A bit off topic, but where can I find details of the math behind SAR? In my last job I worked on radar systems and I was always curious about SAR. However all

A bit off topic, but where can I find details of the math behind SAR? In my last job I worked on radar systems and I was always curious about SAR. However all the information I found was high level descriptions. There was even some MIT course available on it but they too skipped/avoided the math involved (Im curious to see if I can apply similar techniques to audio)