Economical magnetic locator apparatus and methods

• US 9,632,202 B2
• Filed: 06/08/2015
• Issued: 04/25/2017
• Est. Priority Date: 03/04/2010
• Status: Active Grant

• Current Assignee: Seescan, Inc.
• Original Assignee: Seescan, Inc.
• Inventors: Olsson, Mark S., Merewether, Ray
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US14/733,810
• Publication Number:
  US 20150338539A1
• Time in Patent Office: 687 Days
• Field of Search: 324329
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01B 7/26 for measuring depth
• CPC Class Codes: G01R 33/096 anisotropic magnetoresistance sensors
• CPC Class Codes: G01R 33/10 Plotting field distribution ; Measuring field distribution
• 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 3/165 operating with magnetic or electric fields produced or modified by the object or by the detecting device with electromagnetic waves G01V3/17
• CPC Class Codes: G01V 3/38 Processing data, e.g. for analysis, for interpretation, for correction

Abstract

Magnetic locators for detection of buried objects, such as ferromagnetic objects, are disclosed. Outputs provided from two or more magnetic sensors, such as three three-axis magnetic sensors, as well as optionally from other sensors, such as accelerometers and gyroscopic sensors, may be used to determine magnetic field distortion indicative of ferromagnetic objects and/or provide output information corresponding to the detected objects based on the sensor outputs.

Claims

1. An elongate vertically-oriented magnetic locator, comprising:

a lower housing element;

a first three-axis active electronic integrated circuit magnetic sensor, for sensing magnetic fields in three orthogonal axes, disposed on or within the lower housing element;

a second three-axis active electronic integrated circuit magnetic sensor, for sensing magnetic fields in three orthogonal axes, positioned above the first three-axis magnetic sensor when the locator is positioned in a vertical orientation in a standard operating position;

a circuit board module coupled to an output of the first three-axis magnetic sensor and the output of the second three-axis magnetic sensor for comparing the corresponding output signals from one of the three-axis magnetic sensors from output signals of the other of the three-axis magnetic sensors to determine at least in part a magnetic field distortion caused by a ferromagnetic object; and

an output element for providing an output associated with the ferromagnetic object based at least in part on the determined magnetic field distortion;

wherein the first magnetic sensor and the second magnetic sensor are calibrated so that B field measurements at the magnetic sensors are matched in one or more directions to normalize data generated therefrom.

2. The locator of claim 1, wherein the output element is a visual display disposed on or in the locator.

3. The locator of claim 1, wherein the output element is an audible output device disposed on or in the locator.

5. The locator of claim 1, wherein the circuit board module is disposed on or within the lower housing element.

6. The locator of claim 1, wherein the second three-axis magnetic sensor is disposed on or within the lower housing element.

7. The locator of claim 1, further comprising an accelerometer having an output signal coupled to the circuit board module, wherein the output associated with the ferromagnetic object is further based in part on an output signal from the accelerometer.

8. The locator of claim 1, further comprising a gyroscopic sensor having an output signal coupled to the circuit board module, wherein the output associated with the ferromagnetic object is further based in part on an output signal from the gyroscopic sensor.

9. The locator of claim 1, further comprising a GPS receiver having an output signal coupled to the circuit board module, wherein the output associated with the ferromagnetic object is further based in part on an output signal from the GPS receiver.

10. The locator of claim 1, further comprising one or more additional three-axis electronic integrated circuit magnetic sensors for sensing magnetic fields in three axes at a single point in space, the additional three-axis integrated circuit magnetic sensors having output signals coupled to the circuit board module, wherein the magnetic field distortion caused by the ferromagnetic object is further based on the output signals from the one or more additional three-axis integrated circuit magnetic sensors.

13. The magnetic locator of claim 1, wherein the first and the second magnetic field sensors are anisotropic magnetoresistive sensor (AMR) chips.

14. The magnetic locator of claim 1, wherein the comparing includes determining a magnetic B-field angular distortion associated with the ferromagnetic object as sensed from multiple axes by the first and second magnetic field sensors.

15. The magnetic locator of claim 1, wherein the first and the second magnetic field sensors are anisotropic magnetoresistive sensor (AMR) integrated circuits.

16. The magnetic locator of claim 1, wherein the comparing includes determining a magnetic B-field angular distortion associated with the ferromagnetic object as sensed from multiple axes by the first and second magnetic field sensors.

4. An elongate vertically-oriented magnetic locator, comprising:

a lower housing element

a first three-axis active electronic integrated circuit magnetic sensor, for sensing magnetic fields in three orthogonal axes, disposed on or within the lower housing element;

a second three-axis active electronic integrated circuit magnetic sensor, for sensing magnetic fields in three orthogonal axes, positioned above the first three-axis magnetic sensor when the locator is positioned in a vertical orientation in a standard operating position;

a circuit board module coupled to an output of the first three-axis magnetic sensor and the output of the second three-axis magnetic sensor for comparing the corresponding output signals from one of the three-axis magnetic sensors from output signals of the other of the three-axis magnetic sensors to determine at least in part a magnetic field distortion caused by a ferromagnetic object and

an output element for providing an output associated with the ferromagnetic object;

wherein the housing element includes a tapered point at the end of the locator positioned closest to the ground surface in a normal vertical operating orientation.

11. An elongate vertically-oriented magnetic locator for sensing a buried ferromagnetic object, comprising:

a first sensor circuit for generating a first output signal corresponding to magnetic fields sensed in three orthogonal axes at a single point in space from a three-axis electronic integrated circuit magnetic field sensor disposed in a locator housing element;

a second sensor circuit for generating a second output signal corresponding to magnetic fields sensed in three orthogonal axes at a single point in space from a second three-axis electronic integrated circuit magnetic field sensor positioned above the first three-axis magnetic field chip sensor when the locator is positioned in a vertical orientation;

a processing element for generating a signal corresponding to a magnetic field distortion caused by the ferromagnetic object by comparing corresponding first or second output signals from the other of the first or second output signals; and

an output device for providing an output corresponding to at least an estimated position or an estimated depth to the ferromagnetic object based in part on the magnetic field distortion;

wherein the first sensor circuit and the second sensor circuit are calibrated so that B field measurements at the magnetic sensors are matched in one or more directions to normalize data generated therefrom.

17. The magnetic locator of claim 11, wherein the three-axis magnetic field sensor comprises an AMR sensor.

18. The magnetic locator of claim 17, wherein the comparing includes determining a magnetic B-field angular distortion associated with the ferromagnetic object as sensed from multiple axes by the first and second magnetic field sensors.

12. A method of magnetically sensing an object with a an elongate vertically-oriented magnetic locator, comprising:

generating a first output signal corresponding to magnetic fields sensed in three orthogonal axes at a single point in space from an electronic integrated circuit magnetic field sensor disposed in a locator housing element;

generating a second output signal corresponding to magnetic fields sensed in three orthogonal axes at a single point in space from a second electronic integrated circuit magnetic field sensor positioned above the first three-axis magnetic field sensor when the locator is positioned in a standard vertical operational orientation;

generating a signal corresponding to a magnetic field distortion caused by the object by comparing corresponding first or second output signals from the other of the first or second output signals; and

providing an output corresponding at least an estimated position or an estimated depth to the object based in part on the magnetic field distortion

wherein the first magnetic field sensor and the second magnetic field sensor are calibrated so that B field measurements at the magnetic sensors are matched in one or more directions to normalize data generated therefrom.

19. The method of claim 12, wherein the three-axis magnetic field sensor comprises an AMR sensor.

20. The method of claim 19, wherein the comparing includes determining a magnetic B-field angular distortion associated with the ferromagnetic object as sensed from multiple axes by the first and second magnetic field sensors.