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Encyclopedia > Satellite constellation

A group of electronic satellites working in concert is known as a satellite constellation. Such a constellation can be considered to be a number of satellites with coordinated ground coverage, operating together under shared control, synchronised so that they overlap well in coverage and complement rather than interfere with other satellites' coverage. Look up Electronic in Wiktionary, the free dictionary Electronic can refer to many things: Objects related to electronics The band Electronic. ... A satellite is an object that orbits another object (known as its primary). ... Coverage is (1) the state of being covered, by insurance, cell phone connectivity or other service that is selectively available, depending on a factor such as location. ... In communications, interference is anything which alters, modifies, or disrupts a message; as it travels along a channel, between a source and a receiver. ...


Low Earth orbiting satellites (LEOs) are often deployed in satellite constellations, because the coverage area provided by a single LEO satellite covers a small area, and the satellite travels at a high angular velocity to maintain its orbit. Many LEO satellites are needed to maintain continuous coverage over an area. This contrasts with geostationary satellites, where a single satellite, moving at the same angular velocity as the rotation of the Earth's surface, provides permanent coverage over a large area. A Low Earth Orbiting satellite (or LEO satellite) is a satellite in an orbit that has a semi-major axis that is less than that of a geostationary orbit. ... Angular velocity describes the speed of rotation. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... A geostationary orbit (abbreviated GEO) is a circular orbit in the Earths equatorial plane, any point on which revolves about the Earth in the same direction and with the same period as the Earths rotation. ...


Examples of satellite constellations include the Global Positioning System (GPS), Galileo and GLONASS constellations for navigation and geodesy, the Iridium and Globalstar satellite telephony services, the Orbcomm messaging service, Russian elliptical-orbit Molniya and Tundra constellations, and the Teledesic and Skybridge broadband constellation proposals of the 1990s. Broadband applications benefit from low-latency communications, so LEO satellite constellations provide an advantage over a geostationary satellite, where it typically takes 125 milliseconds for a signal to get from the ground to geostationary orbit. A LEO satellite constellation can also provide more system capacity by frequency reuse across its coverage, with spotbeam frequency use being analogous to the frequency reuse of cellular radio towers. Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... GLONASS (Russian ГЛОНАСС; ГЛОбальная НАвигационная Спутниковая Система; Globalnaya Navigatsionnaya Sputnikovaya Sistema. ... There are several traditions of navigation. ... This article or section should include material from Geodetic datum. ... The Iridium satellite constellation is a system of 66 active communication satellites and spares around the Earth. ... Logo of Globalstar. ... Elliptical may refer to: Ellipse: a shape and mathematical construct Elliptical trainer: an exercise machine This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... Molniya (lightning) was a military communications satellite system used by the Soviet Union. ... Teledesic was a 1990s proposal to build a commercial broadband satellite constellation for Internet services. ... Broadband in general refers to data transmission where multiple pieces of data are sent simultaneously to increase the effective rate of transmission. ... Application has the following meanings: In general, an application is using something abstract for a more concrete use. ... The term communications is used in a number of disciplines: communications, also known as communication studies is the academic discipline which studies communication. ...


Satellite constellation coverage and geometry – determining the minimum number of satellites needed to provide a service, and their orbits – is a field in itself. Geometry (from the Greek words Ge = earth and metro = measure) is the branch of mathematics first introduced by Thales (circa 624-547 BC) dealing with spatial relationships. ... The largest and the smallest element of a set are called extreme values, or extreme records. ...


A group of satellites very close together and moving in almost identical orbits is known as a satellite cluster.


External links

  • SaVi satellite constellation visualization (http://savi.sourceforge.net/)
  • Internetworking with satellite constellations - a PhD thesis (http://www.ee.surrey.ac.uk/Personal/L.Wood/publications/PhD-thesis/)
  • Lloyd's satellite constellations (http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/)

  Results from FactBites:
 
Satellite Phones | Satellite Cell Phones (585 words)
The reason that satellite phones are still working in situations where other phones don’t is that satellite phones rely on satellites in space for their functioning.
One important thing to keep in mind with satellite phones is that the phone or the phone’s antenna must be located in the open to allow it to have an unobstructed view of the sky.
Satellite phones require a clear line-of-sight view of the satellite to be able to send and receive signals from the satellite.
Satellite constellation - Wikipedia, the free encyclopedia (290 words)
Such a constellation can be considered to be a number of satellites with coordinated ground coverage, operating together under shared control, synchronised so that they overlap well in coverage and complement rather than interfere with other satellites' coverage.
Low Earth orbiting satellites (LEOs) are often deployed in satellite constellations, because the coverage area provided by a single LEO satellite covers a small area, and the satellite travels at a high angular velocity to maintain its orbit.
Satellite constellation coverage and geometry – determining the minimum number of satellites needed to provide a service, and their orbits – is a field in itself.
  More results at FactBites »

 
 

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