Receiver using an approximated dipole signal

• US 9,581,717 B2
• Filed: 02/21/2014
• Issued: 02/28/2017
• Est. Priority Date: 11/15/2001
• Status: Expired due to Fees

• Current Assignee: Merlin Technologies Incorporated
• Original Assignee: Merlin Technologies Incorporated
• Inventors: Brune, Guenter W., Mercer, John E., Chau, Albert W., Zeller, Rudolf
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US14/186,310
• Publication Number:
  US 20140167764A1
• Time in Patent Office: 1,103 Days
• Field of Search: 324326-329, 175/45
• 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: H01Q 1/04 Adaptation for subterranean or subaqueous use
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00

Abstract

Location determination is performed using a transmitter including an elongated generally planar loop antenna defining an elongation axis. The elongation axis is positioned along at least a portion of a path. A magnetic field is then generated which approximates a dipole field. Certain characteristics of the magnetic field are then determined at a receiving position radially displaced from the antenna elongation axis. Using the determined certain characteristics, at least one orientation parameter is established which characterizes a positional relationship between the receiving position and the antenna on the path. The magnetic field may be transmitted as a monotone single phase signal. The orientation parameter may be a radial offset and/or an angular orientation between the receiving position and the antenna on the path. The antenna of the transmitter may be inserted into a first borehole to transmit the magnetic field to a receiver inserted into a second borehole.

Claims

1. A receiver assembly for use in an apparatus for location determination, said receiver assembly comprising:

a receiver for detecting characteristics of an electromagnetic field that approximates a dipole signal in two dimensions as emanated from an elongated transmitter defining a transmitter elongation axis by measuring the electromagnetic field at a receiving position radially displaced from the transmitter elongation axis; and

a processor forming part of the receiver for determining an orientation parameter, based on a flux pattern for an approximated dipole signal in a plane that is orthogonal to the transmitter elongation axis, which characterizes the receiving position relative to the transmitter elongation axis based on the measured electromagnetic field.

2. The receiver assembly of claim 1 wherein said orientation parameter is a radial offset from the transmitter elongation axis to the receiving position.

3. The receiver assembly of claim 1 wherein said orientation parameter is an angular orientation of the receiving position relative to the transmitter elongation axis.

4. The receiver assembly of claim 1 wherein said receiver includes a width that provides for insertion of the receiver into a borehole.

5. The receiver assembly of claim 1, further comprising:

a pair of sensors spaced apart to cooperatively define a receiving axis with each sensor detecting the characteristics of the electromagnetic field corresponding to a different position along the receiving axis; and

said processor further configured for determining at least a yaw value between the transmission axis and the receiving axis of the receiver based on the measured electromagnetic field.

6. The receiver assembly of claim 5 wherein a first one of said sensors detects the electromagnetic field along three orthogonally oriented axes and a second one of said sensors detects the electromagnetic field along at least an axis that is at least generally transverse to the receiving axis.

7. The receiver assembly of claim 5 wherein said receiver includes a width that provides for insertion of the receiver into a borehole.

8. The receiver assembly of claim 1 configured to determine the orientation parameter based on no more than the measured electromagnetic field that approximates a dipole signal in two dimensions.