System and method for position determination by impulse radio

• US 6,774,846 B2
• Filed: 05/20/2003
• Issued: 08/10/2004
• Est. Priority Date: 03/23/1998
• Status: Expired due to Term

• Current Assignee: Humatics Corporation
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Richards, James L., Fullerton, Larry W., Cowie, Ivan A.
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US10/441,078
• Publication Number:
  US 20030197643A1
• Time in Patent Office: 448 Days
• Field of Search: 342/387, 342/450, 342/457, 342/458
• US Class Current: 342/387
• 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: H04B 1/7183 Synchronisation
• CPC Class Codes: H04B 2001/6908 using time hopping

Abstract

A system and a method for position determination by impulse radio using a first transceiver having a first clock providing a first reference signal and a second transceiver placed spaced from the first transceiver. The system determines the position of the second transceiver. The second transceiver has a second clock that provides a second reference signal. A first sequence of pulses are transmitted from the first transceiver. The first sequence of pulses are then received at the second transceiver and the second transceiver is then synchronized with the first sequence of pulses. A second sequence of pulses are transmitted from the second transceiver. The first transceiver receives the second sequence of pulses and the first transceiver is synchronized with the second sequence of pulses. A delayed first reference signal is generated in response to the synchronization with the second sequence of pulses. A time difference between the delayed first reference signal and the first reference signal is then measured. The time difference indicates a total time of flight of the first and second sequence of pulses. The distance between the first and the second transceiver is determined from the time difference. The direction of the second transceiver from the first transceiver is determined using a directional antenna. Finally, the position of the second transceiver is determined using the distance and the direction.

Claims

1. A method for determining the position of an object, comprising:

positioning a first impulse radio a first distance from a second impulse radio;

associating a third impulse radio with said object, said object being spaced apart from said first impulse radio and said second impulse radio, said third impulse radio being not synchronized with said first impulse radio and said second impulse radio;

determining a first time of flight between said first impulse radio and said third impulse radio;

determining a second time of flight between said second impulse radio and said third impulse radio;

determining a second distance based on said first time of flight;

determining a third distance based on said second time of flight;

determining said position of said object based on triangularization of said first distance, said second distance, and said third distance.

2. The method of claim 1, further comprising:

resolving a position ambiguity based on a received signal strength at a directional antenna that covers a position ambiguity area.

3. The method of claim 1, further comprising:

resolving a position ambiguity based on a relative received signal strength at two or more directional antennas positioned to cover corresponding position ambiguity areas.

4. The method of claim 1, further comprising:

resolving a position ambiguity using a fourth impulse radio.

5. The method of claim 4, wherein said resolving a position ambiguity using a fourth impulse radio comprises:

positioning said fourth impulse radio a fourth distance from said first impulse radio;

determining a third time of flight between said fourth impulse radio and said third impulse radio;

determining a fifth distance from said third time of flight; and

determining said position of said object based on triangularization of said first distance, said second distance, said third distance, said fourth distance, and said fifth distance.

6. The method of claim 4, further comprising:

resolving an elevation ambiguity using a fifth impulse radio.

7. The method of claim 1, wherein information is conveyed comprising at least one of digital data, digitized voice, and analog modulation.

8. The method of claim 7, wherein said information is conveyed by modulating a transmitted pulse waveform using one of amplitude modulation, phase modulation, frequency modulation, and time shift modulation.

9. The method of claim 8, wherein said transmitted pulse waveform approaches one cycle at a center frequency.

10. The method of claim 8, wherein said transmitted pulse waveform consists of a burst of cycles.

11. A system for determining the position of an object, comprising:

a first impulse radio;

a second impulse radio positioned apart from said first impulse radio by a first distance;

a third impulse radio, said third impulse radio being associated with said object, said object being spaced apart from said first impulse radio and said second impulse radio, said third impulse radio being not synchronized with said first impulse radio and said second impulse radio; and

one or more processors adapted to determine a first time of flight between said first impulse radio and said third impulse radio, a second time of flight between said second impulse radio and said third impulse radio, a second distance based on said first time of flight, a third distance based on said second time of flight, and said position of said object based on triangularization of said first distance, said second distance, and said third distance.

12. The system of claim 11, further comprising:

a directional antenna that covers a position ambiguity area for resolving a position ambiguity based on a received signal strength at the directional antenna.

13. The system of claim 11, further comprising:

two or more directional antennas positioned to cover corresponding position ambiguity areas for resolving a position ambiguity based on a relative received signal strength at the two or more directional antennas.

14. The system of claim 11, further comprising:

a fourth impulse radio used to resolve a position ambiguity.

15. The system of claim 14, wherein said fourth impulse radio is positioned a fourth distance from said first impulse radio and said one or more processors are further adapted to determine a third time of flight between said fourth impulse radio and said third impulse radio, a fifth distance from said third time of flight, and said position of said object based on triangularization of said first distance, said second distance, said third distance, said fourth distance, and said fifth distance.

16. The system of claim 14, further comprising:

a fifth impulse radio used to resolve an elevation ambiguity.

17. The system of claim 11, wherein information is conveyed comprising at least one of digital data, digitized voice, and analog modulation.

18. The system of claim 17, wherein said information is conveyed by modulating a transmitted pulse waveform using one of amplitude modulation, phase modulation, frequency modulation, and time shift modulation.

19. The system of claim 18, wherein said transmitted pulse waveform approaches one cycle at a center frequency.

20. The system of claim 18, wherein said transmitted pulse waveform consists of a burst of cycles.