Airborne 3D nadir-looking SAR echo numerical simulations for radar depth sounding of fast outlet glaciers and ice-sheet margins

A physical model for electromagnetic (EM) scattering from layered structure with multilayer rough interfaces is established, and the analytical expressions of radar observations are derived based on Kirchhoff approximation (KA) of rough surface scattering and the ray tracing of geometric optics (GO) theory, an efficient and accurate radar echoes simulator for airborne nadir-looking synthetic aperture radar (SAR) radar depth sounding of ice-sheet is developed for analyzing and processing the real radar observations. The radar signal simulator can be utilized to optimize the radar system design and improve radar data processing techniques, which can also be utilized to investigate subsurface structures in planetary exploration. The proposed radar signal numerical simulation method is validated with analytical expressions. With the different simulation configurations and system parameters, the scattering radar echo is simulated numerically by employing our proposed method, furthermore, the influence of ice surface roughness, subsurface roughness, the slopes of mountains, ice depth are investigated and the parameters of radar system on EM scattering fields, and the clear physical scattering meanings are provided. The proposed me thod can be utilized to calculate the radar echoes from layered structure with arbitrary roughness and geological to- pography property.