Sensor for sensing an electric field

• US 20060139031A1
• Filed: 09/13/2005
• Published: 06/29/2006
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Osmose Utilities Services Incorporated (Osmose Holdings Incorporated)
• Original Assignee: Power Survey Corporation
• Inventors: Kalokitis, David, Zalud, Peter, Vannozzi, Frederick John, Polyzois, Christos Alkiviadis, Lang, Frank Bowen, Berends, David Christopher
• Granted Patent: US 7,248,054 B2
• Time in Patent Office: Days
• US Class Current: 324/457
• CPC Class Codes: G01R 29/0871 Complete apparatus or systems; circuits, e.g. receivers or amplifiers G01R29/0878, G01R29/0892 take precedence; dosimeters, warning devices G01R29/0857
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24
• CPC Class Codes: G01R 31/085 in power transmission or distribution lines, e.g. overhead

Abstract

A sensor for sensing an electric field includes a movable sensor probe including one or more pair, typically three pair, of electrically conductive electrodes, and may include one or more pair of selectively switchable auxiliary electrodes. The probe is movable and may be mounted on a vehicle or trailer. A processor may process electric field signals from the probe for providing a human perceivable indication of the electric field. The processor may perform a Fast Fourier Transform of the electric field signals to produce an indication of the magnitude of the electric field, and may perform unweighted and/or weighted averaging in relation to processing electric field data, setting a comparison threshold, providing a human perceivable indication, or a combination of the foregoing. A speed at which the sensor probe is moving may be utilized in processing the data.

Claims

1. A sensor for sensing an electric field comprising:

a sensor probe for producing electrical signals representative of an electric field and being movable to be in an electric field, said sensor probe including;

a first pair of electrically conductive electrodes spaced apart along a first axis,

a second pair of electrically conductive electrodes spaced apart along a second axis that is orthogonal to the first axis, and

a third pair of electrically conductive electrodes spaced apart along a third axis that is orthogonal to the first and second axes;

an analog to digital converter coupled to said first, second and third pairs of spaced apart electrically conductive electrodes for digitizing the electrical signals representative of the electric field;

a source of location information, or speed information, or both, representative of the location, or speed, or both, of said sensor probe;

a processor coupled to said analog to digital converter and to said source of location information, or speed information, or both, for processing the digitized electrical signals from said analog to digital converter by a Fast Fourier Transform at a rate that is a multiple of an expected frequency of the electric field, by averaging the Fast Fourier Transformed digitized electrical signals at a rate that is representative of the speed at which said sensor probe is moving, and by comparing the averaged Fast Fourier Transformed digitized electrical signals to a threshold for providing a human perceivable indication of the electric field.

2. The sensor of claim 1 further comprising:

a fourth pair of electrically conductive electrodes spaced apart for defining a space therebetween, wherein said first, second and third pairs of electrically conductive electrodes of said sensor probe are disposed in the space between said fourth pair of electrically conductive electrodes; and

a switch for selectively electrically connecting said fourth pair of electrically conductive electrodes together, or for selectively electrically connecting said fourth pair of electrically conductive electrodes to a common reference, or for selectively electrically connecting said fourth pair of electrically conductive electrodes together and to a common reference.

3. The sensor of claim 2 wherein said fourth pair of electrically conductive electrodes are spaced apart along one of the first, second and third axes.

4. The sensor of claim 1 further comprising a storage device for storing the digitized electrical signals from said analog to digital converter, or the Fast Fourier Transformed digitized electrical signals, or the averaged Fast Fourier Transformed digitized electrical signals, or the human perceivable indication of the electric field, or the location information, or the speed information, or any combination of the foregoing.

5. The sensor of claim 1 further comprising an interface for displaying in a form visually perceivable by a human the digitized electrical signals from said analog to digital converter, or the Fast Fourier Transformed digitized electrical signals, or the averaged Fast Fourier Transformed digitized electrical signals, or the human perceivable indication of the electric field, or any combination of the foregoing.

6. The sensor of claim 5 wherein said interface further provides a graphical user interface for controlling said processor.

7. The sensor of claim 6 wherein said graphical user interface provides commands for:

selecting a mode for said first, second and third pairs of electrically conductive electrodes wherein the modes include providing electrical signals for each electrode individually and providing electrical signals for each pair of electrodes differentially;

or

selecting a mode for a pair of electrically conductive auxiliary electrodes wherein the modes include not connecting the pair of auxiliary electrodes, or connecting the pair of auxiliary electrodes together, or connecting the pair of auxiliary electrodes to a common reference, or any combination of the foregoing;

or

adjusting the threshold with which the averaged Fast Fourier Transformed digitized electrical signals is compared;

or

changing the manner in which the threshold with which the averaged Fast Fourier Transformed digitized electrical signals is determined;

or

changing the averaging between an unweighted average and a weighted average and, if a weighted average, changing weighting factors of the weighted average;

or

changing the relationship between pitch of an audible tone comprising the human perceivable indication and;

the digitized electrical signals from said analog to digital converter, or the Fast Fourier Transformed digitized electrical signals, or the averaged Fast Fourier Transformed digitized electrical signals, or the human perceivable indication of the electric field, or any combination of the foregoing;

or

displaying the digitized electrical signals from said analog to digital converter, or the Fast Fourier Transformed digitized electrical signals, or the averaged Fast Fourier Transformed digitized electrical signals, or the human perceivable indication of the electric field, or any combination of the foregoing;

or

displaying a help screen including a list of commands;

or

any combination of the foregoing.

8. A sensor for sensing an electric field comprising:

a sensor probe for producing electrical signals representative of an electric field and being movable to be in an electric field, said sensor probe including;

a first pair of electrically conductive rectangular electrodes spaced apart along a first axis;

a second pair of electrically conductive rectangular electrodes spaced apart along a second axis that is orthogonal to the first axis; and

a third pair of electrically conductive rectangular electrodes spaced apart along a third axis that is orthogonal to the first and second axes;

a rigid dielectric support structure having six faces for locating said first, second and third pairs of electrically conductive rectangular electrodes for defining a substantially cubical arrangement of electrodes; and

at least three high-input impedance amplifiers having respective inputs coupled to said first, second and third pairs of electrically conductive rectangular electrodes for receiving signals therefrom responsive to the electric field.

9. The sensor of claim 8 further comprising a processor for processing electrical signals from said at least three high input impedance amplifiers by a Fast Fourier Transform at a rate that is a multiple of an expected frequency of the electric field, by averaging the Fast Fourier Transformed digitized electrical signals at a rate that is representative of a speed at which said sensor probe is moving, and by comparing the averaged Fast Fourier Transformed digitized electrical signals to a threshold for providing a human perceivable indication of the electric field.

10. The sensor of claim 8 further comprising:

a fourth pair of electrically conductive electrodes spaced apart for defining a space therebetween, wherein said first, second and third pairs of electrically conductive rectangular electrodes are disposed in the space between said fourth pair of electrically conductive electrodes; and

a switch for selectively electrically connecting said fourth pair of electrically conductive electrodes together, or for selectively electrically connecting said fourth pair of electrically conductive electrodes to a common reference, or for selectively electrically connecting said fourth pair of electrically conductive electrodes together and to a common reference.

11. The sensor of claim 10 wherein said fourth pair of electrically conductive electrodes are spaced apart along one of the first, second and third axes.

12. The sensor of claim 8 wherein said rigid dielectric support structure comprises wood.

13. The sensor of claim 8 wherein said rigid dielectric support structure is mounted on a motor vehicle, or is mounted on a trailer towable by a motor vehicle, or is cantilevered from a motor vehicle, or is cantilevered from a trailer towable by a motor vehicle.

14. The sensor of claim 8 wherein said rigid dielectric support structure comprises:

four planar trapezoidal sides each having a base and an edge parallel to the base, and each defining one of four adjacent side surfaces of a cube;

a planar square end attached to the four planar trapezoidal sides at the edge opposite the respective bases thereof and defining a fifth surface of the cube; and

a planar square base attached to the four planar trapezoidal sides at the respective bases thereof and defining a sixth surface of the cube.

15. The sensor of claim 14 wherein said first pair of electrically conductive rectangular electrodes are supported respectively by two opposing ones of said four planar trapezoidal sides, wherein said second pair of electrically conductive rectangular electrodes are supported respectively by another two opposing ones of said four planar trapezoidal sides, and wherein said third pair of electrically conductive rectangular electrodes are supported respectively by said planar square base and said planar square end.

16. A sensor for sensing an electric field comprising:

a sensor probe having at least one pair of spaced apart electrically conductive electrodes, said sensor probe being movable to be in an electric field;

a source of location information representative of the location of said sensor probe;

a processor for receiving signals from the at least one pair of electrodes of said sensor probe and from said source of location information for producing a signal responsive to the received signals and to the location information, wherein the signal produced by said processor is representative of the electric field;

said sensor further comprising;

an interface responsive to the signal produced by said processor for providing in a form perceivable by a human an indication of the electric field;

or

a storage device for storing the signal produced by said processor;

or

an interface responsive to the signal produced by said processor for providing in a form perceivable by a human an indication of the electric field and a storage device for storing the signal produced by said processor.

17. The sensor of claim 16 further comprising a high input impedance amplifier having an input connected to the pair of spaced apart conductive electrodes and having an output coupled to said processor.

18. The sensor of claim 16 further comprising:

a second pair of electrically conductive electrodes spaced apart for defining a space therebetween, wherein said sensor probe is disposed in the space between said second pair of electrically conductive electrodes; and

a switch for selectively electrically connecting said second pair of electrically conductive electrodes together, or for selectively electrically connecting said second pair of electrically conductive electrodes to a common reference, or for selectively electrically connecting said second pair of electrically conductive electrodes together and to a common reference.

19. The sensor of claim 16 wherein said processor includes a digital signal processor and an analog-to-digital converter coupled for providing to said digital signal processor digitized signals representative of the signals received from said sensor probe.

20. The sensor of claim 16 wherein said source of location information comprises a speed measuring device, or a distance measuring device, or a wheel speed sensor, or a wheel revolution sensor, or a GPS receiver, or an imager, or a video imager, or a TV camera, or any combination of the foregoing.

21. The sensor of claim 16 wherein said storage device stores the location information corresponding to the stored the signal produced by said processor in known relationship to the stored signal produced by said processor.

22. The sensor of claim 16 wherein the indication produced by said processor is responsive to an average of the magnitude of the signal produced by said processor, or to a weighted average of the magnitude of the signal produced by said processor, or to a comparison of a present value representative of the magnitude of the electric field and an average of previous values representative of the magnitude of the electric field, or to a comparison of a present value representative of the magnitude of the electric field and a weighted average of previous values representative of the magnitude of the electric field, or to any combination of the foregoing.

23. The sensor of claim 22 wherein the comparison is made with respect to a threshold, and wherein:

the weight applied to the present value for determining the weighted average when the present value exceeds the threshold is substantially smaller than the weighting factor applied to the present value when the present value does not exceed the threshold;

the weight applied to the present value for determining the weighted average when the present value exceeds the value of the weighted average is smaller than the weighting factor applied to the present value when the present value does not exceed the value of the weighted average;

the threshold is a predetermined value;

the threshold is a selectable multiple of the average or of the weighted average;

or

any combination of the foregoing.

24. The sensor of claim 16 wherein the indication produced by said processor includes an audible signal, or a pitch modulated audible signal, or an amplitude modulated audible signal, or a pulsing audible signal, or a visual indication, or a light, or an indication on a graphical user interface of a computer, or any combination of the foregoing.

25. The sensor of claim 16 mounted on a motor vehicle, mounted on a trailer towable by a motor vehicle, cantilevered from a motor vehicle, or cantilevered from a trailer towable by a motor vehicle.

26. The sensor of claim 16 wherein the indication in a form perceivable by a human includes an audible tone having a pitch that is:

logarithmically related to electric field strength, or

changed by about a one octave change in pitch for each about 10 dB change in electric field strength, or

incremented by an increment that is less than or equal to about an eighth of a step in an equal tempered chromatic scale, or

in a range from about 70 Hz to about 3 KHz, or

any combination of the foregoing.

27. A sensor for sensing an electric field comprising:

a sensor probe for producing electrical signals representative of an electric field and being movable to be in an electric field, said sensor probe including;

a first pair of electrically conductive electrodes spaced apart along a first axis;

a second pair of electrically conductive electrodes spaced apart along a second axis that is orthogonal to the first axis; and

a third pair of electrically conductive electrodes spaced apart for defining a space therebetween, wherein said first and second pairs of electrically conductive electrodes are disposed in the space between said third pair of electrically conductive electrodes;

at least two high-input impedance amplifiers having respective inputs coupled respectively to said first and second pairs of electrically conductive electrodes for receiving signals therefrom responsive to the electric field; and

a switch for selectively electrically connecting said third pair of electrically conductive electrodes together, or for selectively electrically connecting said third pair of electrically conductive electrodes to a common reference, or for selectively electrically connecting said third pair of electrically conductive electrodes together and to a common reference.

28. The sensor of claim 27 wherein said third pair of electrically conductive electrodes are spaced apart along one of the first and second axes;

or wherein said third pair of electrically conductive electrodes have a larger area than that of said first or second pair of electrically conductive electrodes, or wherein said third pair of electrically conductive electrodes are spaced apart along one of the first and second axes and have a larger area than that of said first or second pair of electrically conductive electrodes.

29. The sensor of claim 27 wherein said at least two high-input impedance amplifiers comprise:

four high-input impedance amplifiers each having a respective input coupled to a respective one of the electrodes of said first and second pairs of electrically conductive electrodes;

or

two high-input impedance differential amplifiers each having respective differential inputs coupled to a respective one of said first and second pairs of electrically conductive electrodes.

30. The sensor of claim 27 further comprising:

a fourth pair of electrically conductive electrodes spaced apart along a third axis that is orthogonal to the first and second axes, wherein said fourth pair of electrically conductive electrodes are disposed in the space between said third pair of electrically conductive electrodes; and

a third high-input impedance amplifier having an input coupled to said fourth pair of electrically conductive electrodes for receiving signals therefrom responsive to the electric field.