I'm trying to understand how a SAR system is able to place returns it receives in range space.
Consider the scenario when an airplane is passing over terrain and is imaging it using SAR, as shown in this image from radartutorial.eu:
If it relies on the timing of the return, it seems that there would be ambiguous cases where a tall object further in the swath could have returns that are received earlier than a short object in the near swath. How would a SAR system ever sort out the elevation of the terrain being scanned in the swath?
From what I've found it doesn't seem like there is any sort of servo tracking the beam along the swath width (and it would have to be moving quite fast for this to work). This leads me to think that there must be some signal processing wizardy used to sort these returns that prevents timing ambiguities. What is going on?