Simulations of direct and reflected waves trajectories for in situ GNSS-R experiments

A simulator was developed to accurately determine the reflection points of Global Navigation Satellite System (GNSS) signals on Earth's surface, offering a unique method to monitor water level variations. The study found that geometric differences between reflection points, when considering Earth as a sphere or ellipsoid, averaged 44 cm for satellites with elevation angles greater than 10° and 1 m for those between 5° and 10°. Integration of Digital Elevation Models (DEM) significantly impacted reflection point accuracy, with errors reaching up to 3.80 m without DEM integration at a minimum elevation angle of 5°. Tropospheric effects also introduced substantial errors, increasing from 43 cm at a 5 m receiver height to 103 m at 300 m. These findings underscore the importance of precise Earth representation and atmospheric corrections in GNSS-R experiments.

Roussel, N., Frappart, F., Ramillien, G., Desjardins, C., Gegout, P., Pérosanz, F., & Biancale, R. (2014). Simulations of direct and reflected waves trajectories for in situ GNSS-R experiments. https://doi.org/10.5194/gmdd-7-1001-2014