US 12,188,346 B2
Advanced underground homing system, apparatus and method
Guenter W. Brune, Bellevue, WA (US); John E. Mercer, Gig Harbor, WA (US); and Albert W. Chau, Woodinville, WA (US)
Assigned to Merlin Technology Inc., Kent, WA (US)
Filed by Merlin Technology Inc., Kent, WA (US)
Filed on Mar. 4, 2023, as Appl. No. 18/117,419.
Application 18/117,419 is a continuation of application No. 17/151,612, filed on Jan. 18, 2021, granted, now 11,598,198.
Application 17/151,612 is a continuation of application No. 16/161,043, filed on Oct. 15, 2018, granted, now 10,895,145, issued on Jan. 19, 2021.
Application 16/161,043 is a continuation of application No. 15/231,764, filed on Aug. 8, 2016, granted, now 10,107,090, issued on Oct. 23, 2019.
Application 15/231,764 is a continuation of application No. 13/761,632, filed on Feb. 7, 2013, granted, now 9,422,804, issued on Aug. 23, 2016.
Application 13/761,632 is a continuation of application No. 12/689,954, filed on Jan. 19, 2010, granted, now 8,381,836, issued on Feb. 26, 2013.
Prior Publication US 2023/0203938 A1, Jun. 29, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. E21B 47/0232 (2012.01); E21B 7/04 (2006.01); E21B 44/00 (2006.01); E21B 47/024 (2006.01)
CPC E21B 47/0232 (2020.05) [E21B 7/046 (2013.01); E21B 44/005 (2013.01); E21B 47/024 (2013.01)] 8 Claims
OG exemplary drawing
 
1. In a system including a boring tool that is moved by a drill string using a drill rig that selectively extends the drill string to the boring tool to form an underground bore such that the drill string is characterized by a drill string length which is determinable, a homing apparatus comprising:
a transmitter for transmitting a time varying dipole field as a homing field and including a pitch sensor for detecting a pitch orientation of the boring tool;
a receiver that is positionable at least proximate to a target location for detecting the homing field to produce a set of flux measurements;
a processor that is configured for using the detected pitch orientation and the set of flux measurements in conjunction with a determined length of the drill string to determine a vertical homing command for use in controlling depth in directing the boring tool to said target location such that the vertical homing command is generated with an accuracy at a given range between the transmitter and the receiver that is higher than another accuracy that would otherwise be generated without using the determined length of the drill string at the given range; and
a display for indicating said vertical homing command to a user.