Surrey Satellite Technology Ltd (SSTL) has successfully demonstrated an innovative method of measuring winds and waves from space, using GNSS Reflectometry. This paves the way for a cost effective satellite system supporting the maritime sector and the organisations that rely on this information and it also offers improvements to weather services and climate research.
The measurements were taken from an instrument developed by SSTL, the SGR-ReSI, (Space GNSS Receiver Remote Sensing Instrument) which is flying on-board TechDemoSat-1, a technology demonstration satellite which was launched in July 2014. SSTL’s SGR-ReSI collects the signals from GPS and other navigation satellites after they have been reflected off the ocean surface and processes them into images called Delay Doppler Maps, from which ocean roughness and wind speed measurements at the sea surface can be interpreted.
The technique works in a similar way to existing scatterometric radar from satellites, however it eliminates the need for a transmitter and can process up to four reflections from different GPS satellites simultaneously, presenting an opportunity for collecting data more regularly and in a denser grid across the globe. By flying the receivers on a constellation of small satellites GNSS Reflectometry data could be used to map all of the Earth’s ocean surface with refreshed data every couple of hours, and this would be of enormous benefit to the maritime industry who depend on wave height and wind speed predictions for optimum ship routing, insurance claims, oil and gas rig operations, undersea cable laying and fishing conditions. Such wind speed and wave height measurements are currently very difficult to make over the open ocean in timely manner and in a dense enough grid to be useful.