A NEW FORMULA FOR SAR SPATIAL-RESOLUTION

The fundamental limits of SAR spatial resolution is investigated in th is paper. Conventional SAR resolution formulas are not applicable to u ltra-wideband and wide-beam systems since they do not consider the dep endence of system frequency response in the along- and across-track di rections, We derive an expression for the SAR transfer function, from which the impulse response function may be determined. A general resol ution formula is also obtained directly from fundamental time-frequenc y relations which agrees with conventional formulas in the narrow-band and narrow-beam limit. The new resolution formula is accurate provide d the system has a large ratio of integrated mainlobe-to-sidelobe ener gy and the distance to the imaged area is much larger than the longest transmitted wavelength.