Fixed satellite constellation system employing non-geostationary satellites in sub-geosynchronous elliptical orbits with common ground tracks

• US 6,954,613 B1
• Filed: 09/08/2000
• Issued: 10/11/2005
• Est. Priority Date: 09/10/1999
• Status: Expired due to Fees

• Current Assignee: Virtual Satellite Corporation
• Original Assignee: Virtual Geosatellite Holdings, Inc.
• Inventors: Anderson, Jack, Castiel, David, Draim, John E.
• Primary Examiner(s): Hudspeth, David
• Assistant Examiner(s): Afshar, Kamran
• Application Number:
  US09/658,215
• Time in Patent Office: 1,859 Days
• Field of Search: 455/428, 455/429, 455/12.1, 455/13.1, 455/13.2, 342/356, 342/357.06, 342/357.12, 370/321, 370/331
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/195 Non-synchronous stations
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Shows orbit-constellation of satellites that appears virtually geosynchronous.

Claims

1. A satellite system, comprising:

a plurality of satellites in inclined elliptical orbits, each said satellite communicating with a portion of the Earth, at least a first group of said satellites being in common orbits having the same, first, repeating ground track, and a second group of said satellites being in common orbits having the same, second, repeating ground track, different than said first ground track, each said satellite communicating during only a portion of the elliptical orbit closest to apogee;

wherein each of said first and second ground tracks define active portions closest to apogee that follow populated portions on the earth; and

a third group of said satellites being in common orbits having the same, third ground track, different than said first and second ground tracks.

2. A constellation as in claim 1, wherein said first and second ground tracks are in the Northern Hemisphere, and said third ground track is in the Southern Hemisphere.

3. A communication system, comprising:

a plurality of ground stations, each including communication equipment for communicating with a satellite in orbit; and

a plurality of satellites in respective orbits, said respective orbits including a first sub-constellation orbit with a plurality of satellites therein, each of said plurality of satellites following a repeating ground track that repeats an integral number of times each day and each repeating ground track optimized for covering more than one specific land mass on the earth, including a first sub-constellation optimized for covering first land masses in the Northern Hemisphere, a second sub-constellation optimized for covering second land masses in the Northern Hemisphere, and a third sub-constellation optimized for covering third land masses in the Southern Hemisphere.

4. A constellation as in claim 3 wherein each of said sub-constellations has 5 satellites therein.

5. A communication system, comprising:

a plurality of ground stations on respective land masses; and

a plurality of satellites in elliptical orbits, said plurality of satellites being in orbits in sub-constellations, each sub-constellation having a plurality of satellites and repeating ground tracks, which repeating ground tracks are each optimized to follow a plurality of said land masses each satellite operating only during a predetermined percentage of its orbit closest to its apogee, where two of said sub-constellations cover land masses in the Northern Hemisphere and a third sub-constellation covers land masses in the Southern Hemisphere.

6. A constellation as in claim 5 wherein a first sub-constellation has ground tracks covering with apogees covering Alaska, Western United States, Western Canada, Western Europe, West Africa, China and India, a second sub-constellation has ground tracks covering with apogees covering Eastern United States, Canada, Central America, Eastern Europe, Africa, India and China, and the third sub-constellations with apogees covering South America, South Africa, Australia and New Zealand.

7. A constellation as in claim 6 wherein said satellites transmit only during 60 percent of their orbit.

8. A constellation as in claim 5 wherein said satellites are in 8 hour orbits and communicate for 2.4 hours on either side of their apogees.

9. A constellation as in claim 5 wherein said satellites are approximately ¾

of the height necessary for geosynchronous orbit or less.