Data compression device for SAR application

On board data compression techniques for synthetic aperture radar are of great importance for reducing the high data rate of wide swath, high resolution SAR. One of the most efficient compression techniques for SAR raw data has been developed and applied for the Magellan Mission. The compression ratio of Magellan 8 to 2 put a strong limit on signal to noise ratio (8 dB), lower compression ratios more suitable when higher SNR (8 to 4 or 8 to 3) are required, are not feasible in term of memory requirement with the Magellan approach. In the frame of the ESA program "Imaging Altimeter Bread Boarding" an algorithm has been developed to overcome the memory requirement problem which is based on the same theoretical principle of the Magellan algorithm and is able to compress 8 bit I and Q component data into 2, 3 or 4 bit data. A programmable device called Data Rate Reduction Unit DRRU (able to perform different compression ratios) based on an ASIC has been developed which implements the compression scheme and it's able to work to a speed up to 20 MHz. Speed limits, due only to ASIC technology can be easily overcome in the next years to reach speeds up to 100 MHz.<
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