GNSS Pseudo Interference Reflectometry for Ground-Based Soil Moisture Remote Sensing: Theory and Simulations

The Global Navigation Satellite System Pseudo Interference Reflectometry (GNSS-PIR) is proposed for ground-based soil moisture remote sensing in this letter. It combines the signal received by the up-looking right-hand circularly polarized (RHCP) antenna with that received by the down-looking left-hand circularly polarized (LHCP) antenna to form an oscillatory carrier to noise ratio (CNR) waveform. The analyses of waveform quality and parameters' sensitivities to soil moisture in comparison with GNSS Interferometric Reflectometry (GNSS-IR) indicate that both the amplitude and the phase of GNSS-PIR waveform at high elevation angles are available for soil moisture determination. Soil moisture inversion based on Monte Carlo simulations shows that GNSS-PIR obtains better inversion accuracy than GNSS-IR.