Multilayer simulations for Martian subsurface radar soundings

We develop a new method of multilayer simulations for interpreting accurately the real radar observations of Martian subsurface radar sounder in the insight of electromagnetic (EM) wave radiation and propagation inside the stratified mediums with multilayer rough interfaces. The multilayer radar echo simulator is developed by employing the Huygens theory, Kirchhoff approximation (KA) of rough surface scattering and the ray tracing of geometric optics (GO) theory to calculate accurately the EM scattering from real Martian topography and subsurface rough boundaries. A clear physical meaning of EM wave radiation and propagation in rough layered mediums is provided for achieving more accurate interpretations of real radar data. The presented method can be utilized to reduce effectively the strong Martian surface off-nadir clutters for discerning the weak subsurface nadir echo masked by surface clutters, which can maximize the ability for detecting the Martian deep subsurface information by improving the signal-to-clutter radio (SCR) and signal-to-noise ratio (SNR). Finally, the proposed method is utilized to test and validate the controversial hypotheses of actual Martian radar sounding data and give more accurate geological interpretations.