Interactive method and apparatus for locating and identifying utilities

• US 6,437,572 B1
• Filed: 11/13/2000
• Issued: 08/20/2002
• Est. Priority Date: 06/16/2000
• Status: Expired due to Term

• Current Assignee: Norscan Instruments Ltd.
• Original Assignee: Norscan Inc.
• Inventors: Vokey, David E.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US09/709,417
• Time in Patent Office: 645 Days
• Field of Search: 324/326, 324/329, 324/67, 324/528-530, 379/25, 340/551, 340/572.1, 340/572.5, 455/40, 455/66
• US Class Current: 324/326
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00

Abstract

The invention provides an interactive means to locate and identify underground utilities. The apparatus is used with a marker associated with an elongate electrical conductor, which may be a cable shield or a trace wire. It includes a remote, portable probe that is used to transmit a RF signal to be received by a transponder associated with the marker. The transponder is powered by a DC potential on the conductor. In preferred embodiments it has the capability of communicating with a terminal unit over the conductor to transmit information and instructions between the probe and the terminal unit.

Claims

1. An apparatus for identifying a marker associated with an elongate electrical conductor said apparatus, comprising:

a probe including;

a probe receiver for receiving radio frequency response signals;

a transponder associated with the marker and including;

a response signal transmitter for selectively transmitting to the probe each of a plurality of radio frequency response signals representing characteristic information about the marker or the conductor; and

a processor responsive to receipt of a radio frequency probe signal by the probe signal receiver to cause the response signal transmitter to transmit a radio frequency response signal, the transponder including;

a transponder processor for converting at least selected radio frequency probe signals received from the probe to low baud rate signals corresponding to the selected probe signals; and

a low baud rate transmitter for transmitting the low baud rate signals over the conductor.

2. An apparatus according to claim 1 wherein the transponder further includes a low baud rate receiver for receiving low baud rate response signals from the conductor and the transponder processor includes means for converting the low baud rate response signals to radio frequency response signals and causing the response signal transmitter to transmit the radio frequency response signals.

3. An apparatus according to claim 2 wherein the terminal unit includes a terminal unit processor with a memory for recording a plurality of terminal unit response signals, the processor being responsive to receipt of a low baud rate signal to select one of the terminal unit response signals corresponding to the received low baud rate command signal.

4. An apparatus according to claim 3 wherein the transponder includes a programmable memory and at least one of the terminal unit response signals comprises means for programming said programmable memory.

5. An apparatus according to claim 1 including a terminal unit connected to the conductor and including a terminal receiver for receiving low baud rate signals from the conductor and a terminal transmitter for transmitting low baud rate response signals on the conductor.

6. An apparatus according to claim 5 wherein the terminal unit includes means for causing the actuation of a remote device.

7. An apparatus according to claim 6 wherein the remote device is a tone signal generator.

8. An apparatus according to claim 5 wherein the terminal unit includes a communications interface coupled to the processor and to a communications network external to the terminal unit for transmitting data therebetween.

9. An apparatus according to claim 5 wherein:

the terminal unit includes a power supply for applying electric power to the conductor; and

a power supply for receiving electric power from the conductor and for delivering the electrical power to the transponder.

10. An apparatus according to claim 9 wherein the electrical power is DC power.

11. An apparatus according to claim 10 wherein the DC power has a negative polarity with respect to ground.

12. An apparatus according to claim 1 wherein the conductor is associated with a communications cable.

13. An apparatus according to claim 12 wherein the conductor is a metallic shield of the cable.

14. An apparatus according to claim 12 wherein the conductor is a trace wire.

15. An apparatus according to claim 1 wherein the probe includes a manual input for selecting a probe signal to be transmitted.

16. An apparatus according to claim 1 wherein the probe includes a display for displaying a response corresponding to a response signal received.

17. An apparatus according to claim 1 wherein the transponder includes a memory for recording a plurality of response signals and the processor is responsive to receipt of a probe signal by the probe signal receiver to select one of the response signals corresponding to the command signal for transmission by the response signal transmitter.

18. An apparatus for identifying a marker associated with an elongate electrical conductor, comprising:

a probe including;

a probe transmitter for selectively transmitting a radio frequency probe signal;

a probe receiver for receiving radio frequency response signals;

a transponder associated with the marker and including;

a radio frequency command signal receiver for receiving probe signals from the probe;

a radio frequency transmitter for transmitting radio frequency response signals;

a low baud rate transponder transmitter for transmitting low baud rate signals on said conductor;

a low baud rate transponder receiver for receiving from said conductor the low baud rate response signals transmitted thereon by the low baud rate transponder transmitter;

a processor for converting radio frequency command signals received by the radio frequency command signal receiver to low baud rate signals and causing the low baud rate transponder transmitter to transmit the low baud rate command signals, for converting low baud rate signals received by the low baud rate transponder receiver to radio frequency response signals and for causing the radio frequency transmitter to transmit the radio frequency response signals.

19. An apparatus according to claim 18 including a terminal unit connected to the conductor and including:

a terminal receiver for receiving low baud rate signals from the conductor; and

a terminal transmitter for transmitting low baud rate response signals on the conductor.

20. An apparatus according to claim 19 wherein the terminal unit includes a terminal unit processor with a memory for recording a plurality of terminal unit response signals, the processor being responsive to receipt of a low baud, rate signal to select one of the terminal unit response signals corresponding to the received low baud rate command signal.

21. An apparatus according to claim 20 wherein the transponder includes a programmable memory and at least one of the terminal unit response signals comprises means for programming said programmable memory.

22. An apparatus according to claim 19 wherein the terminal unit includes means for causing the actuation of a remote device.

23. An apparatus according to claim 22 wherein the remote device is a tone signal generator.

24. An apparatus according to claim 19 wherein the terminal unit includes a communications interface coupled to the processor and to a communications network external to the terminal unit for transmitting data therebetween.