I have been examining stripmap SAR algorithms, mainly Range Migration Algorithm. When I check the textbook examples so far I always saw the data trajectory is larger than scene that is observed. An example from Melvin, Scheer et. al page 309.
As you can see, the platform trajectory roughly travels -20 to 20 and scene is half of it. Similarly, if you check this RMA implementation, this RMA Matlab implementation from the book "Spotlight SAR" by Carrara et. al., you can see the along-track axis of the reconstructed image is actually some subset of trajectory points. Just like the case above.
My question is, what happens in the opposite scenario? For instance in image above, we travel a small distance [-5 to 5] and try to produce, maybe not so precise, the image of the scene [-10 10]. If our antenna does not have high directivity, we should also able to get reflections from targets that are not directly in front of the antenna, but how we should map the frequencies in RMA?
I know that in Stolt mapping of RMA, we shift and strech each azimuth column, but in that case I should retrieve more azimuth columns than I have.. I don't know, if there is a such imaging type in SAR literature, please refer me to correct terminology, I am new to that area so I might be missing correct nomenclature.