GNSS reflectometry
Encyclopedia
GNSS reflectometry involves making measurements from the reflections from the Earth of navigation signals from Global Navigation Satellite Systems such as GPS. It is also known as GPS reflectometry.
Deliberately bouncing signals off something to learn about it (e.g. radar
, echolocation
) is active sensing; sensing what is already available in the surrounding environment without changing the environment to do so (e.g. eyesight, hearing) is passive sensing. GNSS reflectometry is passive sensing that takes advantage of and relies on separate active sources - the satellites generating the navigation signals.
The UK-DMC satellite
, part of the Disaster Monitoring Constellation
built by Surrey Satellite Technology Ltd
, carries a secondary reflectometry payload that has demonstrated the feasibility of receiving and measuring GPS signals reflected from the surface of the Earth's oceans from its track in low Earth orbit
to determine wave motion and windspeed.
GPS signal reflections have also been used to measure moisture and snow depth.
Deliberately bouncing signals off something to learn about it (e.g. radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
, echolocation
Acoustic location
Acoustic location is the science of using sound to determine the distance and direction of something. Location can be done actively or passively, and can take place in gases , liquids , and in solids .* Active acoustic location involves the creation of sound in order to produce an echo, which is...
) is active sensing; sensing what is already available in the surrounding environment without changing the environment to do so (e.g. eyesight, hearing) is passive sensing. GNSS reflectometry is passive sensing that takes advantage of and relies on separate active sources - the satellites generating the navigation signals.
The UK-DMC satellite
UK-DMC
The UK-DMC satellite is one of a number of satellites in the Disaster Monitoring Constellation . It was built by Surrey Satellite Technology, who operate it via DMC International Imaging on behalf of the UK Space Agency...
, part of the Disaster Monitoring Constellation
Disaster Monitoring Constellation
The Disaster Monitoring Constellation consists of a number of remote sensing satellites constructed by Surrey Satellite Technology Ltd and operated for the Algerian, Nigerian, Turkish, British and Chinese governments by DMC International Imaging...
built by Surrey Satellite Technology Ltd
Surrey Satellite Technology Ltd
Surrey Satellite Technology Ltd, or SSTL, is a spin-off company of the University of Surrey, now fully owned by EADS Astrium, that builds and operates small satellites. Its satellites began as amateur radio satellites known by the UoSAT name or by an OSCAR designation...
, carries a secondary reflectometry payload that has demonstrated the feasibility of receiving and measuring GPS signals reflected from the surface of the Earth's oceans from its track in low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
to determine wave motion and windspeed.
GPS signal reflections have also been used to measure moisture and snow depth.
External links
- Reflecting on the future, The Engineer Online, 28 November 2006.
- GNSS Applications and Methods, Artech House, September 2009.