A Physical Patch Model with Topography Effects for GNSS-R Land Applications and DDM Dimulations

In this paper, we study the wave scattering problem of land surfaces for Global Navigation Satellite System Reflectometry (GNSS-R) applications. Because the receivers are in the specular direction, both the coherent waves and the incoherent waves make contributions. The effects of Topography slopes and elevations, in addition to the microwave centimeter roughness, influence the coherent waves. Simulation results for Pr/Pt over the 20km by 20km area near the specular point is compared with other models and found to be smaller than coherent model and larger than incoherent model for small rms heights. The results are also found to be smaller than the physical patch model results with elevation effects only. The delay-doppler maps (DDMs) are simulated based on the patch model.