Satellite communication system for a continuous high-bitrate access service over a coverage area including at least one polar region

Patent metadata

Field	Value
Publication number	US-2015358861-A1
Application number	US-201414453303-A
Country	US
Kind code	A1
Filing date	Aug 6, 2014
Priority date	Dec 23, 2013
Publication date	Dec 10, 2015
Grant date	—

Abstract

A system comprises a constellation of satellites placed in non-geostationary orbit, user terminals located in a coverage area, and N anchor stations able to ensure bidirectional communications with the user terminals by way of at least one satellite. The system furthermore comprises a network of routers interconnected with one another and to the Worldwide Internet Network, each anchor station is connected to the Worldwide Internet Network by way of a router, and each anchor station comprises a management device for managing the handovers to ensure service continuity for the communications. This management device is able to control the handovers between the successive orbiting satellites progressing over the coverage area, the handovers between anchor stations, or the handovers between simultaneously successive satellites and anchor stations.

First claim

1 . A satellite communication system for providing a continuous high-bitrate access service over a terrestrial coverage area including at least one polar region, comprising a constellation of satellites placed in elliptical orbit around the Earth with an apogee at an altitude of less than or equal to 20000 km, user terminals located in the coverage area, and at least two anchor stations distributed on the Earth and able to ensure bidirectional communications with the user terminals by way of at least one orbiting satellite progressing above the coverage area, wherein said satellite communication system further comprises a network of routers interconnected with one another and to the Worldwide Internet Network by dedicated local terrestrial communication pathways, wherein each anchor station is connected to the Worldwide Internet Network by way of routers, and wherein each anchor station comprises a management device able to control handovers of the communications between the orbiting satellites progressing successively above the coverage area and between the anchor stations, and simultaneous dual-handovers of the communications between satellites and anchor stations.

2 . The satellite communication system according to claim 1 , wherein each anchor station, each router, each satellite and each user terminal comprises a respective navigation receiver allowing them to synchronize amongst themselves and to synchronize all the handovers of the communications between the satellites and/or the anchor stations.

3 . The satellite communication system according to claim 1 , wherein, at each instant, the user terminals and the anchor stations ensuring the communications heading for the user terminals are situated in an area of visibility of at least one satellite and wherein the areas of visibility of two consecutive satellites comprise an overlap area called the handover area, the handovers of the communications destined for a user terminal being carried out when the user terminal is situated in the handover area.

4 . The satellite communication system according to claim 3 , further comprising an operations planning centre connected to the anchor stations by way of the network of routers, the operations planning centre being able to regularly receive the ephemerides of each satellite of the constellation and to form a general plan of all the handovers of the communications to be carried out successively over time between the satellites and/or between the anchor stations.

5 . The satellite communication system according to claim 4 , wherein each anchor station comprises at least two steerable directional antennas respectively associated with two chains for emitting and receiving frequency-multiplexed signals, able to be pointed respectively towards two consecutive satellites of the constellation and to serve one or more user cells simultaneously by way of one or of two consecutive satellites of the constellation.

6 . The satellite communication system according to claim 5 , wherein each user terminal comprises at least one directional antenna associated with at least one chain for emitting and receiving a radiofrequency signal over bidirectional radiofrequency linkups established by one or two anchor stations with one or two satellites of the constellation.

7 . The satellite communication system according to claim 6 , wherein each satellite of the constellation comprises two steerable directional antennas associated with chains for emitting and receiving radiofrequency signals for relaying radiofrequency links established by two different anchor stations towards user cells and switching means able to activate or interrupt one or more radiofrequency links established by one or the other of the two anchor stations with the user cells.

8 . The satellite communication system according to claim 7 , comprising at least two anchor stations situated inside or outside the coverage area.

9 . The satellite communication system according to claim 1 , comprising two coverage areas covering the two polar regions, arctic and antarctic, a constellation of satellites placed in elliptical orbit around the Earth, in a single orbital plane inclined by an angle of between 60° and 90° with respect to the terrestrial equatorial plane, the satellites being distributed around the Earth at an altitude of less than or equal to 20000 km, user terminals located within the two coverage areas consisting of the two polar regions at the latitudes of respectively greater than +60° and less than −60°, and at least one anchor station per polar regions.

10 . The satellite communication system according to claim 1 , comprising a coverage area including at least one of the two polar regions, arctic and antarctic, a constellation of satellites placed in elliptical orbit around the Earth, in several orbital planes equi-distant from one another and inclined by an angle of between 60° and 90° with respect to the terrestrial equatorial plane, the satellites being distributed around the Earth at an altitude of less than or equal to 20000 km, user terminals located in the coverage area, and a set of anchor stations distributed within or beyond the polar regions.

11 . The satellite communication system according to claim 1 , wherein the constellation is placed on circular orbit plane(s) to provide service over a coverage area including one of the two polar regions, arctic and antarctic and the handovers of the communications are carried out successively over time between the satellites and/or between the anchor stations, the satellites being equi-distributed around the Earth at an altitude of less than or equal to 20000 km.

Assignees

• Thales Sa

Inventors

• Chuberre Nicolas
• Cote Judith
• Bruniera Jean-Jacques
• Benard Patrick
• Potuaud Dominique

Classifications

• H04W36/0011 Primary

  for data sessions of end-to-end connection · CPC title

• H04B7/18517

  Transmission equipment in earth stations · CPC title

• H04B7/18515

  Transmission equipment in satellites or space-based relays · CPC title

• H04B7/19

  Earth-synchronous stations · CPC title

• H04W84/06

  Airborne or Satellite Networks (space-based or airborne stations H04B7/185) · CPC title