Single-point locating system

• US 4,819,053 A
• Filed: 04/17/1987
• Issued: 04/04/1989
• Est. Priority Date: 05/09/1986
• Status: Expired due to Fees

• Current Assignee: Energetics, Inc. (Maryland) (VSE Corporation)
• Original Assignee: Energetics, Inc. (Maryland) (VSE Corporation)
• Inventors: Halavais, Richard A.
• Primary Examiner(s): Blum, Theodore M.
• Assistant Examiner(s): Hellner, Mark
• Application Number:
  US07/039,973
• Time in Patent Office: 718 Days
• Field of Search: 342/353, 342/354, 342/355, 342/356, 342/357, 342/157, 342/158, 342/457
• US Class Current: 342/353
• CPC Class Codes: G01S 2205/06 Emergency
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G01S 5/02 using radio waves using satellite radio beacon systems for determining position G01S19/00

Abstract

A locating system employs a single-point device employing unique scanning patterns for generating peak signal data which can be used to calculate the position of a signal source within a scanned region. One preferred embodiment utilizes a satellite in high earth geosynchronous orbit and a simultaneous yaw and roll pattern to scan a substantial portion of the earth'"'"'s surface. The point source being located may be virtually any form of transmitter of radiant energy such as infrared, electromagnetic, light or acoustical energy. The scanning device may also be positioned in a low earth orbit satellite, an aircraft, a missile or a helicopter. The single-point device re-radiates the signal source transmission to a computer command center which correlates single-point device scanning position data with received transmissions to accurately compute the location of the signal source. Beacons placed at precisely known locations may be used to interpret scan data. The computer triangulates peak signals of multiple roll orbits generated during each yaw orbit of the single-point device to determine the precise location of the source. The computer may also search a data base to identify the signal source and provide related information previously stored in the data base. The invention is particularly advantageous for locating stolen vehicles and for finding kidnapped persons. The system may also be used for determining altitude of a signal source that may, for example, be located on an aircraft in flight.

Claims

1. A locating system comprising:

a source of radiation the position of which in a scanned region is to be determined;

a relay device having means for scanning said region in a prescribed pattern, said pattern being the composite of a first circular path over said region and a plurality of second circular paths, said second circular paths being smaller than and spaced symmetrically along said first circular path, and means for determining the directions of respective straight lines between said source of radiation and one point on at least two of said second circular paths whereby the position of said source of radiation in said scanned region is determined by the intersection of said straight lines.

2. The locating system recited in claim 1 wherein said relay device comprises means for relaying a manifestation of the radiation of said source of radiation to said determining means.

3. The locating system recited in claim 2 wherein said determining means comprises a peak radiation detector and means for ascertaining from detection of peak radiation from said source of radiation, the point on each of said scanning second circular paths at which such peak radiation detection occurs.

4. The locating system recited in claim 3 wherein said radiation is electromagnetic.

5. The locating system recited in claim 3 wherein said radiation is infrared.

6. The locating system recited in claim 3 wherein said source of radiation comprises a radio transmitter.

7. The locating system recited in claim 6 wherein said radio transmitter generates an encoded signal indicative of the identity of the transmitter.

8. The locating system recited in claim 3 wherein said relay device comprises a radiation receiver and a transmitter.

9. The locating system recited in claim 3 wherein said relay device comprises an earth orbiting satellite.

10. The locating system recited in claim 3 wherein said relay device comprises a geosynchronous orbit satellite.

11. The locating system recited in claim 3 wherein said determining means comprises a programmed computer and wherein said locating system further comprises at least one radiation source positioned within said scanned region at a location known precisely by said computer whereby to enable selective calibration of said locating system.

12. The locating system recited in claim 3 wherein said source of radiation comprises means for selective activation in response to a predetermined event.

13. The locating system recited in claim 12 wherein said source of radiation is located in a vehicle and said predetermined event is unauthorized access to said vehicle.

14. The locating system recited in claim 12 wherein said source of radiation is located on a person and said predetermined event is endangerment of such person.

15. The locating system recited in claim 3 further comprising means for communicating the determined position of said source of radiation.

16. The locating system recited in claim 9 wherein said relay device further comprises an additional satellite for downlink communication with said determining means.

26. The locating system recited in claim 1 further comprising means for determining the position of said source of radiation in three dimensions.

27. The locating system recited in claim 1 further comprising means for determining the altitude of said source of radiation.

17. A system for ascertaining the location of an energy-radiating source within a defined geometrical area on the surface of the earth;

the system comprising;

an orbiting satellite positioned above said area, said satellite having means for detecting said radiation energy, means for scanning said area in a selected pattern, and means for re-radiating said radiant energy;

said selected pattern comprising a composite of a first arcuate path over said area and a plurality of second arcuate paths along said first arcuate path; and

an earth-based receiving apparatus having means for receiving said re-radiated radiant energy, means for ascertaining the direction of peak radiation from said source relative to a point on each such second arcuate path at which said scanning means is scanning respectively, when such peak radiation is detected by said detecting means, and means for calculating the intersection of said directions for locating said source.

18. The system recited in claim 17 wherein said scanning means comprises a narrow width antenna the main beam of which is directed toward said geometrical area and continuously moved in said selected pattern.

19. The system recited in claim 18 wherein said main beam is continuously moved by corresponding motion of said satellite.

20. The system recited in claim 19 wherein said motion of said satellite comprises approximately one revolution per minute in yaw to generate said first arcuate path and approximately twelve revolutions per minute in roll to generate said second arcuate paths.

21. The system recited in claim 18 wherein said main beam is continuously moved for scanning along said first arcuate path by corresponding motion of said satellite.

22. The system recited in claim 21 wherein said main beam is continuously moved for scanning along said second arcuate paths by mechanical roll motion of said antenna.

23. The system recited in claim 17 wherein said scanning means comprises an elongated longitudinal array of narrow beamwidth antennas forming an elongated, narrow scanning beam.

24. The system recited in claim 17 wherein said scanning means comprises an elongated longitudinal array of infrared detection devices.

28. The system recited in claim 17 further comprising means for determining the position of said source in three dimensions.

29. The system recited in claim 17 further comprising means for determining the altitude of said source.

25. A system for determining the precise physical location of a receiver within a defined geometrical area on the surface of the earth;

the system comprising;

an orbiting satellite positioned above said area, said satellite having means for scanning said area in a selected pattern while simultaneously transmitting a signal indicative of its instantaneous scan direction, said selected pattern comprising a composite of a first arcuate path over said area and a plurality of second arcuate paths along said first arcuate path; and

a receiver for receiving said signal and means for ascertaining the direction of peak signal strength and correlating said directions with said scan direction relative to a point on each such second arcuate path, respectively, for calculating the intersection of said directions for locating said receiver within said area.