Message transmission system

• US 5,142,399 A
• Filed: 11/30/1990
• Issued: 08/25/1992
• Est. Priority Date: 12/01/1989
• Status: Expired due to Term

• Current Assignee: Sat Societe Anonyme de Telecommunications Societe Anonyme Francaise
• Original Assignee: Societe Anonyme de Telecommunications (Safran SA)
• Inventors: Castanet, Yves R., Bertrand, Michel P., Bucher, Michel B. J.
• Primary Examiner(s): Coles, Jr., Edward L.
• Assistant Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US07/621,230
• Time in Patent Office: 634 Days
• Field of Search: 455/617, 455/618, 455/619, 455/607, 356/152, 356/141, 356/138, 280/551, 280/332, 280/206.2, 359/154, 359/159, 244/114 R
• US Class Current: 398/131
• CPC Class Codes: H04B 10/1143 Bidirectional transmission

Abstract

A message transmission system is operative for transmitting, over a short range, information emitted by at least one transmitter to one or more receivers, the transmitter being situated in a semi-hemispherical field above the receivers. Each receiver has optics for focusing the semi-hemispherical field on multiple detector elements of an array placed in the focal plane of the optics. The elements are responsive to the transmitted signal.

Claims

1. An outdoor, short-range communications system, comprising:

transmitter means on a support, and operative for generating a modulated light beam encoded with a message, and for transmitting the light beam away from the support; and

receiver means spaced from the transmitter means away from the support, and operative for receiving the transmitted beam to decode the message, said receiver means including a wide-angle, substantially hemispherical objective lens system having a focal plane and a generally circular field of view covering an angular distance of ±

90°

in elevation, and photosensor means at said focal plane for omnidirectionally detecting the transmitted beam through the objective lens system over the entire field of view thereof.

2. The communications system according to claim 1, wherein the support is a mast on an aircraft carrier, and wherein the receiver means is mounted onboard an aircraft.

3. The communications system according to claim 2, wherein the aircraft is mounted on a deck of the carrier, and wherein the transmitter means is mounted on the mast to direct the transmitted light beam downwardly toward the deck and outwardly away from the mast.

4. The communications system according to claim 1, wherein the transmitter means includes a light source for emitting the light beam in a predetermined frequency range selected from the group consisting of infrared light frequencies, visible light frequencies, and ultraviolet light frequencies.

5. The communications system according to claim 1, wherein the transmitter means includes a plurality of transmitters mounted on individual, different, spaced-apart masts of an aircraft carrier, and wherein the receiver means includes a plurality of receivers mounted on-board individual, different aircraft.

6. The communications system according to claim 5, wherein the transmitters transmit modulated light beams encoded with the same message.

7. The communications system according to claim 5, wherein the transmitters transmit modulated light beams encoded with different messages.

8. The communications system according to claim 5, wherein the photosensor means includes a plurality of photosensors for generating electrical signals indicative of the transmitted beam incident thereon;

and further comprising means for multiplexing the electrical signals over a pair of adjacent channels, means for amplifying the multiplexed signals from said channels, means for discriminating noise from the amplified signals, means for selecting the amplified signal having the least noise, and means for processing the least noisy amplified signal.

9. The communications system according to claim 1, wherein the objective lens system includes a plurality of lenses mounted within a tube having a dome extending outwardly of an aircraft.

10. The communications system according to claim 1, wherein the photosensor means includes an array of detector elements positioned in said focal plane.

11. The communications system according to claim 10, wherein the detector elements are stationarily positioned in said focal plane.

12. The communications system according to claim 10, wherein the detector elements are turned about an axis generally perpendicular to said focal plane.

13. The communications system according to claim 10, wherein the detector elements are arranged along linear rows and along linear columns.

14. The communications system according to claim 10, wherein the detector elements are located on a rotary plate having a center and an axis of rotation, and are arranged along a single radial strip extending along a radial axis from the center, each detector element having a quadrilateral shape bounded by a pair of radial lines and a pair of boundary lines perpendicular to said radial axis.

15. The communications system according to claim 10, wherein the detector elements are located on a rotary plate having a center and an axis of rotation, and are arranged along a pair of radial strips spaced angularly apart of each other, each radial strip extending along a different radial axis from the center, each detector element having a quadrilateral shape bounded by a pair of radial lines and a pair of boundary lines perpendicular to a respective radial axis, and wherein the detector elements of one of the strips are radially displaced along its radial axis relative to the detector elements of the other of the strips.

16. The communications system according to claim 10, wherein the detector elements are located on a rotary plate having a center and an axis of rotation, and are arranged along a single radial strip extending along a radial axis, each detector element having a quadrilateral shape bounded by a pair of radial lines and a pair of boundary lines inclined relative to said radial axis.

17. The communications system according to claim 10, wherein the detector elements are located on a rotary plate having a center and an axis of rotation, and are arranged along a plurality of radial strips spaced angularly apart of each other, each radial strip extending along a different radial axis from the center, each detector element having a sector shape bounded by a pair of radial lines and a pair of curved boundary lines centered on said center, and wherein the detector elements of one of the strips are radially displaced along its radial axis relative to the detector elements of an adjacent strip.

18. The communications system according to claim 17, wherein the plate is turnable in either circumferential direction about said axis of rotation.

19. The communications system according to claim 10, wherein the detector elements are located on a rotary plate having a center and an axis of rotation, and are arranged along a plurality of radial strips spaced angularly apart of each other, each radial strip extending along a different radial axis from the center, each detector element having a sector shape bounded by a pair of radial lines and a pair of curved boundary lines centered on said center, and wherein the detector elements are arranged in circular loci about said center.