Delay Doppler Map from HydroGNSS

Just three months after launch, the European Space Agency’s twin HydroGNSS satellites are already proving their capabilities in orbit. By exploiting reflected signals from navigation satellites – the sophisticated technique they use to generate Delay Doppler Maps in order to ‘scout’ for water across Earth’s surface – these compact satellites are beginning to reveal the scientific potential they were built to unlock, even while still in their commissioning phase.

The image is an early example of two Delay Doppler Maps of reflected GNSS signals captured simultaneously by HydroGNSS-2 over Central Africa within two weeks of launch.

The left image is a reflection from E1 navigation signals generated by Galileo satellite ID27, and the right is from GPS satellite ID21. The strength of these reflections is related to a number of factors on the surface one of which is the soil moisture, and this parameter will be recovered using processors developed by science partners.

Read full story: ESA’s HydroGNSS on track to scout for water