Abstract
Three dimensional imaging of planetary and lunar surfaces has traditionally been the purview of Synthetic Aperture Radar payloads. We propose an active imaging technique that utilizes laser frequency diversity coupled with spatial heterodyne imaging. Spatial heterodyne imaging makes use of a local oscillator which encodes pupil plane object information on a carrier frequency. The object information is extracted via Fourier analysis. Snapshots of the encoded pupil plane information are acquired as the frequency of the illumination laser is varied in small steps (GHz). The resulting three-dimensional data cube is processed to provide angle-angle-range information. The range resolution can be adjusted from microns to meters simply by adjusting the range over which the illuminator laser frequency is varied. The proposed technique can provide fine resolution contour maps of planetary surfaces having widely varying characteristics of importance to science exploration, such as the search for astrobiological habitat niches near the surface of heavily irradiated Europa. This information can be used to better understand the geological processes that form the surface features, and help characterize candidate potential habitat sites on the surface of Europa and other planetary bodies of interest. In this paper we present simulations and experimental data that demonstrate the concept.