Elliptical satellite system which emulates the characteristics of geosynchronous satellites

• US 5,845,206 A
• Filed: 03/24/1995
• Issued: 12/01/1998
• Est. Priority Date: 03/24/1995
• Status: Expired due to Term

• Current Assignee: Virtual Satellite Corporation
• Original Assignee: Virtual Geosatellite Holdings, Inc.
• Inventors: Castiel, David, Draim, John, Manning, Kenneth F.
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/409,808
• Time in Patent Office: 1,348 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.4, 455/18, 455/63, 455/127, 455/427, 455/428, 455/429, 455/430, 342/356
• US Class Current: 455/13.4
• CPC Class Codes: B64G 1/10 Artificial satellites; Systems of such satellites; Interplanetary vehicles space shuttles B64G1/14
• CPC Class Codes: B64G 1/1007 Communications satellites
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64G 1/242 Orbits and trajectories
• CPC Class Codes: B64G 1/428 Power distribution and management
• CPC Class Codes: H04B 7/18576 Satellite systems for providing narrowband data service to fixed or mobile stations, e.g. using a minisatellite, a microsatellite for selecting H04W
• CPC Class Codes: H04B 7/19 Earth-synchronous stations
• CPC Class Codes: H04B 7/195 Non-synchronous stations

Abstract

An elliptical satellite system which carries out communication. The satellite orbits a height above the earth less than that necessary for geosynchronous orbits. When the satellite is near the apogee portion of its orbit, its velocity approximates the rotational velocity of the earth, and during that period it appears to hover over the earth. Each ground station on the earth always communicates with a satellite within a predetermined position of its apogee, and hence that satellite appears to the ground station to hover over the earth. The satellite hence does not communicate with any earth station when it is outside of that apogee portion. During the times when the satellite is outside the apogee portion, its communication is therefore shut off to prevent any possibility of interfering with geosynchronous satellites. During this time, the power supply on the satellite is also used to charge a battery on the satellite. This enables the power supply to be made smaller by an amount equivalent to the duty cycle of the satellite: during the time which it is on.

Claims

1. A ground-to-satellite communication system comprising:

a first ground communication system, including communication equipment therein, located at a first position on the earth;

a second ground communication system including second communications system therein, located at a second position on the earth spaced from the first position;

a plurality of satellites in orbits circling the earth, each satellite always having an orbital height which is lower than a height necessary for geosynchronous orbit, and each said satellite having communications equipment thereon, said communication equipment communicating with said ground stations, said satellites orbiting in elliptical orbits having apogees and perigees, and having ground tracks such that each said ground communication system is always able to track one satellite within a predetermined angular separation from the apogee point of at least one of said satellites,

said first ground communication equipment transmitting information having a volume to one of said satellites which is near its apogee position and which receives said program,

said one satellite including a storage memory thereon, said storage memory storing said program from said first ground communication equipment sent while said first satellite is near its apogee position over said first ground communication equipment, said first satellite thereafter orbiting to a position distant from said apogee position and then terminating said transmission, and thereafter orbiting to an apogee position over said second ground communication equipment, said first satellite communicating said program stored in said storage memory to said second ground communication equipment;

a power supply, having a capacity to produce only an amount of power less than said first amount of power;

a power storage element, connected to said power supply, and operating to store power produced from said power supply which is in excess of that used by said satellite communication equipment; and

a controller, controlling said transmitter and receiver to communicate during only a part of a total time of operation, said power supply and said power storage element together supplying power to said satellite transmitter and receiver when communicating, and said power supply storing power in said power storage element when said satellite transmitter and receiver is not communicating.

2. A satellite communications system, comprising:

a ground station, located at a fixed location on the earth, and including satellite communications equipment and a steerable antenna;

at least three orbiting satellites in elliptical orbits at orbital heights lower than that necessary for geosynchronous, each said satellite including communication equipment therein which operates during only a portion of a time of said orbits, and an antenna, said communication equipment communicating via said antenna, to said antenna in said satellite communications equipment in said ground station, each of said at least three orbiting satellites orbiting in orbits having parameters to form a repeating earth ground track, and said orbits controlled such that said ground station always communicates with one of said satellites while said one satellite is within a predetermined angular separation of an apogee of said orbit, each said satellite including means for determining a position of communication of said one satellite relative to a position of geosynchronous satellites, means for determining an amount of separation between said position of communication and the position of geosynchronous satellites and means for turning off the satellite communications equipment when said separation becomes lower than a predetermined amount.

3. A system as in claim 2 wherein said determining means is an antenna position detecting device.

4. A communications system, comprising:

a ground station including a tracking antenna and tracking electronics to steer the tracking antenna to follow a desired target;

at least three satellites, each in separate elliptical orbits around the earth at altitudes lower than that necessary for geosynchronous orbit, and each said satellite including communications equipment thereon which communicates with said ground station, each satellite orbit such that one focus of each elliptical orbit is the position of the earth, including;

a first satellite which communicates with said ground station at a first time when said first satellite is at a position in its orbit where an orbital angular velocity in the equatorial plane of said first satellite is within a predetermined percentage of a rotational velocity of the earth around its own axis,

a second satellite which communicates with said ground station at a second time where the orbital angular velocity in the equatorial plane of said second satellite is within a predetermined percentage of a rotational velocity of the earth around its own axis, and

a third satellite which communicates with said ground station at a third time where the orbital angular velocity in the equatorial plane of said third satellite is within a predetermined percentage of a rotational velocity of the earth around its own axis.

5. A communication system as in claim 4 wherein said communication with said first, second and third satellites respectively occurs when said satellite and said earth have a rotational velocity which differs by not more than 20%.