Inclined super-GEO orbit for improved space-surveillance

Patent metadata

Field	Value
Publication number	US-9908640-B2
Application number	US-201514841572-A
Country	US
Kind code	B2
Filing date	Aug 31, 2015
Priority date	Aug 31, 2015
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

Systems, methods, and apparatus for space surveillance are disclosed herein. In one or more embodiments, the disclosed method involves scanning, by at least one sensor on at least one satellite in inclined super-geostationary earth orbit (super-GEO), a raster scan over a field of regard (FOR). In one or more embodiments, the scanning is at a variable rate, which is dependent upon a target dwell time for detecting a target of interest. In at least one embodiment, the target dwell time is a function of a range from at least one sensor to the target of interest and a function of a solar phase angle. In some embodiments, the axis of inclination of the inclined super-GEO is a function of the solar phase angle.

First claim

We claim:

1. A method for space surveillance, the method comprising:
scanning, by at least one sensor on at least one satellite in inclined super-geostationary earth orbit (super-GEO), a raster scan over a field of regard (FOR),
wherein the scanning is at a variable rate, which is dependent upon a target dwell time for detecting a target of interest,
wherein the target dwell time is a function of a characteristic brightness of the target, and
wherein the field of regard (FOR) of the at least one sensor is a function of a geometry between a sun and the at least one satellite and a function of an angle that the at least one satellite is pointing.

2. The method of claim 1 , wherein an axis of inclination of the inclined super-GEO is chosen to minimize performance degradations due to earth exclusions.

3. The method of claim 1 , wherein the target dwell time is further a function of a range from the at least one sensor to the target of interest and a function of a solar phase angle.

4. The method of claim 1 , wherein the raster scan comprises at least one sweep.

5. The method of claim 4 , wherein the at least one sweep is a continuous sweep.

6. The method of claim 1 , wherein the method further comprises, during the scanning, collecting, by the at least one sensor, image frames over time.

7. The method of claim 6 , wherein the image frames overlap.

8. The method of claim 1 , wherein super-GEO is an orbit that has a radius that is larger than a geostationary earth orbit (GEO) radius for a majority of a duration of an orbital cycle.

9. The method of claim 1 , wherein a time required for the raster scan is dependent upon an aperture diameter of the at least one sensor and the target dwell time.

10. The method of claim 9 , wherein the time required for the raster scan is further dependent upon an altitude of the at least one sensor.

11. The method of claim 10 , wherein the time required for the raster scan is further dependent upon an instantaneous field of view (IFOV) of the at least one sensor.

12. The method of claim 6 , wherein the method further comprises comparing a detected brightness level in at least one of the image frames to a detection threshold.

13. The method of claim 12 , wherein the method further comprises determining that the target of interest is present when the detected brightness level in at least one of the image frames exceeds the detection threshold.

14. The method of claim 12 , wherein the method further comprises determining that the target of interest is not present when the detected brightness level in at least one of the image frames does not exceed the detection threshold.

15. The method of claim 1 , wherein when there is two or more of the satellites, the method further comprises at least one of the satellites scanning at least a portion of a desired scan area where at least one of the sensors of at least one of the other satellites has low performance.

16. A system for space surveillance, the system comprising:
at least one satellite in inclined super-geostationary earth orbit (super-GEO); and
at least one sensor, on the at least one satellite, to scan a raster scan over a field of regard (FOR),
wherein the scanning is at a variable rate, which is dependent upon a target dwell time for detecting a target of interest,
wherein the target dwell time is a function of a characteristic brightness of the target, and
wherein the field of regard (FOR) of the at least one sensor is a function of a geometry between a sun and the at least one satellite and a function of an angle that the at least one satellite is pointing.

17. The system of claim 16 , wherein an axis of inclination of the inclined super-GEO is chosen to minimize performance degradations due to earth exclusions.

18. The system of claim 16 , wherein the target dwell time is further a function of a range from the at least one sensor to the target of interest and a function of a solar phase angle.

19. The system of claim 16 , wherein the raster scan comprises at least one sweep.

Assignees

• Boeing Co

Inventors

• Gerwe David R
• Williams Keith R
• Lambert John
• Tarbuck Paul D
• Estrada Edward A

Classifications

• B64G1/1021 Primary

  Earth observation satellites · CPC title

• G06F18/22

  Matching criteria, e.g. proximity measures · CPC title

• G06T7/60

  Analysis of geometric attributes · CPC title

• B64G2001/1028

  Operations & Transport · mapped topic

• G06K9/52

  Physics · mapped topic