A NEW SUBAPERTURE APPROACH FOR REAL-TIME SAR PROCESSING

A novel, subaperture approach for high quality SAR processing has been developed at DLR. This approach is based on dividing the received SAR signal (range or azimuth direction) into small subapertures, allowing a quadratic phase variation of up to 115-degrees within one subaperture. With a simple linear correction of the phase variation, the correlation process in each subaperture is reduced to an up/down frequency conversion followed by two moving average operations. By adding all the subapertures coherently, a high resolution impulse response function is obtained, which leads to the same image quality as with the conventional matched filter method. Due to the reduced amount of computation and the subaperture structure, this new approach is especially suitable for real-time SAR processing while providing flexibility to multi-look processing and auto-focus. The concept of a high resolution real-time SAR processor for the DLR's airborne E-SAR system is discussed and a simulation result for evaluating the performance of the proposed algorithm is shown.