Method and apparatus for location determination of people or objects

• US 7,636,061 B1
• Filed: 01/28/2006
• Issued: 12/22/2009
• Est. Priority Date: 04/21/2005
• Status: Expired due to Fees

• Current Assignee: Alan Thomas, David Thomas Jewett
• Original Assignee: Alan Thomas, David Thomas Jewett
• Inventors: Thomas, Alan, Jewett, David Thomas
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US11/341,927
• Time in Patent Office: 1,424 Days
• Field of Search: 342/357.06, 342/442, 342/457, 342/463, 342/464, 4554561-4563, 701/207, 701/213, 701/215
• US Class Current: 342/464
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308

Abstract

A system and method for determining the position of people and/or objects, whether mobile or stationary, is presented herein. The system uses fixed and/or portable FM transmitters to transmit synchronized signals. These signals are acquired by a Receiver device which uses the signal timing to perform Time Difference of Arrival calculations to determine the Receiver'"'"'s location. Then, using some arbitrary communications method, such as wireless communications, the Receiver device can forward its location to some arbitrary type of application system.

Claims

1. A position location system, comprising:

a plurality of portable transmitters, each of said plurality of portable transmitters configured for transmitting frequency modulation (FM) signals, wherein each of said transmitted FM signals comprises location information associated with its transmitter;

a synchronizer in communication with each of said plurality of transmitters for locking said FM signal transmissions to a common clock, wherein said common clock comprises a global positioning system (GPS) time clock;

a receiver configured for receiving said FM signals emitted from each of said plurality of portable transmitters; and

a processor in communication with said receiver for calculating a location of said receiver using said location information from each of said plurality of portable transmitters and time differences detected amongst each of said transmitted FM signals.

2. The system of claim 1, wherein said receiver comprises an integral part of some other device.

3. The system of claim 1, wherein said receiver is configured to receive FM signals from at least three portable transmitters.

4. The system of claim 1, wherein each of said portable transmitters is configured for obtaining its location information from an external source.

5. The system of claim 1, wherein when each of said portable transmitters is transported from a current geographic location to a new geographic location, said new geographic location may provide a more accurate location calculation of said receiver.

6. A position location system, comprising:

a plurality of transmitters each transmitter configured for transmitting a frequency modulation (FM) signal, wherein said transmitted FM signal contains location information for said transmitter and when said FM signals are transmitted from each of said plurality of transmitters, a synchronization means is provided for locking each of said FM signal transmissions to a common time clock, wherein said common time clock comprises a global positioning system (GPS) time clock, and wherein each of said plurality of transmitters is portable;

a receiver for receiving said transmitted FM signals and measuring time differences detected amongst said transmitted FM signals;

a transmission means configured for sending said measured time differences and said location information for each of said transmitters; and

a calculator for receiving said measured time differences and said location information for each of said transmitters and configured for calculating a location of said receiver.

7. The system of claim 6, wherein said receiver comprises an integral part of some other apparatus.

8. The system of claim 6, wherein said plurality of transmitters comprises at least three transmitters.

9. The system of claim 6, wherein at least one of said plurality of transmitters is further configured for obtaining location information from an external source.

10. The system of claim 6, wherein at least one of said plurality of transmitters is configured for transportation from a current geographic location to a new geographic location, whereby said new geographic location may provide more accurate location calculation of said receiver.

11. A position location system comprising:

a plurality of transmitters each configured for transmitting a frequency modulation (FM) signal, wherein said transmitted FM signal contains location information of said transmitter and timing information, wherein said timing information comprises a global positioning system (GPS) time clock, and wherein each of said plurality of transmitters is portable;

a receiver configured for receiving each of said transmitted FM signals and measuring time differences detected amongst each of said transmitted FM signals from said timing information; and

a calculation apparatus in communication with said receiver for calculating a location of said receiver.

12. The system of claim 11, wherein said receiver is configured for attachment to an object for which its location may be determined.

13. The system of claim 11, wherein said plurality of transmitters comprises at least three transmitters.

14. The system of claim 11, wherein said timing information comprises timing synchronization from a common clock.

15. The system of claim 11, wherein said timing information and said location information are both derived from external sources.

16. The system of claim 11, wherein said plurality of transmitters are mobile.

17. A method for locating an object, comprising:

receiving FM signals at an object, said FM signals transmitted from at least three transmitters, each of said FM signals locked to a common time clock for transmitting timing information, wherein said timing information comprises a global positioning system (GPS) time clock, and wherein each of said at least three transmitters is portable and each of said FM signals further comprising location information for its associated transmitter; and

calculating a location of said object by using time differences detected amongst said timing information in each of said received FM signals and said location information.

18. A method for locating an object, comprising:

transmitting a frequency modulated (FM) signal from each of at least three transmitters, each of said FM signals comprising location information associated with its associated transmitter and synchronized timing information from a single clock, wherein said single clock comprises a global positioning system (GPS) time clock, and wherein each of said at least three transmitters is portable;

receiving said transmitted FM signals at said object; and

calculating the location of said object from said received FM signals.

19. The method according to claim 18, wherein said location information comprises global positioning satellite (GPS) location information.

20. The method according to claim 18, wherein each of said FM signals further comprises a unique identifier associated with its associated transmitter.

21. The method according to claim 18, wherein said calculating comprises:

calculating a time difference of arrival (TDOA) for each of said received FM signals;

formulating a hyperbolic equation for each pair of said received FM signals to obtain a set of hyperbolic equations; and

solving said set of hyperbolic equations with said TDOA for each of said FM signals to determine said location of said object.

22. A position location system, comprising:

at least three transmitter nodes, each of said at least three transmitter nodes is portable and configured for transmitting a frequency modulated (FM) signal, said FM signal comprising;

location information associated with an associated one of the at least three transmitter nodes;

timing information from a single clock, wherein said single clock comprises a global positioning system (GPS) time clock; and

a unique identifier associated with said transmitter; and

a receiver node configured for receiving said at least three FM signals and determining a location associated with said receiver node from said at least three FM signals.

23. The position location system according to claim 22, further comprising a processor in communication with said receiver node configured for determining said location from said at least three FM signals.

24. The position location system according to claim 23, wherein said processor is further configured to:

calculate a time difference of arrival (TDOA) for each of said at least three received FM signals;

formulate a hyperbolic equation for each pair of said at least three received FM signals to obtain a set of hyperbolic equations; and

solve said set of hyperbolic equations with said TDOA for each of said at least three FM signals to determine said location of said receiver node.