Airborne SAR processing of highly squinted data using a chirp scaling approach with integrated motion compensation

This paper proposes a new approach for high-resolution airborne SAR data processing, which uses a modified chirp scaling algorithm to accommodate the correction of motion errors, as well as the variations of the Doppler centroid in range and azimuth. By introducing a cubic phase term in the chirp scaling phase, data acquired with a squint angle up to 30" can be processed with no degradation of the impulse response function. The proposed approach is computationally very efficient, since it accommodates the variations of Doppler centroid without using block processing. Furthermore, a motion error extraction algorithm can be incorporated into the proposed approach by means of subaperture processing is azimuth. The new approach, denoted as extended chirp scaling (ECS), is considered to be a generalized algorithm suitable for the high-resolution processing of most airborne SAR systems.