Satellite Network Types
What are the different types of satellite networks?
There are different kinds of satellite networks designed for different tasks. Mobile satellite telecommunications services use two types of satellite network - Low Earth Orbit (LEO) and Geostationary (GEO).
Low Earth Orbit (LEO) Satellite Networks
Low Earth Orbit (LEO) satellite networks are made up of a constellation of small satellites that orbit the Earth in a series of planes. In each plane a number of satellites follow each other as they orbit the Earth, and the planes run parallel to each other to provide the radio coverage that is used for the services. The orbiting pattern of LEO satellite networks means that the individual satellites in the constellation are constantly moving relative to the Earth’s surface.
From most locations it is possible to see one or more LEO satellites at any time. Sometimes they may be blocked by physical barriers such as buildings or mountains that block the signal path to the satellite, however, because LEO satellites are always moving the satellites may move out from behind the physical barrier after a few seconds or minutes providing a clear radio path between the user terminal and the satellite.
LEO satellite networks are well suited to mobile applications, where you need to use the service while on the move.
External antennas used on vehicles, vessels and aircraft are generally smaller and relatively inexpensive on LEO satellite networks compared to Geostationary satellite antennas. LEO satellites are also much closer to the Earth (800-1,400 km) than Geostationary satellites (approximately 36,000 km) so latency or voice delay in the network can be considerably less.
Pivotel products that use LEO satellite networks include all Iridium, inReach, SPOT and Globalstar satellite solutions.
Geostationary (GEO) Satellite Networks
Geostationary satellite networks utilise a smaller number of satellites, and each satellite provides satellite coverage to a fixed area of the Earth. Geostationary satellites are generally located above the equator, and follow the Earth’s orbit which means each Geostationary satellite stays in the same place relative to the Earth’s surface.
Geostationary satellites are generally larger and require more power than LEO satellites as they need to cover a much larger area of the Earth’s surface.
Geostationary satellites generally have superior data bandwidth, but since the satellites are around 36,000 km above the Earth will experience greater latency or voice delay than LEO satellites. When using Geostationary satellite phones and terminals in a mobile environment it is preferable to have a high elevation angle, so these terminals work better closer to the centre of the coverage area.
If you require the data bandwidth of a Geostationary satellite service as well as mobility, there are sophisticated antenna options available.
Pivotel products that use GEO satellite networks include all Inmarsat satellite solutions.