Ambiguity suppression by Azimuth Phase Coding in multichannel SAR systems

The Azimuth Phase Coding (APC) technique, proposed to suppress range ambiguities in conventional SAR systems, stands out for its low implementation complexity and its effectiveness for point and distributed ambiguities. This paper investigates the possibility of applying the APC to the new, forthcoming generation of multichannel SAR systems, for high resolution and wide swath imaging, based on Digital Beamforming on receive. The extension of APC to multichannel SAR systems is mathematically described. A new metric is defined to quantify the APC performance. A numerical analysis is developed to characterize the influence on the APC behaviors of the main SAR system parameters. Finally, an example of APC performance is provided, by considering two multichannel SAR systems based on a planar and a reflector antenna.