Development of GNSS-R started about two decades ago for altimetry. This moment international and interdisciplinary geophysical and engineering research work on it. GNSS-R remote sensing exhibits unique characteristics to complement existing active and passive Earth Observation Systems.
A few satellite missions are in preparation, all focused on ocean remote sensing on a nearly global scale. A GNSS-R experiment will be conducted on the UK TechDemoSat-1 scheduled for launch in 2015. NASA plans to launch the eight satellite CYGNSS (CYclone GNSS) constellation in 2016. ESA has funded activities related to the PARIS In-Orbit Demonstrator (PARIS-IOD). And recently initiated international industrial and scientific studies to install a GNSS-R experiment aboard the International Space Station with planned launch in 2019. [Helmholtz-Zentrum Deutsches GeoForschungsZentrum 2015]
GNSS-R has been contributing to improved global numerical weather forecasts since 2006. In addition the data are currently widely used for numerous applications in atmospheric and climate research. [Helmholtz-Zentrum Deutsches GeoForschungsZentrum 2015]
The UK-DMC satellite, part of the Disaster Monitoring Constellation, carries a secondary reflectometry payload that has demonstrated the feasibility of receiving and measuring GNSS signals reflected from the surface of the Earth's oceans from its track in low Earth orbit to determine wave motion and windspeed.[ S. Gleason et al, 2005][ M. P. Clarizia et al, 2009] GPS signal reflections have also been used to measure moisture and snow depth.[ Phil Berardelli, 2009]