Numerical simulation of polarimetric radar pulse echoes from the lunar regolith layer with scatter inhomogeneity and rough interfaces

摘要

To explore the potential utilities of lower-frequency (L band) radar pulse penetration on Moon exploration, a theoretical model of stratified lunar regolith media and numerical simulation of polarimetric radar pulse echoes are developed. The lunar regolith layer consists of the low lossy regolith layer with randomly rough top and bottom interfaces, and a layer of random stone scatterers (spatially oriented oblate spheroids are assumed) is embedded and overlays the underlying rock media. The time domain Mueller matrix solution derived from vector radiative transfer formulations contains seven scattering mechanisms of the stratified media: surface scattering from the rough top and bottom interfaces, volumetric scattering from random stone scatterers, and their multi-interactions. Temporal characteristics and structure of the polarimetric echo profile as functional dependence on model parameters such as the layer thickness and the content of FeO + TiO2, are numerically simulated and well display an image of regolith structures. Polarimetric pulse echoes might reveal rich information on the lunar regolith layer depth and other structure properties and might demonstrate a potential new way to explore the Moon surface in the future.