Glossary

NGSO

| Richard Handford

NGSO, or non-geostationary satellite orbit, refers to those satellites which occupy either a low-earth orbit (LEO) or medium-earth orbit (MEO). Unlike geostationary (GSO) satellites, LEO (and MEO) satellites do not occupy a stationary position but move in relation to the Earth. LEO satellites can be located as close as a few hundred kilometres, or as high as 2,000 kilometres, above the ground.

Being closer to the earth means satellites in NGSO can provide services with lower latency (i.e. delays) than traditional GEO satellites. However, they are also more costly to run as more satellites are needed to achieve global coverage. Modern constellations typically consist of hundreds or thousands of satellites.

LEO satellites came to prominence in the 1990s with projects such as Iridium, Globalstar and Teledesic offering global voice and data services. However, these services failed to gain significant commercial traction.

A second wave started in 2019 with the launch of LEO satellites by SpaceX-owned Starlink and rival OneWeb. Competitors include Amazon’s Project Kuiper. They aim to provide global broadband connectivity to government, enterprise and consumers, as well as remote backhaul to mobile network operators (MNOs).

The most commonly used bands for LEOs are the Ku (12-18 GHz) and Ka (26.5-40 GHz) bands. Operators are interested in additional spectrum including the E-band (71-76 GHz and 81-86 GHz) and the V-band. Spectrum is typically shared among users, and unlike mobile spectrum licences, is not awarded at auctions but is instead assigned directly.

Glossary Term