Smart electromagnetic sensor array

• US 9,354,033 B2
• Filed: 11/16/2012
• Issued: 05/31/2016
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Fluke Corporation (Fortive Corp.)
• Original Assignee: Fluke Corporation (Fortive Corp.)
• Inventors: Hyacinthe, John Wesley, Bras, Jaroslaw
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): Hawkins, Dominic
• Application Number:
  US13/679,819
• Publication Number:
  US 20130127448A1
• Time in Patent Office: 1,292 Days
• Field of Search: 324/207.13, 324/207.15, 324/207.16, 324/207.17
• US Class Current: 1/1
• CPC Class Codes: G01B 7/00 Measuring arrangements characterised by the use of electric or magnetic techniques
• CPC Class Codes: G01R 33/0094 Sensor arrays
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat

Abstract

An array of induction coil sensors is used to monitor, from multiple locations, the strength of a magnetic field generated by a wire to be traced. The magnetic field strength data is used to determine the location and orientation of the wire. In one embodiment, the sensor array is incorporated into a test instrument. The screen of the test instrument provides a graphical user interface that shows the orientation of the wire and indicates the location of the wire relative to the instrument.

Claims

1. A system for determining a location and an orientation of a wire, the system comprising:

a plurality of sensors located at a respective plurality of locations that are fixed within the system, each sensor in the plurality of sensors being located spatially separate from the other sensors, wherein the sensors are configured to sense a strength of a magnetic field induced by a signal in the wire at the plurality of locations;

a processor configured to determine the location and the orientation of the wire relative to the plurality of sensors based upon the sensed strength of the magnetic field at the plurality of locations and provide the determined location and orientation of the wire to a user, wherein the determined location and orientation are indicative of both a position of the wire and an angular orientation of the wire with respect to the fixed locations of the plurality of sensors; and

a display configured to graphically display the determined location and orientation of the wire relative to the fixed locations of the plurality of sensors.

2. The system of claim 1, wherein the sensors in the plurality of sensors are induction coil sensors.

3. The system of claim 1, wherein the plurality of sensors comprises four induction coil sensors, wherein one of the four sensors is positioned at or near a midpoint of each of the four sides of a square.

4. The system of claim 1, wherein the sensors in the plurality of sensors are positioned substantially equidistant around a circle.

5. The system of claim 1, wherein the plurality of sensors comprises three sensors positioned substantially at the vertices of a triangle.

6. The system of claim 1, further comprising:

a transmitter configured to transmit the signal down the wire, wherein the signal is modulated at a signal frequency; and

a plurality of filters each configured to receive and filter an electrical signal from one of the plurality of sensors and transmit frequencies near the signal frequency of the modulated signal, wherein the electrical signal corresponds to a total sensed magnetic field by a respective one of the plurality of sensors.

7. The system of claim 6, further comprising a plurality of amplifiers configured to amplify the filtered signals, wherein a gain of each of the plurality of amplifiers is adjusted with automatic gain control circuitry so that the filtered signals are amplified near the middle of an operating range of the processor.

8. The system of claim 1, further comprising a memory configured to store readings at each of the plurality of sensors for a plurality of locations and orientations of a test wire relative to the plurality of sensors, wherein the processor determines the location and orientation of the wire further based on the stored readings.

20. The system of claim 1, wherein the processor is further configured to directionally guide a user of the system to reposition the plurality of sensors with respect to the wire to center the plurality of sensors over the location of the wire.

22. The method of claim 1, further comprising directionally guiding the user to reposition the plurality of sensors with respect to the wire to center the plurality of sensors over the location of the wire.

9. A method of determining a location and an orientation of a wire, the method comprising:

sensing a strength of a magnetic field induced by a signal in the wire using a plurality of sensors in a system, wherein the sensors are located at a respective plurality of locations that are fixed within the system;

determining the location and the orientation of the wire relative to the plurality of sensors based upon the sensed strength of the magnetic field at the plurality of locations, wherein determining the location and orientation of the wire includes comparing the sensed strength of the magnetic field at the plurality of locations with readings previously stored in a memory, the stored readings providing indications of a plurality of locations and orientations of a test wire relative to the fixed locations of the plurality of sensors, and determining the location and orientation of the wire based on the comparison with the stored readings, and wherein the determined location and orientation are indicative of both a position of the wire and an angular orientation of the wire with respect to the fixed locations of the plurality of sensors; and

providing to a user the determined location and orientation of the wire relative to the fixed locations of the plurality of sensors.

10. The method of claim 9, wherein the sensors in the plurality of sensors are induction coil sensors.

11. The method of claim 9, wherein providing the determined location and orientation comprises displaying the determined location and orientation of the wire on a display relative to the fixed locations of the plurality of sensors.

12. The method of claim 9, further comprising:

transmitting the signal down the wire, wherein the signal is modulated at a signal frequency; and

filtering an electrical signal from each of the plurality of sensors to pass frequencies near the signal frequency of the modulated signal, wherein the electrical signal from a respective sensor of the plurality of sensors corresponds to the sensed magnetic field at the respective sensor.

13. The method of claim 12, further comprising amplifying the filtered signals and adjusting an amplifying gain using automatic gain control circuitry so that the filtered signals are amplified near the middle of an operating range of one or more components used to determine the location and the orientation of the wire.

14. The method of claim 12, further comprising amplifying the filtered signals, wherein an amplifying gain is adjusted by the user.

21. The method of claim 9, further comprising requesting that the plurality of sensors be moved with respect to the wire, and thereafter redetermining the location and orientation of the wire relative to the fixed locations of the plurality of sensors based upon the sensed strength of the magnetic field at the new plurality of locations of the sensors, wherein redetermining the location and orientation of the wire includes comparing the sensed strength of the magnetic field at the new plurality of locations with the readings previously stored in the memory and determining the location and orientation of the wire based on the comparison with the stored readings and the previously-determined location and orientation of the wire relative to the new plurality of locations of the sensors.

15. A test instrument for determining a location and an orientation of a wire, comprising:

a plurality of receivers arranged in an array, wherein the receivers are configured to sense a strength of a magnetic field induced by a signal in the wire at a plurality of locations that are fixed within the array, each receiver in the array being located spatially separate from the other receivers;

a processor configured to determine the location and the orientation of the wire relative to the plurality of receivers based upon the sensed strength of the magnetic field at the plurality of locations, wherein the determined location and orientation are indicative of a position of the wire with respect to the plurality of receivers and an angular orientation of the wire with respect to the fixed locations of the plurality of receivers; and

a display configured to display the determined location and orientation of the wire relative to the fixed locations of the plurality of receivers,

wherein each of the plurality of receivers further includes an amplifier to amplify the filtered electrical signal, and wherein a gain of the amplifier is controlled using automatic gain control circuitry so that the filtered sink are amplified near the middle of an operating range of the processor.

16. The test instrument of claim 15, wherein each of the plurality of receivers includes an induction coil sensor.

17. The test instrument of claim 16, wherein each induction coil sensor converts the sensed magnetic field to an electrical signal, wherein the electrical signal is modulated at a modulation frequency, and wherein each of the plurality of receivers further includes a bandpass filter configured to filter the electrical signal to pass frequencies near the modulation frequency.

18. The test instrument of claim 17, wherein the gain of the amplifier is alternatively controlled by a user.

19. The test instrument of claim 15, further comprising a memory configured to store readings of the strength of the magnetic field at each of the receivers for a plurality of locations and orientations of a test wire relative to the plurality of receivers, wherein the processor determines the location and orientation of the wire to be detected further based on the stored readings.