Satellite discrimination from active and passive polarization signatures: simulation predictions using the TASAT satellite model

The Air Force Research Laboratory is interested in developing techniques for characterizing and discriminating satellites in Low and Geo-synchronous Earth Orbit (LEO and GEO). Certain materials used in constructing satellites possess unique polarization and wavelength dependent properties that may be useful for satellite discrimination and classification. In this work, we use the TASAT simulation to produce polarization renderings of detailed satellite models, with active and passive illumination, to predict polarization signatures of satellites in various Earth orbit scenarios. TASAT is a detailed tracking and controls simulation developed for modeling electro-optic tracking and imaging scenarios. Polarization renderings from passive illumination provide Stokes parameters representative of material polarization effects for the observed wavelength bands. Active illumination allows the incident polarization state to be changed. Thus, with suitable illuminating states and corresponding Stokes measurements, Mueller matrices may be formed from the active satellite returns, providing additional polarization signature information. Degree-of-polarization (DOP), diattenuation and retardance values calculated from the Stokes parameters and Mueuller matrices provide the polarization signature needed to test for satellite discrimination. We examine the variation of these polarization signatures for different satellite models situated in LEO and GEO observation scenarios. Signature variations for a visible and IR wavelength are considered. The results provide an indication of the feasibility of using material polarization properties for satellite discrimination to within the accuracy of our current materials database and polarization rendering capabilities.