An optical ambiguity function processor fabricated from off-the-shelf components, which is augmented with preprocessing and postprocessing electronics, is presently demonstrated to process the return echoes of each radar pulse to form the image of the terrain illuminated by a SAR in real time. The reconstruction of the SAR image proceeds by compressing the signal first in azimuth, and then in range, by means of an ambiguity-function generator, which measures the Doppler effect imparted onto the return signal by a target and then measures the range to the target on a pulse-by-pulse basis.
Jerry B. Wood, Jerry B. Wood,
"Real-time acousto-optic processor for synthetic aperture radar", Proc. SPIE 1296, Advances in Optical Information Processing IV, (1 September 1990); doi: 10.1117/12.21266; https://doi.org/10.1117/12.21266