Multi‐incident angle approach to retrieve soil parameters for specular scattering

Abstract

Bistatic configuration provides many advantages over monostatic configuration and possesses the potential of future SAR missions. Therefore, the authors have carried out experiments with bistatic scatterometer to characterise soil parameters, that is, soil texture, soil moisture and surface roughness in specular direction. The retrieval of soil parameters requires a priori information and this has been acknowledged in this study with the use of multi-incident angle approach. First, the authors have critically analysed the angular response of specular scattering coefficient (σsp o) with varying soil parameters and this critical analysis led to the development of normalised specular scattering coefficient (Δσsp o) which is function of surface roughness only. These observations were verified by the simulation study based on Kirchhoff scalar approximation (SA). Therefore, normalised specular scattering coefficient was used to retrieve surface roughness and correspondingly this surface roughness value was used to compute dielectric constant of soil with SA. Thereafter, soil texture and soil moisture were retrieved. Good agreement was observed between retrieved results and observed ground truth data.