Optical communication system using a high altitude tethered ballon

• US 20020167702A1
• Filed: 07/03/2002
• Published: 11/14/2002
• Est. Priority Date: 01/10/2000
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Goldfinger, Andrew D., Jerardi, Thomas W., Badesha, Surjit S.
• Granted Patent: US 7,046,934 B2
• Time in Patent Office: Days
• US Class Current: 398/121
• CPC Class Codes: B64B 1/50 Captive balloons
• CPC Class Codes: B64B 1/60 Gas-bags surrounded by separate containers of inert gas
• CPC Class Codes: B64G 1/1007 Communications satellites
• CPC Class Codes: B64G 1/66 Arrangements or adaptations of apparatus or instruments, not otherwise provided for
• CPC Class Codes: B64G 5/00 Ground equipment for vehicles, e.g. starting towers, fuelling arrangements B64G3/00 takes precedence
• CPC Class Codes: H04B 10/118 specially adapted for satellite communication
• CPC Class Codes: H04B 7/18504 Aircraft used as relay or high altitude atmospheric platform

Abstract

An optical communication system using a high altitude tethered balloon 10 that operates above most clouds and atmospheric turbulence. An optical communication system includes a balloon 10 with an optical communication payload 30, a fiber optic cable attached to the tether 12, an automated winch system 14, and a ground station 28. The balloon 10 is designed for sustained flight at, and recovery from, high altitude using the automated winch system 14. An acquisition, tracking and pointing (ATP) system 22 enables a balloon-based optical transceiver 24 to maintain line-of-sight optical communications with an overhead satellite 34. The optical link between the satellite 34 and the balloon 10 is an open channel. Data is transmitted to the ground station 28 from the balloon 10 through the secure fiber optic closed channel attached to the tether 12.

Claims

1. An optical communication system for achieving a clear optical path between earth and a spacecraft with minimal atmospheric disturbances, comprising:

a ground station;

a high altitude balloon system, said balloon system including;

a balloon;

an automated winch near said ground station and operatively connected to said balloon for launching and recovering said balloon; and

a tether extending from said winch to said balloon;

a transceiver attached to said balloon for transmitting or receiving optical data to and from the spacecraft;

an acquisition, tracking and pointing system attached to said balloon for locating the spacecraft, said acquisition, tracking and pointing system using “

blob coloring”

for aligning said transceiver with the spacecraft, enabling open channel optical communication between said balloon and the spacecraft; and

a fiber optic cable attached to said tether and extending from said balloon to said ground station, enabling closed channel optical communication between said balloon and said ground station.

2. An optical communication system as recited in claim 1, wherein said fiber optic cable is embedded in said tether.

3. An optical communication system as recited in claim 1, wherein said tether is tapered between said balloon and said winch.

4. An optical communication system as recited in claim 1, wherein said balloon is spherical in shape.

5. An optical communication system as recited in claim 1, wherein said balloon is operated at an altitude between 12 and 21 km.

6. An optical communication system as recited in claim 1, wherein said high altitude balloon system further comprises:

a ballonet; and

a pressurization system operatively connected to said ballonet for filling and exhausting said ballonet.

7. An optical communication system as recited in claim 1, wherein the spacecraft is a satellite.

8. An optical communication system as recited in claim 7, wherein said acquisition, tracking and pointing system comprises;

a telescope;

means for determining a coarse line of sight from said balloon to the satellite; and

a gimbal, operatively connected to said telescope and to said means for determining said coarse line of sight, for aligning said telescope with said coarse line of sight from said balloon to the satellite.

9. An optical communication system as recited in claim 8, wherein said acquisition, tracking and pointing system further comprises a differential GPS system for determining a coarse attitude of said balloon relative to earth fixed coordinates.

10. An optical communication system for achieving a clear optical path between earth and a spacecraft with minimal atmospheric disturbances, comprising:

a ground station;

a high altitude tethered balloon operatively connected to said ground station;

means operatively connected to said balloon for transmitting optical data between said balloon and the spacecraft;

means operatively connected to said balloon for aligning said means for transmitting optical data between said balloon and the spacecraft; and

means operatively connected to said balloon and said ground station for transmitting optical data between said balloon and said ground station.