A fully software GNSS-R receiver for soil dielectric constant monitoring

GNSS Reflectometry is an emerging technique used for the remote sensing of soil surfaces. In this contribution an application of dielectric constant retrieval is presented. Both direct and reflected GPS signals were collected by a fully software receiver mounted on-board an aircraft. The reflected signal was processed with an open loop approach, obtaining Delay Doppler Maps (DDMs) and corresponding Delay Waveforms. Signal to Noise Ratios (SNRs) time series were estimated from (non coherently) integrated Delay Waveforms. To take into account variations of system parameters from nominal values, a calibration was performed considering signals reflected from a water lake. Finally, the retrieval process able to estimate dielectric constant of soil surface from evaluated SNR was applied and the results showed good correlation with fields´ flooding state.