System and method for person or object position location utilizing impulse radio

• US 20080042845A1
• Filed: 10/12/2007
• Published: 02/21/2008
• Est. Priority Date: 03/23/1998
• Status: Active Grant

• Current Assignee: Plus Location Systems Pty. Limited
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Richards, James, Fullerton, Larry, Finn, James, Tucker, William, Payment, Timothy, Meigs, David, Kelly, Donald, Welch, William
• Granted Patent: US 7,474,219 B2
• Time in Patent Office: Days
• US Class Current: 340/572.4
• CPC Class Codes: G01S 1/20 using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0226 Transmitters
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 1/7163 using impulse radio
• CPC Class Codes: H04B 1/7183 Synchronisation
• CPC Class Codes: H04B 2001/6908 using time hopping

Abstract

A System and Method for Person or Object Position Location Utilizing Impulse Radio, comprising a plurality of reference impulse radios; an object or person to be tracked having a mobile impulse radio associated therewith; an architecture with an associated positioning algorithm associated with said plurality of impulse radio reference radios and said mobile impulse radio; and display means for displaying the position of the person or object whose position is to be determined.

Claims

1. An object location system for determining the position of an object, said object location system comprising:

an RF tag to transmit a tag signal, said RF tag being associated with said object;

a plurality of reference radios positioned at known locations, each of said plurality of reference radios being coupled to a common clock source and including a time counting device that is indexed at a higher frequency relative to the frequency of the common clock and frequency-locked with said common clock source to maintain synchronization of each said time counting device, each of said plurality of reference radios including a receiver to receive said tag signal; and

a processor obtaining times of arrival of said tag signal at said plurality of reference radios to determine said position of said object based on said times of arrival and said known locations of said plurality of reference radios.

2. The object location system of claim 1, wherein said processor determines said position of said object using one of a time-of-arrival method, a round trip time-of-flight method, a differential time-of-arrival method, a differenced time-of-arrival method, an angle-of-arrival method, an absolute signal amplitude range determination method, a relative signal amplitude range determination method, a directional antenna-based method, or a beam steering method.

3. The object location system of claim 1, further comprising:

a reference transmitter having a known location to transmit a reference signal, wherein each of said plurality of reference radios also receives said reference signal, wherein said processor also obtains times of arrival of said reference signal and determines said position of said object based on said times of arrival of said reference signal and said known location of said reference transmitter.

4. The object location system of claim 1, wherein said RF tag and said plurality of reference radios comprise ultra wideband technology.

5. The object location system of claim 1, wherein said tag signal comprises low duty cycle pulses.

6. The object location system of claim 5, wherein each of said low duty cycle pulses approaches one cycle per pulse.

7. The object location system of claim 5, wherein each of said low duty cycle pulses consists of a burst of cycles.

8. The object location system of claim 7, wherein said burst of cycles is spectrally shaped to control bandwidth to meet at least one desired property.

9. The object location system of claim 8, wherein said at least one desired property comprises at least one of out of band emissions, in-band spectral flatness, time domain peak power, or burst off time attenuation.

10. The object location system of claim 1, wherein said plurality of reference radios are in communication with each other via wired or wireless means.

11. A method for determining the position of an object, said method comprising the steps of:

associating an RF tag with said object;

transmitting a tag signal from said RF tag;

receiving said tag signal at a plurality of reference radios positioned at known locations, each of said plurality of reference radios being coupled to a common clock source and including a time counting device that is indexed at a higher frequency relative to the frequency of the common clock and frequency-locked with said common clock source to maintain synchronization of each said time counting device, each of said plurality of reference radios comprising a receiver to receive said tag signal;

obtaining times of arrival of said tag signal at said plurality of reference radios; and

determining said position of said object based on said times of arrival and said known locations of said plurality of reference radios.

12. The method of claim 11, wherein said position of said object is determined using one of a time-of-arrival method, a round trip time-of-flight method, a differential time-of-arrival method, a differenced time-of-arrival method, an angle-of-arrival method, an absolute signal amplitude range determination method, a relative signal amplitude range determination method, a directional antenna-based method, or a beam steering method.

13. The method of claim 11, further comprising:

placing a reference transmitter at a known location;

transmitting a reference signal from said reference transmitter;

receiving said reference signal at each of said plurality of reference radios;

obtaining times of arrival of said reference signal; and

determining said position of said object based on said times of arrival of said reference signal and said known location of said reference transmitter.

14. The method of claim 11, wherein said RF tag and said plurality of reference radios comprise ultra wideband technology.

15. The method of claim 11, wherein said tag signal comprises low duty cycle pulses.

16. The method of claim 15, wherein each of said low duty cycle pulses approaches one cycle per pulse.

17. The method of claim 15, wherein each of said low duty cycle pulses consists of a burst of cycles.

18. The method of claim 17, further comprising:

spectrally shaping said burst of cycles to control bandwidth to meet at least one desired property.

19. The method of claim 18, wherein said at least one desired property comprises at least one of out of band emissions, in-band spectral flatness, time domain peak power, or burst off time attenuation.

20. The method of claim 11, wherein said plurality of reference radios are in communication with each other via wired or wireless means.