Technique for satellite constellation growth

• US 6,491,257 B1
• Filed: 10/13/1999
• Issued: 12/10/2002
• Est. Priority Date: 10/13/1999
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Torkington, Richard Scott, Klekotka, James Edmund, Emmons, Thomas Peter Jr.
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/417,062
• Time in Patent Office: 1,154 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/427, 455/430, 455/431, 455/429, 455/428, 342/352-354, 342/355, 342/356-357, 342/357.07, 342/357.08, 342/357.11, 342/357.16, 342/357.17, 342/359, 342/360, 701/13, 701/226, 244/158.R
• US Class Current: 244/158.6
• 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: H04B 7/19 Earth-synchronous stations

Abstract

Due to the large up front cost in fielding a full capacity satellite constellation (100), it is desirable to have the ability to modify the constellation after deployment to add more capacity in a fashion that does not interrupt service, in order to satisfy a variable or growing market demand. In a satellite constellation including a plurality of orbital planes, each of the orbital planes precesses at a known rate. This invention employs deliberate dynamic manipulation of the orbital precession rates for different satellite planes to increase the separation distance between two adjacent planes. A new plane is then inserted between the two adjacent planes to increase the number of planes and increase the capacity. By continuing a gradual variation, a new orbital plane can be added periodically, e.g. once a year, and the variation can be stopped when no additional orbital planes are desired.

Claims

1. In conjunction with a satellite constellation including a plurality of satellites in a plurality of orbital planes with each of the orbital planes precessing at a precession rate, a method of inserting a new orbital plane in the satellite constellation comprising the steps of:

determining the precession rate for each of the orbital planes according to W=k(a<sup>−

7/2</sup>)(cos i)(1−

e²)^{31 2}, where k is substantially equal to −

2.06474×

10¹⁴, a is the semi-major axis, e is the eccentricity, and i is the inclination;

varying at least one of the variables a, e, and i to increase a separation distance between two adjacent orbital planes of the plurality of orbital planes; and

inserting a new orbital plane between the two adjacent orbital planes.

2. The method as claimed in claim 1, wherein the step of varying one of the variables a, e, and i includes performing a gradual variation to increase the separation distance over a period of time.

3. The method as claimed in claim 2, wherein the step of varying one of the variables a, e, and i includes gradually varying i, the inclination, to increase the separation distance over a period of time.

4. The method as claimed in claim 3, wherein the step of gradually varying i, the inclination, to increase the separation distance over the period of time includes varying the inclination to provide a relative rate change of at least 0.01 degrees per day.

5. The method as claimed in claim 3, wherein the step of gradually varying i, the inclination, to increase the separation distance over the period of time includes varying the inclination to provide a relative rate change of less than 0.01 degrees per day.

6. The method as claimed in claim 1 wherein the step of varying one of a, e, and i is performed to a different degree on each orbital plane of the plurality of orbital planes.

7. The method as claimed in claim 1 further comprising the step of modifying satellite beam patterns to handle changes to separation distances between planes subsequent to the step of inserting the new orbital plane.

8. The method as claimed in claim 1 further comprising the step of modifying satellite beam patterns to handle changes to separation distances between planes after the step of inserting the new orbital plane.

9. The method as claimed in claim 1 further comprising the step of modifying inter-satellite links to handle changes to separation distances between planes subsequent to the step of inserting the new orbital plane.

10. The method as claimed in claim 1 further comprising the step of modifying inter-satellite links to handle changes to separation distances between planes after the step of inserting the new orbital plane.