System and method for position determination by impulse radio

• US 6,297,773 B1
• Filed: 04/05/2000
• Issued: 10/02/2001
• 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): Pham, Dao L.
• Application Number:
  US09/517,161
• Time in Patent Office: 545 Days
• Field of Search: 342/134, 342/202, 342/450, 342/463, 342/457, 342/132, 342/375
• US Class Current: 342/457
• 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. An impulse radio position determination system comprising:

a first transceiver comprising

a first time base adapted to generate a first timing signal;

a first code time modulator adapted to generate a first coded timing signal based on both said first timing signal and a first code signal;

a first output stage adapted to output first coded pulses based on said first coded timing signal;

a first cross correlator; and

a first filter;

a second transceiver spaced from said first transceiver, said second transceiver adapted to receive said first coded pulses, said second transceiver comprising

a second cross correlator adapted to generate an output signal based on said first coded pulses and a decode signal;

a second filter adapted to generate an error signal responsive to said output signal;

a second time base adapted to be synchronized based on said error signal, and thereafter to generate a second timing signal;

a second code time modulator adapted to generate a second coded timing signal based on said second timing signal and a second code signal;

a second output stage adapted to output second coded pulses based on said second coded timing signal; and

wherein

said first transceiver is adapted to receive said second coded pulses,

said first cross correlator is adapted to generating a further output signal based on said second coded pulses and a further decode signal,

said first filter is adapted to generate a further error signal responsive to said further output signal,

said first time base is also adapted to be synchronized based on said further error signal, and thereafter to generate a delayed first timing signal, and

wherein information relating to a position of said second transceiver is determined based on a time difference between said delayed first timing signal and said first timing signal, said time difference relating to a total time of flight of said first coded pulses and said second coded pulses.

2. The system of claim 1, wherein a distance between said first and second transceivers is determined from said time difference.

3. The system of claim 2, further comprising a direction finding antenna for determining an angular direction of said second transceiver from said first transceiver, wherein the position of said second transceiver is determined from said distance and said angular direction.

4. The system of claim 1, wherein a plurality of first transceivers are positioned spaced apart from each other and apart from said second transceiver.

5. The system of claim 4, wherein the distance between each of said first transceivers and said second transceiver is determined.

6. The system of claim 5, wherein the position of said second transceiver is determined using triangulation.

7. The system of claim 1, wherein said first time base is adapted to be synchronized by coherent detection using said first cross correlator, and said second time base is adapted to be synchronized by coherent detection using said second cross correlator.

8. The system of claim 1, wherein said second transceiver is installed in a mobile telephone.

9. An impulse radio position determination system comprising:

a first transceiver comprising

a first time base adapted to generate a timing signal;

a code time modulator adapted to generate a coded timing signal based on both said first timing signal and a code signal;

an output stage adapted to output coded pulses based on said coded timing signal;

a second transceiver spaced from said first transceiver, said second transceiver adapted to receive said coded pulses, said second transceiver comprising

a second time base initially synchronized with said first time base;

a cross correlator adapted to generate an output signal based on said coded pulses and a decode signal;

a filter adapted to generate an error signal responsive to said output signal;

wherein said second time base is adapted to be further synchronized based on said error signal, and thereafter to generate a delayed timing signal;

wherein information relating to a position of said second transceiver is determined based on a time difference between said delayed timing signal and said timing signal, said time difference relating to a time of flight of said first coded pulses from said first transceiver to said second transceiver.

10. The system of claim 9, wherein a distance between said first and second transceivers is determined from said time difference.

11. The system of claim 10, further comprising a direction finding antenna for determining an angular direction of said second transceiver from said first transceiver, wherein the position of said second transceiver is determined from said distance and said angular direction.

12. The system of claim 10, wherein a plurality of first transceivers are positioned spaced apart from each other and apart from said second transceiver.

13. The system of claim 12 , wherein the distance between each of said first transceivers and said second transceiver is determined.

14. The system of claim 13, wherein the position of said second transceiver is determined using triangulation.

15. The system of claim 9, wherein said second time base is adapted to be further synchronized by coherent detection using said cross correlator.

16. The system of claim 9, wherein said second transceiver is installed in a mobile telephone.

17. An impulse radio receiver adapted to receive coded pulses from an impulse radio transmitter spaced from the impulse radio receiver, the coded pulses being generated in response to a timing signal generated by a transmit time base of the impulse radio transmitter, the impulse radio receiver comprising:

a receive time base initially synchronized with the transmit time base of the impulse radio transmitter;

a cross correlator adapted to generate an output signal based on said coded pulses and a decode signal;

a filter adapted to generate an error signal responsive to said output signal;

wherein said receive time base is adapted to be further synchronized based on said error signal, and thereafter to generate a delayed timing signal;

wherein information relating to a position of the receiver is determined based on a time difference between said delayed timing signal and the timing signal, said time difference relating to a time of flight of the coded pulses from the transmitter to the receiver.

18. The receiver of claim 17, wherein a distance between said transmitter and receiver is determined from said time difference.

19. The receiver of claim 18, further comprising a direction finding antenna for determining an angular direction from which the coded pulses were received from the transmitter, wherein a position of the receiver is determined from said distance and said angular direction.

20. The receiver of claim 18, wherein a plurality of transmitters are positioned spaced apart from each other and apart from the receiver, the distance between each of the transmitters and the receiver is determined, and a position of the receiver is determined using triangulation.