Smart Electromagnetic Sensor Array

• US 20130127448A1
• Filed: 11/16/2012
• Published: 05/23/2013
• 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
• Granted Patent: US 9,354,033 B2
• Time in Patent Office: Days
• US Class Current: 324/207.15
• 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 configured to sense a strength of a magnetic field induced by a signal in the wire at a plurality of locations;

a processor configured to determine the location and 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.

2. The system of claim 1, wherein 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 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 display configured to display the determined location and orientation of the wire relative to the plurality of sensors.

7. 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;

a plurality of filters each configured to receive 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 each of the sensors.

8. The system of claim 7, 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.

9. 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.

10. 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 located at a plurality of locations;

determining the location and orientation of the wire relative to the plurality of sensors based upon the sensed strength of the magnetic field at the plurality of locations;

providing the location and orientation of the wire to a user.

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

12. The method of claim 10, wherein providing the location and orientation comprises displaying the determined location and orientation of the wire on a display relative to a location of the plurality of sensors.

13. The method of claim 10, further comprising:

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

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 corresponds to the sensed magnetic field at each of the plurality of sensors.

14. The method of claim 13, further comprising amplifying the filtered signals and adjusting an amplifying gain using automatic gain control circuitry.

15. The method of claim 13, further comprising amplifying the filtered signals, wherein an amplifying gain is adjusted by the user.

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

a transmitter configured to generate a signal for transmitting in a wire to be detected;

a plurality of receivers configured to sense a strength of a magnetic field induced by the signal in the wire at a plurality of locations;

a processor configured to determine the location and orientation of the wire relative to the plurality of receivers based upon the sensed strength of the magnetic field at the plurality of locations;

a display configured to display the determined location and orientation of the wire relative to the plurality of receivers.

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

18. The test instrument of claim 17, wherein each induction coil sensor converts the sensed field to an electrical signal, and wherein the signal is a modulated signal having a frequency at a modulation frequency, and further 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.

19. The test instrument of claim 18, wherein each of the plurality of receivers further includes an amplifier to amplify the filtered electrical signal, and further wherein a gain of the amplifier is controlled using automatic gain control circuitry.

20. The test instrument of claim 18, wherein each of the plurality of receivers further includes an amplifier to amplify the filtered electrical signal, and further wherein a gain of the amplifier is controlled by a user.

21. The test instrument of claim 16, 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.