Simulations of direct and reflected wave trajectories for ground-based GNSS-R experiments

Simulations reveal that the choice of Earth's surface model significantly impacts the accuracy of GNSS-R (Global Navigation Satellite System Reflectometry) measurements, with planimetric differences averaging 9 cm for satellite elevation angles above 10° and 13.9 cm between 5° and 10°. The study also highlights substantial errors due to angular refraction from the troposphere, which can reach up to 116 m in planimetric terms when the receiver height exceeds 300 m. Conducted at two test sites—Cordouan Lighthouse in France's Gironde estuary and Lake Geneva on the Franco-Swiss border—the research underscores the critical role of digital elevation models (DEMs) in improving measurement precision, with average planimetric differences of 6.3 m without DEM integration. The simulator developed for this study provides tools to optimize GNSS-R receiver placement for monitoring water levels and other surface variations.

Roussel, N., Frappart, F., Ramillien, G., Darrozes, J., Desjardins, C., Gegout, P., Pérosanz, F., & Biancale, R. (2014). Simulations of direct and reflected wave trajectories for ground-based GNSS-R experiments. Geoscientific Model Development, 7(5), 2261–2279. https://doi.org/10.5194/gmd-7-2261-2014