Design of the interface of a calibration transponder and an altimeter / scatterometer

A transponder system is developed to fulfill the in-orbit calibration of the HY-2 satellite altimeter (ALT) and scatterometer (SCAT). The interaction of a calibration transponder and radar (altimeter / scatterometer) is rather complicated. After a brief description of the two active payloads on HY-2 satellite, several key issues are investigated in detail, including time arrangement and power budget. There are some innovations in calibration strategy, including the pre-distortion technology in ALT calibration and the Single-Input-Multiple- Output (SIMO) technology in the SCAT calibration.