The carrier-to-noise ratio that results from phase-sensitive heterodyne detection in a photon-limited synthetic-aperture ladar (SAL) is developed, propagated through synthetic-aperture signal processing, and combined with speckle to give the signal-to-noise ratio of the resultant image. Carrier- and signal-to-noise ratios are defined in such a way as to be familiar to the optical imaging community. Design equations are presented to show that a 10-μm SAL in orbit around Mars can give centimeter-class resolution with reasonable laser power. SAL is harder to implement in the short-wave infrared and is probably not practical at visible wavelengths unless many separate images can be averaged. Some tutorial information on phase-sensitive heterodyne detection and on synthetic-aperture signal processing and image formation is provided.
© 2002 Optical Society of America
(030.5290) Coherence and statistical optics : Photon statistics
(030.6140) Coherence and statistical optics : Speckle
(110.0110) Imaging systems : Imaging systems
(280.6730) Remote sensing and sensors : Synthetic aperture radar
Robert L. Lucke and Lee J Rickard, "Photon-Limited Synthetic-Aperture Imaging for Planet Surface Studies," Appl. Opt. 41, 5084-5095 (2002)