Solar dominated satellite constellations capable of having repeating common ground tracks
AssigneeNorthrop Grumman Corporation
InventorJohn H. Murphy
Life of this patent
Estimating the term…
Abstract
A new method of constellation design based on combining repeating ground tracks with common ground tracks and/or sun-synchronous orbits is used for performing high-precision change detection imagery for longer periods of time while minimizing battery usage. By precisely prescribing the orbital parameters, sharpened change detection images may be taken without the need to process out blurring by any special image re-working software. The relationship between the orbital parameters of the satellites is precisely tuned to the earth's rotation rate for the altitude of the satellites. The unique set of earth orbits minimizes satellite battery requirement while optimizing the ability to perform coherent change detection (CCD).
Claims28
A constellation of satellites having a repeating common ground track for providing change detection, comprising:
- N satellites configured in a constellation for providing a minimal number of distinctive ground traces represented by k, where N is a integer ≧2, said N satellites being located in N orbital planes which are arbitrarily spaced around the earth, all of said N satellites trace common ground tracks which repeat at k+1 orbits, wherein k is a function of an altitude and an inclination of the N satellites, whereby for particular combinations of altitudes and inclinations a daily repeating common ground track is realized,
- wherein a right ascension of ascending node for orbital plane N (RAANN) and a phasingN for said N satellites are adjusted by multiples of 2π radians so as to have a ground track that is substantially overlapping the previous satellite's ground track.
A method for designing constellations, comprising:
- providing a constellation of satellites having repeating common ground tracks, by
- configuring N satellites in a constellation, where N is a integer ≧2, said N satellites being located in N orbital planes which are arbitrarily spaced around the earth;
- establishing a minimal number of distinctive ground traces represented by k, all of said N satellites tracing common ground tracks which repeat at k+1 orbits, wherein k is a function of an altitude and an inclination of the N satellites, whereby for particular combinations of altitudes and inclinations a daily repeating common ground track is realized, and
- adjusting a RAANN and a phasingN for said N satellites by multiples of 2π radians so as to have a ground track that is substantially overlapping the previous satellite's ground track.
A constellation of sun-synchronous satellites having a repeating common ground track for providing change detection, comprising:
- N satellites configured in a constellation, where N is a integer ≧2, said N satellites being located in N orbital planes, orbits of the N satellites follow a common ground track and remain in close proximity to the terminator of the earth throughout successive orbits, wherein an appropriate altitude, inclination and right ascension of the ascending node (RAAN) are selected so as to precisely match up the orbiting N satellites with the earth's rotation relative to the sun, wherein the RAAN is maintained in a terminator regions,
- wherein the combination of altitude and inclination of the N satellites is selected from the group consisting of the following table:
- Indep
- Grd
- Altitude
- Inclination
- Tracks
- km
- degrees
- 7
- 5171.037
- 142.209
- 8
- 4183.531
- 125.307
- 9
- 3383.598
- 116.022
- 10
- 2719.860
- 110.53
- 11
- 2158.554
- 105.925
- 12
- 1676.479
- 102.936
- 13
- 1257.107
- 100.700
- 14
- 888.314
- 98.982
- 15
- 560.986
- 97.635
- 16
- 268.125
- 96.560
- 17
- 4.264
- 95.690.
A method for designing constellations, comprising:
- providing a constellation of sun-synchronous satellites having repeating common ground tracks, by
- configuring N satellites in a constellation, where N is a integer ≧2, said N satellites being located in N orbital planes;
- establishing orbits of the N satellites that follow a common ground track and remain in close proximity to the terminator of the earth throughout successive orbits;
- selecting an appropriate altitude, inclination and right ascension of the ascending node (RAAN) so as to precisely match up the orbiting N satellites with the earth's rotation relative to the sun, wherein the RAAN is maintained in a terminator region,
- wherein providing the constellation includes selecting a combination of altitude and inclination for the N satellites from a group consisting of the following table:
- Indep
- Grd
- Altitude
- Inclination
- Tracks
- km
- degrees
- 7
- 5171.037
- 142.209
- 8
- 4183.531
- 125.307
- 9
- 3383.598
- 116.022
- 10
- 2719.860
- 110.53
- 11
- 2158.554
- 105.925
- 12
- 1676.479
- 102.936
- 13
- 1257.107
- 100.700
- 14
- 888.314
- 98.982
- 15
- 560.986
- 97.635
- 16
- 268.125
- 96.560
- 17
- 4.264
- 95.690.
Dependencies are inferred from the claim text.