Integrated antenna system for imaging microsatellites

• US 8,482,610 B2
• Filed: 08/03/2012
• Issued: 07/09/2013
• Est. Priority Date: 12/15/2010
• Status: Active Grant

• Current Assignee: Planet Labs PBC
• Original Assignee: Skybox Imaging, Inc. (Planet Labs PBC)
• Inventors: do Carmo Miranda, Henrique
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): LUO, KATE H
• Application Number:
  US13/566,548
• Publication Number:
  US 20120300071A1
• Time in Patent Office: 340 Days
• Field of Search: None
• US Class Current: 348/144
• CPC Class Codes: B64G 1/1021 Earth observation satellites
• CPC Class Codes: B64G 1/222 for deploying structures between a stowed and deployed state
• CPC Class Codes: B64G 1/66 Arrangements or adaptations of apparatus or instruments, not otherwise provided for
• CPC Class Codes: H01Q 1/08 Means for collapsing antennas or parts thereof collapsible loop antennas H01Q7/02; means for collapsing H-antennas or Yagi antennas H01Q19/04
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 19/10 using reflecting surfaces
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04N 7/005 using at least one opto-electrical conversion device
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

Examples of imaging microsatellites are described that have an imaging system and antenna system disposed within the microsatellite body when the microsatellite is in a non-deployed state. The properties of the antenna system can be adjusted such that the antenna system does not impact, contact, or displace the imaging system when the microsatellite is in the non-deployed state. The properties of the antenna system can be adjusted such that the antenna system does not contact or impact the body of the microsatellite or any other structure when the microsatellite transitions to a deployed state. The antenna system can be configured to achieve a desired gain and/or data transmission rate by adjusting properties of the antenna system based on the radiation pattern of an antenna feed and geometric constraints imposed by the imaging system. Examples of methods for designing such imaging microsatellites are provided.

Claims

1. An imaging microsatellite having an integrated antenna system, the microsatellite comprising:

a body comprising a plurality of surfaces forming an interior cavity and an opening in the body;

a door attached to at least one of the plurality of surfaces, the door comprising an interior surface and an exterior surface, the door movable from a closed position to an open position, wherein in the closed position the door covers the opening and in the open position the door uncovers the opening;

the integrated antenna system comprising;

an antenna reflector attached to the interior surface of the door;

an antenna feed support attached to the antenna reflector or the door; and

an antenna feed attached to the antenna feed support, wherein the antenna feed support is configured to secure the antenna feed in a fixed position relative to the antenna reflector; and

an imaging system disposed within the interior cavity of the body of the microsatellite, the imaging system configured to image a field of view through the opening when the door is in the open position;

wherein the integrated antenna system is configured to;

fit within the interior cavity without coming into contact with the imaging system when the door is in the closed position; and

move with the door through the opening in an unobstructed manner when the door moves from the closed position to the open position.

2. The microsatellite of claim 1, wherein the microsatellite has a volume that is less than or equal to about 125 cm by 125 cm by 175 cm.

3. The microsatellite of claim 1, wherein the microsatellite has a mass that is less than or equal to about 500 kg.

4. The microsatellite of claim 1, wherein the microsatellite is configured to launch as a secondary payload on a launch vehicle configured to launch a primary payload.

5. The microsatellite of claim 1, wherein a diameter of the antenna reflector is less than or equal to about 120 cm.

6. The microsatellite of claim 1, wherein a diameter of the antenna reflector is greater than or equal to about 30 cm.

7. The microsatellite of claim 1, wherein a ratio of a diameter of the antenna reflector to a width of the door is greater than about 50%.

8. The microsatellite of claim 1, wherein the imaging system comprises a telescope, the telescope comprising:

a primary mirror;

a secondary mirror; and

a secondary mirror support configured to secure the secondary mirror in a fixed position relative to the primary mirror.

9. The microsatellite of claim 8, wherein the antenna feed is disposed between the primary mirror and the secondary mirror when the door is in the closed position.

10. The microsatellite of claim 8, wherein the imaging system further comprises:

a primary baffle associated with the primary mirror; and

a secondary baffle associated with the secondary mirror.

11. The microsatellite of claim 10, wherein the antenna feed is disposed between the primary baffle and the secondary baffle when the door is in the closed position.

12. The microsatellite of claim 8, wherein the secondary mirror support comprises a plurality of support struts, and the antenna feed support extends between two adjacent struts when the door is in the closed position.

13. The microsatellite of claim 1, further comprising a release mechanism configured to secure the door to the body when the door is in the closed state, the release mechanism actuatable to release the door and allow the door to move from the closed state to the open state.

14. The microsatellite of claim 13, further comprising an opening mechanism configured to move the door from the closed position to the open position when the release mechanism is actuated.

15. The microsatellite of claim 1 wherein the antenna system is configured to provide a gain greater than or equal to 25 dBi.

16. The microsatellite of claim 1 wherein the antenna system is configured to provide a data transmission rate between about 1 Mbit/s and 100 Mbit/s.

17. The microsatellite of claim 1, wherein the antenna reflector has a diameter d and focal length f, and a ratio f/d matches a radiation pattern of the antenna feed.