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. GNSS - Global Navigation Satellite System In 1994 in a meeting of the ECAC, a satellite strategy was approved, with as targets: - firstly developing items for an European supplement on the current satellite systems, now called GNSS-1 - secondly designing and defining future satellite systems for civil use (called GNSS-2... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ...

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. This long range RADAR antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. RADAR is a system that uses radio waves to detect, determine the direction and distance and/or speed... See: Animal echolocation: animals emitting sound waves and listening to the echo in order to locate objects or navigate. ...

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.^[1] The Disaster Monitoring Constellation (DMC) consists of five remote-sensing satellites constructed by Surrey Satellite Technology Ltd for the Algerian, Nigerian, Turkish, British and Chinese governments. ... Surrey Satellite Technology Ltd, or SSTL, is a spin-off company of the University of Surrey that builds and operates small satellites. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ...

References

1. ^ S. Gleason et al., Processing of bistatically reflected GPS signals from low Earth orbit for the purpose of ocean remote sensing, IEEE Transactions on Geoscience and Remote Sensing, Vol. 43, No. 6, pp. 1229-1241, June 2005.

External links

• GNSSR-05 workshop, University of Surrey, June 2005.