The forward-looking imaging mode SAR (F-SAR) is much more difficult to achieve high azimuth resolution in comparing with traditional side-looking SAR. It is almost impossible to achieve high azimuth resolution to perform azimuth compression by doing correlation in Doppler-time (f-t) domain like in side-looking SAR. This paper provides a new concept of high azimuth resolution for F-SAR. The Doppler-time histories of F-SAR are expressed as time-Doppler (t-f) format in which the format of the time-Doppler histories is similar with that of side-looking SAR expressed as Doppler-time (f-t) format. There is a very high gradient of time versus Doppler frequency. And the azimuth compression is much more convenient and easy to be performed. The high azimuth resolution can be achieved by doing correlation properly with suitable azimuth references in time-Doppler (t-f) format for F-SAR. The paper will mainly focus on the azimuth resolution in theory.
Shengli Dai, Shengli Dai,
"New approach to achieve high azimuth resolution for forward-looking SAR", Proc. SPIE 4135, Earth Observing Systems V, (15 November 2000); doi: 10.1117/12.494256; https://doi.org/10.1117/12.494256