Concept and realization of an airborne SAR/interferometric radar altimeter system (ASIRAS)

Cryosat is an approved ESA mission. Its objective is to determine fluctuations in the Earth's land mass and marine ice fields. The mission utilizes a completely new SAR/interferometric altimeter concept, which combines a nadir-looking configuration with pulse-limited altimetry. The concept has been verified by simulations, but no dedicated experimental validation has been performed so far. For this reason, an Airborne SAR/Interferometric Radar altimeter System (ASIRAS) is currently under development in the frame of an ESA contract. Due to the large bandwidth of the system, several components, i.e. the chirp generator, are critical and therefore require innovative solutions. A dedicated software per-forms SAR- and interferometric radar data processing and, in addition, supports internal instrument calibration. ASIRAS is intended to be tested, verified and optimized on a DO 228/100 aircraft carrier during a measurement campaign scheduled fall 2002 in the area of Fram Street north of Greenland. The paper presents mission objectives, the instrument concept of ASIRAS, and critical building blocks.