Underground Homing Control Using Dipole Field Feedback
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Solution Overview
Problem
Existing underground drilling systems face challenges in accurately guiding a drill head to a target location, particularly when drilling beneath obstacles, due to positional error accumulation and the limitations of traditional homing systems at long ranges.
Innovation Solution
A system that uses a time-varying dipole field transmitted by the boring tool, combined with a pitch sensor and a homing receiver, to generate accurate vertical and horizontal homing commands by compensating for measurement errors, allowing precise control of the drill head's depth and direction using a drill string length determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional steering tool systems are used to predict boring tool position step-by-step through numerical integration, then the system can operate without surface access, but positional error accumulates to unacceptable levels
Solution Approach 1:
The system employs a homing receiver that continuously receives electromagnetic signals from the boring tool and provides real-time feedback on the tool's position relative to the target. This feedback mechanism allows the system to correct for positional errors as they accumulate, rather than allowing them to compound unchecked through step-by-step numerical integration. The homing commands generated based on this feedback enable precise positioning even at long ranges.
Solution Approach 2:
The patent replaces the mechanical/mathematical integration system with an electromagnetic field-based homing system. Instead of relying on numerical integration of pitch and yaw angles through the ground, the system uses electromagnetic signals transmitted by the boring tool and received at the surface to directly determine position and generate homing commands, eliminating the error accumulation inherent in step-by-step mechanical integration.
2Measurement precision
If optical gyroscopes are used in inertial guidance systems to measure pitch and yaw with high precision, then measurement accuracy improves, but system cost increases significantly
Solution Approach 1:
The system replaces expensive optical gyroscopes and inertial guidance systems with a simpler electromagnetic homing system. The boring tool transmits electromagnetic signals that are received and processed to generate homing commands, eliminating the need for complex and costly inertial measurement devices while achieving comparable or superior positioning accuracy.
Solution Approach 2:
The boring tool serves its own positioning needs by transmitting electromagnetic signals that enable the surface receiver to determine its position and generate homing commands. This self-service approach eliminates the need for external expensive measurement systems like optical gyroscopes, as the tool itself provides the signal source for its own guidance.
3Ease of operation
If conventional homing systems are used to guide the boring tool to target, then the system is simpler to operate, but the effective range is limited and accuracy deteriorates at long distances
Solution Approach 1:
The system employs signal processing techniques that change key parameters of the electromagnetic signal transmission and reception. By optimizing signal frequency, power, and processing algorithms, the system extends the effective range of the homing system while maintaining accuracy. The patent specifically addresses long-range operation by modifying how signals are transmitted and processed to overcome attenuation and interference over distance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances drilling accuracy by reducing positional error accumulation and increasing the effective range of homing commands, enabling precise targeting even at longer distances.
Implementation Method 1
a transmitter, forming part of the boring tool, for transmitting a time varying dipole field as a homing field
Implementation Method 2
A homing receiver is positionable at least proximate to a target location for detecting the homing field to produce a set of flux measurements
Data Source
AI summary
A boring tool that is moved by a drill string to form an underground bore. A transmitter transmits a time varying dipole field as a homing field from the boring tool. A pitch sensor detects a pitch orientation of the boring tool. A homing receiver is positionable at a target location for detecting the homing field to produce a set of flux measurements. A processing arrangement uses the pitch orientation and flux measurements 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 the target location such that the vertical homing command is generated with a particular accuracy at a given range between the transmitter and the homing receiver and which would otherwise be generated with the particular accuracy for a standard range, different from the particular range. An associated system and method are described.