Positioning system

• US 20050099891A1
• Filed: 03/22/2002
• Published: 05/12/2005
• Est. Priority Date: 03/22/2001
• Status: Active Grant

• Current Assignee: Nautronix (Holdings) PLC (Proserv (1) Ltd.)
• Original Assignee: L-3 Communications Oceania Ltd. (L3Harris Technologies, Inc.)
• Inventors: Graham, Janet, Protoolis, Harry, Doolan, Phil, Stuart, Ross
• Granted Patent: US 7,379,388 B2
• Time in Patent Office: Days
• US Class Current: 367/118
• CPC Class Codes: G01S 5/18 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205

Abstract

A system to position at least one vessel or object in an aquatic environment including: each vessel or object having a receiver connected thereto; and at least two transmitters; wherein each transmitter transmits a unique signal and the receiver on each vessel or object receives each unique signal and a calculation means determines the position of the vessel or object based on the received signals.

Claims

1. A system to position at least one vessel or object in an aquatic environment including:

each said vessel or object having a respective passive receiver connected thereto;

at least two transmitters located below the surface of said aquatic environment and raised above the bottom of said aquatic environment; and

a location means to determine the position of each said transmitter;

wherein each said transmitter transmits a signal that uniquely identifies each said transmitter and is transmitted independent of a command or interrogation signal, and said receiver on each said vessel or object receives each said signal and a calculation means determines the position of said vessel or object based on the received signals.

2. A system as claimed in claim 1, wherein each said transmitter transmits its signal at predetermined times.

3. A system as claimed in claim 1, wherein said transmitter is a transmitting hydrophone.

4. A system as claimed in claim 1, wherein each said transmitter is attached to a respective housing located at the bottom of the aquatic environment.

5. A system as claimed in claim 4, wherein said transmitter is fixed above the floor of said aquatic environment.

6. A system as claimed in claim 4, wherein said transmitter is attached to a floatation means and is floated above said housing.

7. A system as claimed in claim 6, wherein said location means tracks the position of said flotation means.

8. A system as claimed in claim 6, wherein said location means includes a transmitting hydrophone attached to said a housing, and at least three receiving hydrophones attached to said floatation means.

9. A system as claimed in claim 6, wherein said location means includes a transmitting hydrophone attached to said floatation means, and at least three receiving hydrophones located on said housing.

10. A system as claimed in claim 1, wherein at predetermined intervals one of said transmitters will suspend transmission in order to receive a transmission from another said transmitter to enable clock signals of said transmitters to be calibrated or synchronised.

11. A system as claimed in claim 1, wherein said receiver includes a beam former to minimise interference from any noise emanating from said vessel or object to which said receiver is connected.

12. A system as claimed in claim 1, further including a display means for displaying position information.

13. A system as claimed in claim 4, wherein said housing is connected to an external power source.

14. A system as claimed in claim 1 wherein said transmitters are arranged in a hexagonal, square, diamond, octagonal or triangular shaped grid.

15. A system as claimed in claim 1, wherein said transmitters are spaced apart by a distance equal to or greater than the depth of the aquatic environment.

16. A system as claimed in claim 1, wherein said transmitters are located at least 2 km apart.

17. A system as claimed in claim 4, wherein said housing includes:

a main controller for controlling components in said housing;

a signal processing means for modifying any signals transmitted or received;

a power source to provide power to said housing; and

a signal generator to generate said unique signal.

18. A system as claimed in claim 1, wherein said receiver includes:

at least one receiving hydrophone for receiving said unique signals;

a beam former to minimise interference to signals; and

a processing means for controlling components in said receiver.

19. A system as claimed in claim 18, wherein said processing means displays the location on a display unit.

20. A system as claimed in claim 1, further including a stationary reference receiver to assist in the locating and positioning of said object.

21. (canceled)