With satellite Internet, Internet access is provided viasatellite. There are two technical approaches, which essentially differ in the delay time and thus in the possibility of fast interaction: Internet access via a GEO satellite for broadcast services such as Internet television, or the use of LEO satellites, which are characterized by short latency times.
Satellite Internet via GEO satellites
GEO satellites are satellites that occupy a geostationary position and are stationary above the equator at a distance of 35,786 km from the Earth's surface. These satellites are suitable for broadcasting Internet television and other broadcast services. Because the propagation time of the radio waves from the ground station to the satellite and back to the ground station is several hundred milliseconds, satellite Internet using GEO satellites is unsuitable for applications involving time-critical interaction. Control signals sent to the satellite via the uplink reach it only after more than one hundred milliseconds. These latency times also make GEO satellites unsuitable for voice communication, which is severely impaired by the high latency.
In general, the downlink of GEO satellites can be received with existing satellite receiving equipment. Since the uplink is transmitted on a different frequency, another satellite receiving equipment or a multifeed adapter must be installed.
Satellite Internet via LEO satellites
Satellite transmission via GEO and LEO satellites differ in latency. The short distances between ground station and LEO satellites of less than 1,000 km and the large number of LEO satellites that make up a project shorten latency and ensure continuous connectivity to receiving equipment via their handovers. LEO systems offer the same advantages as DSL methods with comparable ping times. These are between 10 ms and 100 ms. Another advantage is worldwide availability. This means that Internet can also be provided to underserved regions where neither wired technology nor mobile technology is feasible.
Since the developments in the early 1920s are overflowing, only a few important and partially realized projects are listed here as examples.
Starlink by the company SpaceX is an extremely extensive project with 42,000 LEO satellites spread over 20 orbital planes. The data rates of Starlink are up to 430 Mbit/s. The Starlink project is scheduled for completion in 2022.
Amazon 'sProject Kuiper is another satellite Internet that uses 3,236 LEO satellites distributed in three different orbital planes. 784 satellites are at an orbital altitude of 590 km, 1,296 at an altitude of 610 km and another 1,156 at an altitude of 630 km.
The inclination angles of the satellite orbits are calculated to provide satellite Internet to over 90% of the Earth's population. According to the current schedule, the Kuiper project should be fully realized with all satellites no later than 2029.
OneWeb is a project from the United Kingdom, which is expected to work with 6,372 in the final stage. The ground stations that receive the satellite signal relay it to users via fiber or radio. Unlike Starlink, OneWeb 's LEO satellites orbit the Earth at an altitude of 1,200 km. Due to the slightly higher orbit and the smaller number of satellites compared to Starlink, the latency is slightly higher. The connection to less populated areas is to be established by radio transmission.
OneWeb's LEO satellites have an Inter Orbit Link (IOL) to GEO satellites, with which they operate in laod balancing.