Development of ASIRAS (Airborne SAR/Interferometric Altimeter System)

ASIRAS is an airborne system designed for sea-ice and ice sheet monitoring. It has been developed by ESA under a Technology Research Program contract. The main sensor of this system is a high resolution Ku-band radar altimeter with 1GHz bandwidth. The observation concept is based on a scaled configuration of SIRAL sensor on board CryoSat. The principle of the measurements is based on a combination of ranging, SAR and Interferometric techniques. The development and the validation of ASIRAS are now completed. The system will be extensively used during the Calibration and Validation campaigns of CryoSat mission. This paper describes the key design drivers and the main features of the system. The key operational parameters of the instrument are discussed, with particular focus on the link between the space-based and the airborne configuration. Finally, the performance of the instrument is presented, based on the results obtained from technical flights and a validation campaign.