Sondes and methods for use with buried line locator systems

• US 9,411,066 B1
• Filed: 01/23/2012
• Issued: 08/09/2016
• Est. Priority Date: 10/04/2003
• Status: Active Grant

• Current Assignee: Seescan, Inc.
• Original Assignee: Seescan, Inc.
• Inventors: Coduti, Anthony L., Olsson, Mark S., Martin, Michael J.
• Primary Examiner(s): Aurora, Reena
• Application Number:
  US13/356,408
• Time in Patent Office: 1,660 Days
• Field of Search: 324/326, 324/67, 343/728, 343/788, 343/867
• US Class Current: 1/1
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: G01V 3/104 using several coupled or uncoupled coils G01V3/101 takes precedence
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat
• CPC Class Codes: G01V 3/165 operating with magnetic or electric fields produced or modified by the object or by the detecting device with electromagnetic waves G01V3/17

Abstract

Sondes and sonde arrays for use with portable buried object locating systems are disclosed.

Claims

1. An orthogonal sonde array, comprising:

three or more antennas in a substantially orthogonal orientation, wherein each antenna includes;

a ferromagnetic core;

an insulating layer at least partially surrounding the core; and

a pair of conductive coils disposed around the insulating layer, wherein a first of each pair of conductive coils is positioned co-axially opposite a second of each pair of conductive coils on a cylindrical coil form.

2. The sonde array of claim 1, wherein each of the antennas has a substantially identical configuration, and wherein the antennas are arranged in three sets of orthogonally oriented pairs extending along X, Y, and Z axes.

3. The array of claim 1, wherein the antennas are disposed on a cylindrical bobbin.

4. The array of claim 3, wherein the ferromagnetic cores extend into the cylindrical bobbin.

5. The array of claim 4, further comprising a central block of magnetic material coupling each of the pairs of ferromagnetic cores.

6. The array of claim 1, wherein conductors of each of the pairs of conducting coils are wired electrically in-phase.

7. The array of claim 1, further comprising a level indicating device.

8. The array of claim 1, further comprising a null coil coupled to a capacitor bank.

9. A method of generating a test signal for locating a buried object, the method including:

providing a buried object location signal to be transmitted from a transmitter to a sonde array, wherein the sonde array includes three or more orthogonal antennas each in a substantially orthogonal orientation, wherein each antenna includes;

a ferromagnetic core;

an insulating layer at least partially surrounding the core; and

a pair of conductive coils disposed around the insulating layer, wherein a first of each pair of conductive coils is positioned co-axially opposite a second of each pair of conductive coils on a cylindrical coil form; and

sending the buried object location signal, as a magnetic field signal, from the antennas of the sonde array for reception by a buried utility locator.

10. The method of claim 9, wherein the buried object location signal is provided from a power amplifier operating at a single frequency as an output signal, and wherein the output signal is selectively switched from coil-to-coil in the pairs of conductive coils.

11. The method of claim 10, wherein the selective switching is done at substantially the zero current crossing points of the output signal.

12. The method of claim 9, wherein the transmitter includes a power amplifier operating at a drive frequency that is varied from coil-to-coil.

13. The method of claim 12, wherein the drive frequency is varied from coil-to-coil by an integer number of cycles.

14. A system for generating signals for detecting buried objects, comprising:

a transmitter; and

a sonde array coupled to the transmitter, the sonde array including;

three or more antennas in a substantially orthogonal orientation, wherein each antenna includes;

a ferromagnetic core;

an insulating layer at least partially surrounding the core; and

a pair of conductive coils disposed around the insulating layer, wherein a first of each pair of conductive coils is positioned co-axially opposite a second of each pair of conductive coils on a cylindrical coil form.

15. The system of claim 14, wherein the transmitter includes a power amplifier operating at a single frequency that selectively switches an output signal from coil-to-coil in the pairs of conductive coils.

16. The system of claim 15, wherein the selective switching is done at substantially the zero current crossing points of the output signal.

17. The system of claim 15, wherein the transmitter outputs an amplified square wave operating the frequency range of approximately 10 Hertz to 10 kHz, further comprising a cycle counter to determine coil-to-coil switching timing.

18. The system of claim 14, wherein the transmitter includes a power amplifier operating at a drive frequency that is varied from coil-to-coil.

19. The system of claim 18, wherein the drive frequency is varied from coil-to-coil by an integer number of cycles.

20. The system of claim 14, further comprising a level indicating device.

21. The system of claim 14, further comprising a capacitor bank and a null coil, wherein the null coil and the conductive coils are coupled to the capacitor bank.