Method and apparatus for detecting buried objects

• US 9,052,394 B2
• Filed: 10/06/2009
• Issued: 06/09/2015
• Est. Priority Date: 10/06/2009
• Status: Expired due to Fees

• Current Assignee: Louisiana Tech Research Corporation
• Original Assignee: Louisiana Tech University
• Inventors: Allouche, Erez N., Jaganathan, Arun, Simicevic, Neven
• Primary Examiner(s): Aurora, Reena
• Application Number:
  US13/500,722
• Publication Number:
  US 20130071213A1
• Time in Patent Office: 2,072 Days
• Field of Search: 324/326, 324/329, 324/67, 324/332, 324/344, 324/337
• US Class Current: 1/1
• CPC Class Codes: E02F 1/00 General working methods with dredgers or soil-shifting machines methods for making embankments E02D17/18; methods for mining E21C
• CPC Class Codes: E02F 3/28 with digging tools mounted on a dipper- or bucket-arm , i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
• CPC Class Codes: E02F 9/245 for preventing damage to underground objects during excavation, e.g. indicating buried pipes or the like detection of pipes in the ground F16L1/11
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/10 using transmission of interrupted, pulse modulated waves determination of distance by phase measurement G01S13/32
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01S 7/41 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat

Abstract

An object detection system (24) is disclosed having a transducer (40, 40′) for detecting buried objects (26). The transducer is encapsulated within a robust, electromagnetically transparent construction (42).

Claims

1. A construction vehicle including:

a chassis;

a plurality of traction devices positioned to support the chassis;

a work tool supported by the chassis and configured to penetrate the ground, the work tool including a bucket and a plurality of teeth coupled to the bucket; and

a plurality of detectors mounted to the work tool and configured to detect an object positioned in the ground during a penetration of the ground with the work tool, each detector being mounted to a different tooth of the work tool, at least one detector including a dielectric medium and a transmitter positioned in the dielectric medium operative to transmit a ground-penetrating signal, the dielectric medium and the ground having substantially the same dielectric properties to substantially reduce signal loss during a communication of the ground-penetrating signal, the at least one detector being configured to detect metal and non-metal objects positioned in the ground, the at least one detector further including an electromagnetic insulating material substantially coating the dielectric medium to insulate the transmitter from adjacent conductive surfaces to reduce at least one of signal leakage and ringing.

2. The construction vehicle of claim 1, wherein each detector includes at least one transducer and a dielectric medium, and the at least one transducer is configured to communicate a ground-penetrating signal.

3. The construction vehicle of claim 2, wherein the dielectric medium is positioned between the at least one transducer and the ground during a communication of the ground-penetrating signal to substantially reduce signal loss during the communication of the ground-penetrating signal between the at least one transducer and the ground, and the plurality of detectors are configured to communicate the ground-penetrating signal in a plurality of directions.

4. The construction vehicle of claim 3, wherein the dielectric medium contacts the ground during the communication of the ground-penetrating signal.

5. The construction vehicle of claim 2, wherein the at least one transducer is configured to transmit the ground-penetrating signal to the object positioned in the ground and receive a reflection signal of the ground-penetrating signal from the object.

6. The construction vehicle of claim 5, further including a processor configured to calculate a distance between the at least one transducer and the object based on a time delay between the transmission of the ground-penetrating signal and the reception of the reflection signal.

7. The construction vehicle of claim 5, further including a processor configured to characterize the object based on the reflection signal.

8. The construction vehicle of claim 1, wherein each detector is mounted near a cutting surface of the work tool.

9. A detector assembly configured to detect an object positioned in the ground, the detector assembly including:

at least one transducer configured to communicate a ground-penetrating signal, the at least one transducer including a plurality of antennas including at least one transmitting antenna configured to transmit the ground-penetrating signal and an array of receiving antennas configured to detect a reflection signal of the ground-penetrating signal from the object; and

a dielectric medium substantially encapsulating the at least one transducer to substantially reduce signal loss during a communication of the ground-penetrating signal between the at least one transducer and the ground, the dielectric medium being configured to contact the ground during the communication of the ground-penetrating signal, the plurality of antennas each being substantially encapsulated in the dielectric medium and each being mounted along a cutting surface of the work tool, the dielectric medium defining a leading cutting edge of the work tool.

10. The detector assembly of claim 9, further including a work tool configured to penetrate the ground, the at least one transducer being mounted to the work tool.

11. The detector assembly of claim 10, wherein the work tool is an excavator bucket.

12. The detector assembly of claim 9, wherein the at least one transducer is configured to transmit the ground-penetrating signal to the object positioned in the ground and receive a reflection signal of the ground-penetrating signal from the object.

13. The detector assembly of claim 9, wherein the at least one transducer is part of a transducer array.

14. The detector assembly of claim 9, wherein the dielectric medium is one of a polymer and a ceramic.

15. The detector assembly of claim 9, further including an electromagnetic insulating material substantially coating the dielectric medium.

16. The detector assembly of claim 9, further including a coating material substantially coating the dielectric medium and having a hardness greater than the hardness of the dielectric medium.

17. A detector assembly configured to detect an object positioned in the ground, the detector assembly including:

a work tool configured to penetrate the ground, the work tool including a plurality of teeth;

at least one transducer coupled to a tooth of the work tool and configured to communicate a ground-penetrating signal, the at least one transducer including an antipodal Vivaldi antenna spanning a majority of a length of the tooth; and

a dielectric medium positioned between the at least one transducer and the ground during a communication of the ground-penetrating signal to substantially reduce signal loss during the communication of the ground-penetrating signal between the at least one transducer and the ground.

18. The detector of claim 17, wherein the dielectric medium contacts the ground during the communication of the ground-penetrating signal, the dielectric medium and the ground having substantially the same dielectric properties.

19. The detector of claim 17, wherein the at least one transducer is configured to transmit the ground-penetrating signal to the object positioned in the ground and receive a reflection signal of the ground-penetrating signal from the object.

20. The detector of claim 19, further including a processor configured to calculate a distance between the at least one transducer and the object based on a time delay between the transmission of the ground-penetrating signal and the reception of the reflection signal.

21. The detector of claim 19, further including a processor configured to characterize the object based on the reflection signal.

22. The detector of claim 19, wherein the at least one transducer includes a first transducer that transmits the ground-penetrating signal to the object and a second transducer that receives the reflection signal from the object, wherein the first transducer is coupled to a first tooth of the work tool and the second transducer is coupled to a second tooth of the work tool.

23. The detector of claim 17, wherein the ground-penetrating signal is an electromagnetic signal.

24. The detector of claim 17, wherein the antenna includes a conducting plate positioned in a first plane and a ground plate positioned in a second plane.

25. A method of detecting an object positioned in the ground including the steps of:

providing a work tool and a detector mounted to the work tool that communicates a ground-penetrating signal between the object and the detector, the work tool being configured to penetrate the ground, the detector forming a leading cutting edge of the work tool and including a transmitting antenna and an array of receiving antennas each mounted along the leading cutting edge of the work tool, the detector including a dielectric medium substantially encapsulating the transmitting antenna and the array of receiving antennas and forming the leading cutting edge of the work tool, the transmitting antenna being configured to transmit the ground-penetrating signal and the array of receiving antennas being configured to detect a reflection signal of the ground-penetrating signal from the object;

penetrating the ground with the work tool to create a penetration;

positioning at least a portion of the detector in the penetration; and

detecting the object with the detector while the at least a portion of the detector is located in the penetration.

26. The method of claim 25, wherein the positioning step is simultaneous with the penetrating step.

27. The method of claim 25, further including the step of determining a distance between the detector and the object based on a time delay between the transmission of the ground-penetrating signal and the reception of the reflection signal.

28. The method of claim 25, further including the step of characterizing the object based on the reflection signal.

29. The method of claim 25, wherein the transmitting antenna includes an antipodal Vivaldi antenna that transmits the ground-penetrating signal to the object and the array of receiving antennas includes discone antennas that receive the reflection signal from the object.

30. The method of claim 25, wherein the dielectric medium contacts the ground during the communication of the ground-penetrating signal, and the dielectric medium and the ground having substantially the same dielectric properties.

31. The method of claim 25, further including the step of using construction equipment to move the work tool during the penetrating step, the construction equipment including:

a chassis;

a plurality of traction devices positioned to support the chassis; and

a propulsion device supported by the chassis and configured to move the work tool during the penetrating step to create the penetration,

the detector being positioned below the propulsion device during the penetrating step.

32. The method of claim 25, wherein the ground-penetrating signal is an electromagnetic signal.

33. A method of reducing signal loss in the detection of an object positioned in the ground, including the steps of:

providing a work tool configured to penetrate the ground, the work tool including a tooth;

providing a detector having at least one transducer and a dielectric medium, the detector being mounted to the work tool, the dielectric medium of the detector forming an outer profile of the tooth and substantially encapsulating the at least one transducer, the at least one transducer including an array of discone antennas operative to detect a ground-penetrating signal;

placing the detector in contact with the ground so that the dielectric medium is positioned between the at least one transducer and the ground; and

communicating a ground-penetrating signal through the dielectric medium between the at least one transducer and the ground to substantially reduce signal loss.

34. The method of claim 33, wherein the at least one transducer further includes a transmitting antenna configured to transmit the ground-penetrating signal to the object positioned in the ground, and the array of discone antennas are operative to receive a reflection signal of the ground-penetrating signal from the object.

35. The method of claim 33, wherein the dielectric medium contacts the ground, the dielectric medium and the ground having substantially the same dielectric properties.

36. The method of claim 33, wherein the dielectric medium forms a cutting edge of the tooth of the work tool.