third useful traffic signal;
• and
• the temporal erasure device comprises the digital generator of the digital reference calibration signal shared with the injection device, the digital subtracter, and a third digital chain for providing a replica of the reference calibration signal to be subtracted, adapted in terms of a transposition frequency compatible with the output frequency of the radiofrequency chain to be calibrated and a delay compatible with a propagation time of a signal along a propagation path passing successively through the injection device, the first radiofrequency chain to be calibrated and the compensation filter.

A system for dynamic calibration of a RF radiofrequency circuit of a satellite payload,

• the RF radiofrequency circuit comprising a first radiofrequency chain to be calibrated for amplification and for filtering with or without transposition to a predetermined transposition frequency of a first input signal made up of a temporal sum of a second calibration signal and of a third useful input signal,
• the first radiofrequency chain to be calibrated on a useful frequency chain band lying between upstream a first upstream port for receiving the first input signal and downstream a first downstream port for providing a first output signal, the first output signal being a frequency and temporal response of the first radiofrequency chain to be calibrated to the first input signal;
• and
• the dynamic calibration system comprising:
• a device for injection of the second calibration signal whose waveform is predetermined upstream of the first radiofrequency chain to be calibrated, the second calibration signal being injected directly in digital form or indirectly in analogue form through a second analogue injection chain on a basis of a reference calibration signal, and the band of the second calibration signal being included in the useful frequency band of the first chain to be calibrated;
• and
• a device for compensation of the frequency and temporal response of the first radiofrequency chain to be calibrated, comprising a filter for compensation on the useful frequency band of the first chain to be calibrated, the compensation filter being disposed upstream or downstream of the first radiofrequency chain to be calibrated and the compensation being carried out on a basis of measurements of a fourth signal observed downstream of the first radiofrequency chain to be calibrated and of the compensation filter, or directly downstream of the first chain to be calibrated;
• the dynamic calibration system further comprising:
• a device configured for temporal erasure of the injected second calibration signal from an output signal of the first radiofrequency chain, the device having an analogue or digital subtracter, connected downstream of the first radiofrequency chain to be calibrated
• wherein,
• the first radiofrequency chain to be calibrated is an analogue chain of a communication receiver comprising a first frequency down-transposition circuit, a first upstream amplification stage disposed upstream of the first transposition circuit, a first downstream amplification stage disposed downstream of the first transposition circuit, and a first output analogue-digital converter, connected at output of the first chain to be calibrated;
• and
• the device for injection of the calibration signal comprises, placed in series, a digital generator of a digital reference calibration signal, the digital-analogue converter, and a second analogue injection chain including an analogue coupler operating as summator of two analogue signals;
• and
• the injection device is configured to inject one or more calibration signals for a temporal sequence covering the useful frequency band on which the first chain is calibrated, and to add the one or more calibration signals to the third useful traffic signal;
• and
• the temporal erasure device comprises the digital generator of the digital reference calibration signals of the temporal sequence shared with the injection device, the digital subtracter, and a third digital chain for providing replicas of the reference calibration signals of the sequence to be subtracted, adapted in terms of a transposition frequency compatible with the output frequency of the radiofrequency chain to be calibrated and of gains and delays compatible respectively with gains and propagation times of the one or more calibration signals along the propagation path passing successively through the injection device and the first radiofrequency chain to be calibrated.

A system for dynamic calibration of a RF radiofrequency circuit of a satellite payload,

• the RF radiofrequency circuit comprising a first radiofrequency chain to be calibrated for amplification and for filtering with or without transposition to a predetermined transposition frequency of a first input signal made up of a temporal sum of a second calibration signal and of a third useful input signal,
• the first radiofrequency chain to be calibrated on a useful frequency chain band lying between upstream a first upstream port for receiving the first input signal and downstream a first downstream port for providing a first output signal, the first output signal being a frequency and temporal response of the first radiofrequency chain to be calibrated to the first input signal;
• and
• the dynamic calibration system comprising:
• a device for injection of the second calibration signal whose waveform is predetermined upstream of the first radiofrequency chain to be calibrated, the second calibration signal being injected directly in digital form or indirectly in analogue form through a second analogue injection chain on a basis of a reference calibration signal, and the band of the second calibration signal being included in the useful frequency band of the first chain to be calibrated;
• and
• a device for compensation of the frequency and temporal response of the first radiofrequency chain to be calibrated, comprising a filter for compensation on the useful frequency band of the first chain to be calibrated, the compensation filter being disposed upstream or downstream of the first radiofrequency chain to be calibrated and the compensation being carried out on a basis of measurements of a fourth signal observed downstream of the first radiofrequency chain to be calibrated and of the compensation filter, or directly downstream of the first chain to be calibrated;
• the dynamic calibration system further comprising:
• a device configured for temporal erasure of the injected second calibration signal from an output signal of the first radiofrequency chain, the device having an analogue or digital subtracter, connected downstream of the first radiofrequency chain to be calibrated,
• wherein,
• the first radiofrequency chain to be calibrated is an analogue chain of a communication transmitter comprising a first frequency up-transposition circuit, a first upstream amplification stage disposed upstream of the first transposition circuit, a first downstream amplification stage disposed downstream of the first transposition circuit, and a first input digital-analogue converter, connected at output of the compensation filter;
• the device for injection of the calibration signal comprises, placed in series, a digital generator of a digital reference calibration signal, and a second digital injection chain comprising a digital summator of two digital signals;
• and
• the temporal erasure device comprises the digital generator of the digital reference calibration signal shared with the injection device, the analogue subtracter, and a third digital-analogue hybrid chain for providing a replica of the reference calibration signal to be subtracted, adapted in terms of a transposition frequency compatible with an output frequency of the first radiofrequency chain to be calibrated and a delay compatible with a propagation time of a signal along a propagation path passing successively through the injection device, the compensation filter and the first radiofrequency chain to be calibrated.