Data Volume Reduction for Multi-Channel SAR: Opportunities and Challenges

Abstract:
In this paper, we investigate potentials for data volume reduction in multi-channel SAR. These systems allow for highresolution imaging of a wide swath but, on the other hand, require for their operation the acquisition and downlink of a huge amount of data: together with the intrinsic requirement related to resolution and swath width, this is due to the fact that the effective pulse repetition frequency (PRF) generated by the multiple channels is typically higher than the processed Doppler bandwidth, which introduces a certain oversampling in the azimuth raw data. Therefore, convenient data volume reduction strategies can be proposed, which aim at exploiting the existing correlation between subsequent azimuth samples. In this paper, realistic multi-channel SAR system architectures are considered, and multi-channel raw data are simulated using synthetic as well as real backscatter data from TanDEM-X. We analyse the statistical properties (autocorrelation, Doppler power spectrum, entropy) exhibited by the multi-channel raw signal and discuss the impact of relevant system parameters. Then, possible approaches for data volume reduction for multi-channel SAR are presented, highlighting potentials and limitations.