Showing posts from February, 2023

Fresnel zones, testing GNSS-IR

The ground (or water) reflection footprint of GNSS satellites (drawn as Fresnel ellipses) helps to determine how to use that free signal to measure surface water levels, see this remarkable paper by Karegar et al. , a technique already verified to monitor soil moisture, vegetation water content, and snow depth among others, see the multiple contributions pioneered by Kristine M. Larson . The picture shows preliminary tests at G├╝emes lake , Azul, Buenos Aires province.