Self-Calibrating Coil Array for Underground Service Depth Detection
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Solution Overview
Problem
Existing cable detection devices for locating underground services are prone to inaccuracies due to environmental influences and mechanical tolerances, leading to low accuracy in depth determination, and require external calibration which may not be feasible in field conditions.
Innovation Solution
A mobile detection device with self-calibration capabilities, using a method where coils can be configured as transmitters to emit a calibration field, allowing for the determination of calibration parameters without external equipment, and can be resized for compact storage and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external calibration equipment is used to calibrate the detection device, then measurement precision can be improved, but device complexity and ease of operation worsen due to requiring additional external equipment and calibration procedures
Solution Approach 1:
The detection device performs self-calibration by using its own coils as both transmitters and receivers. The calibration unit configures one coil as a transmitter emitting a calibration field, while another coil acts as receiver to detect the field. This self-contained approach eliminates the need for external calibration equipment, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The coils in the detection device serve multiple functions: they can operate as receivers for detecting underground services during normal operation, and as transmitters for emitting calibration fields during calibration mode. This multi-functionality allows the device to perform both detection and calibration without requiring separate dedicated components, reducing overall system complexity while maintaining calibration accuracy.
2Ease of operation
If the detection device is made lightweight and small-sized for portability, then ease of operation improves, but manufacturing precision and stability worsen due to mechanical tolerances and environmental influences
Solution Approach 1:
The calibration process measures the actual characteristics of each coil (such as position and response) and uses this feedback information to determine individual calibration parameters for each coil. This feedback mechanism compensates for manufacturing tolerances and environmental variations, allowing the device to maintain high measurement precision despite being lightweight and portable.
Solution Approach 2:
The system determines individual calibration parameters for each coil based on measured characteristics, effectively adjusting the operational parameters to compensate for physical variations. By changing the electrical parameters (calibration factors) based on measured physical states, the system compensates for mechanical tolerances without requiring tighter manufacturing specifications.
3Measurement precision
If individual calibration parameters are determined for each coil to compensate for variations, then measurement precision improves, but device complexity increases due to additional calibration procedures
Solution Approach 1:
The calibration unit automatically performs the calibration procedure by configuring coils as transmitters and receivers in sequence, measuring their characteristics, and determining calibration parameters without requiring external equipment or complex manual procedures. This automated self-calibration approach improves measurement precision while keeping the user-facing complexity low.
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
The device achieves robust and accurate depth determination of underground services by compensating for mechanical and environmental variations, enabling reliable field calibration and high accuracy in depth measurement.
Implementation Method 1
a method for a mobile detection device (1) with multiple coils (2a, 2b, 2c) for determining a distance value from the detection device (1) to an occluded ac-current carrying structure (10), wherein a calibration of the detection device (1) comprises: applying an electrical excitation signal to one of the coils (2a, 2b, 2c), which configures the one coil as transmitter for a calibration field, and detecting the calibration field by at least two other coils (2a, 2b, 2c), to which the excitation signal is not applied
Implementation Method 2
mobile detection device (1) with multiple coils (2a, 2b, 2c) for determining a distance value from the device (1) to an occluded ac-current carrying structure (10) according to its emanated magnetic field
Data Source
Figure 1~2b
Figure 3a~4c
Figure 5
AI summary
The invention relates to a mobile detection device (1) for an evaluation of a distance value from the device to an occluded ac-current carrying structure according to its emanated magnetic field, like a location of underground services. The device comprises multiple detection coils (2a,2b) arranged with a spacing (3) with respect to one another and an electronic signal evaluation unit for detecting the structure according to an electrical signal induced in the detection coils (2a,2b) by the magnetic field and to evaluate the distance value according to a difference of the electrical signal in-between at least two of the detection coils (2a,2b). According to the invention, the device (1) comprises a calibration unit built to configure one of the detection coils (2a,2b) as transmitter for a calibration field (At,Bt) by applying an electrical excitation signal, which calibration field (At,Bt) is detected by the remaining of the detection coils (2a,2b) and whereof calibration parameters for the detection coils (2a,2b) are determined.