I'm not familiar with SAR, but it seems like they could use more than just 2 antennas to produce a more directional receive array. I work with HF radars (2-30 MHz) and this is basically what we do. There is a lot of clever engineering out there - that one doesn't need to be too clever to apply.
Yes - this idea has definitely taken over my imagination. A different research group (https://www.cresis.ku.edu/) has been working on this, but the processing techniques are still evolving.
Do you have papers describing y'all's processing? I'd love to learn more!
I do have papers. I recently wrote a paper where we used backscatter from container ships to calibrate our radars. I'll try to email it to you, but here it is:
