Sp-461 ers-envisat Symposium

Calibration Transponder

Three precision calibration transponders have been developed by MPB (Canada) based on an ESA prototype and were

delivered to ESTEC in April 2000.

Since the commissioning phase is planned to last only six months following switch-on of the instrument it is necessary

to make use of every possibility of imaging the transponders during that period. Furthermore the placement of the

transponders must be optimized to ensure that each of the seven image mode swaths can be acquired over the

transponders sufficiently to allow for reliable calibration of each beam.