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Method and system for controlling the eccentricity of a near-circular orbit

Imported: 24 Feb '17 | Published: 06 Jan '04

Glenn E. Peterson

USPTO - Utility Patents

Abstract

A method and system for controlling the eccentricity of a near-circular orbit are embodied in a burn controller for an orbiting object (such as a satellite) that is configured to control burns to occur at either an apogee or a perigee of the orbit to effect a desired change in the eccentricity of the orbit. These burns occur at either an apogee or a perigee of the orbit depending upon the satellite's location in the long-period motion of the argument of perigee.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed description of embodiments of the invention will be made with reference to the accompanying drawings:

FIG. 1 illustrates an orbiting object, a satellite, in a frozen low earth orbit (LEO);

FIG. 2A illustrates a non-frozen orbit;

FIG. 2B illustrates a frozen orbit;

FIGS. 3A-3C illustrate eccentricity vectors for non-frozen, frozen and ideally frozen orbits, respectively;

FIGS. 4A and 4B illustrate eccentricity vector motion for frozen and non-frozen orbits, respectively;

FIG. 5 illustrates eccentricity vector change;

FIGS. 6A and 6B illustrate eccentricity vectors before and after burn, respectively;

FIG. 7 is an flow diagram of an exemplary bum controller according to the present invention; and

FIG. 8 illustrates an exemplary eccentricity vector control burn scenario according to the present invention.

Claims

1. A method for controlling the eccentricity of a near-circular orbit, comprising:

2. A method for controlling the eccentricity of a near-circular orbit, comprising:

3. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the burns are controlled such that a tolerance on eccentricity vector motion is less than a frozen eccentricity of the orbit.

4. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the burns are controlled to be along-track with respect to the orbit.

5. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the burns are controlled to be transverse to a radius of the orbit.

6. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the burns are controlled such that a magnitude of the eccentricity changes, but not its direction.

7. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the burns are controlled to maintain a semi-major axis.

8. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the burns are controlled to both counteract effects of drag and to drive the eccentricity to the frozen value.

9. The method for controlling the eccentricity of a near-circular orbit of claim 8, Wherein the burns are controlled such that no additional fuel beyond a normal drag compensation fuel budget is required to drive the eccentricity.

10. The method for controlling the eccentricity of a near-circular orbit of claim 2, wherein the object comprises a satellite.

11. A system for controlling the eccentricity of a near-circular orbit, comprising:

12. The system for controlling the eccentricity of a near-circular orbit of claim 11, wherein the controller is configured to control the burns to be along-track with respect to the orbit.

13. The system for controlling the eccentricity of a near-circular orbit of claim 11, wherein the controller is configured to control the burns to be transverse to a radius of the orbit.

14. The system for controlling the eccentricity of a near-circular orbit of claim 11, wherein the controller is configured to control the burns such that a magnitude of the eccentricity changes, but not its direction.

15. The system for controlling the eccentricity of a near-circular orbit of claim 11, wherein the controller is configured to control the burns to maintain a semi-major axis.

16. The system for controlling the eccentricity of a near-circular orbit of claim 11, wherein the controller operates under control of a stationkeeping algorithm that controls the burns to both counteract effects of drag and to drive the eccentricity to the frozen value.

17. The system for controlling the eccentricity of a near-circular orbit of claim 16, wherein the stationkeeping algorithm controls the burns such that no additional fuel beyond a normal drag compensation fuel budget is required to drive the eccentricity.

18. The system for controlling the eccentricity of a near-circular orbit of claim 11, wherein the object comprises a satellite.