Bistatic Scattering Forward Model Validation Using GNSS-R Observations

Abstract

In this paper we advance a previously developed bistatic scattering forward model to include the circularly polarized incident and scattered waves, which is the case for Global Navigation Satellite System (GNSS) reflectometry. This model development enables retrieval of soil moisture from Signals of Opportunity (SoOp) bistatic observations, e.g., from the Cyclone Global Navigation Satellite System (CYGNSS) observations and GNSS Reflectometer Instrument for Bistatic Synthetic Aperture Radar (GRIBSAR). In order to validate the forward model with measured data, we present a method to construct the Delay Doppler Map (DDM) from simulations of the forward model. The forward model Radar Cross Section (RCS) predictions will be compared with actual measurements. The validated model is intended for use in soil moisture retrievals.

Forward Scatter Radar Meets Satellite: Passive Sensing of Aerial Target Using Satellite Communication Waveforms

“…I/Q demodulation is often used to realize the tracking loop. According to [24], code correlation and symbol elimination are performed on the received signal after the down conversion, and the correlation result after signal processing can be obtained as…”

“…Then the output of the code correlation processing of the two signals can be considered to be coherent, and the amplitude of the code correlation results can be obtained. According to [24], since each processing cycle is within a few milliseconds of single-chirp integration time, we can regard the frequency of direct signal and echo signal as constants. For direct signals, this assumption is widely used in traditional navigation satellite signal processing; therefore, the suppression of direct wave signal can be completed by a notch filter.…”