INTERNAL CALIBRATION PROCESSING AND PROCESSOR NORMALIZATION

The ENVISAT ASAR instrument incorporates a complex calibration network [1] to monitor the instrument gain through a series of different calibration pulses. This is done on-board for all modes during nominal operation on an antenna row-by-row basis and then downloaded together with the scientific data to be used on the ground processor to derive the correct normalization factors and to monitor possible gain variations. This data is also used by the processor to derive the replica of the transmitted signal, which can be further used to perform the range compression as well as a normalization factor.