Elliptical orbit satellite, system, and deployment with controllable coverage characteristics

• US 5,669,585 A
• Filed: 11/19/1996
• Issued: 09/23/1997
• Est. Priority Date: 06/02/1992
• Status: Expired due to Fees

• Current Assignee: ESBH, Inc.
• Original Assignee: Mobile Communications, Inc.
• Inventors: Draim, John E., Brosius, Jay, Castiel, David
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): MARQUIS, LISSI MOJICA
• Application Number:
  US08/746,911
• Time in Patent Office: 308 Days
• Field of Search: 244/63, 244/458 R, 244/164, 342/355, 342/356, 342/357, 342/358, 455/12.1, 455/13.1
• US Class Current: 244/158.4
• CPC Class Codes: B64G 1/002 Launch systems
• 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 1/2423 Sun-synchronous orbits
• 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 7/195 Non-synchronous stations

Abstract

A special set of elliptical satellite orbits are described which allow preferential coverage of one parameter over another. According to a first modification, the orbits are retrograde, and preferentially cover one geographical location or time of day as compared with another. A second modification uses prograde orbits and allows the apogee of the orbit to be offset a constant amount with respect to the sun, to thereby cover a different time of day relative to the others. According to a special preferred mode of the invention, the apogee is always pointing towards the sun.

Claims

1. A satellite in orbit around the earth, defining an elliptical orbit which has orbital parameters to satisfy the equation ##EQU10## where Ω

is the right ascension of the ascending node, and ω

is the argument of perigee, and wherein said satellite in orbit asymmetrically covers one parameter of coverage preferentially over another in a way which is constant relative to the sun, all year round.

2. A satellite as in claim 1, wherein said parameter of coverage is geographical location.

3. A satellite as in claim 1, wherein said parameter of coverage is time of day.

4. A satellite as in claim 2, wherein said elliptical orbit is retrograde.

5. A satellite as in claim 3, wherein said elliptical orbit is prograde.

6. A satellite as in claim 4, wherein said orbit is chosen such that ##EQU11## approaches zero.

7. A satellite as in claim 6, wherein an inclination of said orbit is set to substantially 116°

.

8. A satellite as in claim 6, wherein an inclination of said orbit is set to between substantially 115°

and 118°

.

9. A satellite as in claim 1, having a period of three hours.

10. A satellite as in claim 8, wherein period varies from 2.6 to 3.0 hours, apogee varies from 200 to 400 nautical miles, and perigee varies from 2200 to 400 nautical miles.

11. A satellite as in claim 8, having orbital periods between 2.68 and 3.05 hours, and orbital eccentricities between 0.002 and 0.371.

12. A satellite as in claim 5, wherein the apogee is always at a constant angle from the earth-sun line:

an inclination is between 0 and 43 degrees, period is between 1.7 to 5.0 hours, and eccentricity is between 0.0002 to 0.56.

13. A satellite as in claim 5, wherein inclination is greater than 0.5°

, but less than 43°

.

14. A satellite as in claim 5, wherein inclination is greater than 10°

, but less than 43°

.

15. A satellite in orbit as in claim 1, wherein said orbit is inclined.

22. A satellite in orbit as in claim 1, wherein an ascending node of the satellite is either at noon or at midnight.

16. A satellite in orbit around the earth, defining an elliptical, retrograde orbit in which ##EQU12## where Ω

is the right ascension of the ascending node and ω

is the argument of perigee, and wherein an inclination of the orbit is set in a range between 115° and

118°

.

17. A satellite in orbit around the earth, defining an elliptical orbit which has orbital parameters to satisfy the equation ##EQU13## wherein neither ##EQU14## where Ω

equals the right ascension of the ascending node and ω

is the argument of perigee and wherein said orbit is prograde and said satellite in orbit asymmetrically covers one parameter of coverage, preferentially over another in a way which is constant relative to the sun, all year round.

18. A satellite in orbit as in claim 17, wherein said orbit is inclined.

19. A satellite in orbit as in claim 18, wherein said inclination is 10°

or greater.

20. A satellite in orbit as in claim 17, wherein a period of the orbit is three hours.

21. A satellite in orbit as in claim 17, wherein an apogee of said orbit is always pointing towards the sun, all year round.

23. A method of orbiting a satellite around the earth, comprising the steps of obtaining a satellite, and propelling said satellite into an elliptical orbit which has orbital parameters to satisfy the equation ##EQU15## where Ω

is the right ascension of the ascending node, and ω

is the argument of perigee, and wherein said orbit has characteristics to asymmetrically cover one parameter of coverage preferentially over another in a way which is constant relative to the sun, all year round.

24. A method as in claim 23, wherein said propelling step includes propelling in a retrograde direction, said one parameter includes at least geographical location, and orbit is defined such that ##EQU16## approaches zero.

25. A method as in claim 24, wherein said propelling step includes propelling said satellite into an orbit which has an inclination substantially between 115°

and 118°

.

26. A method as in claim 23, wherein said propelling step includes propelling in a prograde direction, said one parameter includes at least time of day, and orbit is defined such that ##EQU17## is not zero.

27. A method as in claim 26, wherein said propelling step includes propelling said satellite into an orbit whose inclination is greater than 0.5°

, but less than 43°

.

28. A method as in claim 26, wherein said propelling step includes propelling said satellite into an orbit whose inclination is greater than 10°

, but less than 43°

.

29. A constellation of satellites in orbit around the earth, each defining an elliptical orbit which has orbital parameters to satisfy the equation ##EQU18## where Ω

is the right ascension of the ascending node, and ω

is the argument of perigee, and wherein each of said satellites in orbit asymmetrically covers one parameter of coverage preferentially over another in a way which is constant relative to the sun, all year round.

30. A constellation of satellites as in claim 29, wherein said parameter of coverage is geographical location.

31. A constellation of satellites as in claim 30, wherein said elliptical orbit is retrograde.

32. A constellation of satellites as in claim 31, wherein said orbit is chosen such that ##EQU19## approaches zero.

33. A constellation of satellites as in claim 32, wherein an inclination of said orbit is set to substantially 116°

.

34. A constellation of satellites as in claim 32, wherein an inclination of said orbit is set to substantially 115°

and 118°

.

35. A constellation of satellites as in claim 29, wherein said parameter of coverage is time of day.

36. A constellation of satellites as in claim 35, wherein each said elliptical orbit is prograde.

37. A constellation of satellites as in claim 29, wherein each satellite has a period of three hours.

38. A constellation of satellites as in claim 36, wherein the apogee is always at a constant angle from the earth-sun line:

an inclination is between 0 and 43 degrees, period is between 1.7 to 5.0 hours, and eccentricity is between 0.0002 to 0.56.

39. A constellation of satellites as in claim 35, wherein inclination is greater than 0.5°

.

40. A constellation of satellites as in claim 35, wherein inclination is greater than 10°

.

41. A constellation of satellites as in claim 36, wherein said orbit is inclined.

42. A constellation of satellites as in claim 29, wherein an ascending node of each of the satellites is either at noon or at midnight.

43. A constellation of satellites as in claim 29, wherein said constellation includes a first ring of satellites, each of which have noon ascending nodes, and a second ring of satellites, each of which have midnight ascending nodes.

44. A rocket and satellites, combination comprising:

a first part, including a rocket which includes boosters for boosting a satellite into orbit, and a inertial guidance unit, said inertial guidance unit including means for propelling said satellite into an elliptical orbit which has orbital parameters to satisfy the equation ##EQU20## where Ω

is the right ascension of the ascending node, and ω

is the argument of perigee, and wherein said orbit has characteristics to asymmetrically cover one parameter of coverage preferentially over another in a way which is constant relative to the sun, all year round and a satellite in said rocket, said rocket also including means for releasing said satellite into said orbit.

45. A combination as in claim 44, wherein said parameter of coverage is geographical location.

46. A combination as in claim 45, wherein said elliptical orbit is retrograde.

47. A combination as in claim 46, wherein said orbit is chosen such that dω

/dt approaches zero.

48. A combination as in claim 44, wherein said parameter of coverage is time of day.

49. A combination as in claim 48, wherein said elliptical orbit is prograde.