Theoretical Analysis of Soil Freeze/Thaw Process on DDM Waveform and Multipath

Abstract: " In order to extend the applications GNSS-R/IR（GNSS-Reflectometry /Interferometric Reflectometry ) remote sensing technique to soil freeze/thaw process detection, soil(frozen/thawn) mixing permittivity models are employed to calculate the soil permittivity. Bistatic full-polarizationcoherentscattering model and random roughness surface scattering model are used to calculate the coherent and non-coherent scattering, which result in the variations of GPS multipath observables and DDM（Delay Doppler Map） waveforms, respectively. When the soil freeze/thaw process occurs, theoretical simulations indicate that soil freeze/thaw process induce the abrupt permittivity changes and affect the obvious variations of GNSS-R/IR signals.In this way, theoreticalfundamentals for soil freeze/thaw process detections are presented.