Airborne EM Survey Rigid Loop Nulling Primary Field Interference
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Solution Overview
Problem
Airborne electromagnetic survey systems face challenges in minimizing noise from primary electromagnetic fields, which overwhelm receivers and interfere with secondary field detection, leading to unreliable geological data. Existing solutions either require large, heavy structures for rigidity or flexible designs prone to vibration noise.
Innovation Solution
A rigid transmitter loop structure with dual turn receiver coils and helical coils positioned close to the transmitter to null out the primary electromagnetic field, allowing for precise measurement of vertical and horizontal components of the secondary field while minimizing size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the receiver is physically separated from the transmitter by housing it in a bird, then the interference from the primary electromagnetic field is reduced, but the receiver position changes relative to the transmitter and detects much of the primary field
Solution Approach 1:
A rigid transmitter loop structure serves as an intermediary between the transmitter and receiver, maintaining a fixed geometric relationship that allows the receiver to be positioned close to the transmitter while still minimizing primary field interference through controlled geometry
Solution Approach 2:
The system is divided into separate functional components (transmitter, receiver, and rigid loop structure) that can be independently optimized while maintaining their relative positions through the rigid structure
2Reliability
If a rigid transmitter loop structure is used to maintain constant geometry, then noise from vibration is reduced, but the structure becomes larger and heavier
Solution Approach 1:
The rigid loop structure utilizes three-dimensional geometric configuration to achieve rigidity and noise reduction without requiring excessive material mass, optimizing the shape and spatial arrangement of the loop segments
Solution Approach 2:
The transmitter loop structure employs composite construction combining rigid materials with appropriate density characteristics to achieve maximum structural rigidity while minimizing overall weight
3Weight of moving object
If the receiver is positioned close to the transmitter, then the size and weight of the system is reduced, but the primary electromagnetic field overwhelms the receiver
Solution Approach 1:
The rigid transmitter loop structure acts as a geometric intermediary that enables close positioning of the receiver to the transmitter while maintaining a configuration that minimizes primary field coupling through controlled loop geometry
Solution Approach 2:
The system optimizes geometric parameters of the transmitter loop structure, including loop size, shape, and orientation, to achieve the optimal balance between minimizing primary field interference and allowing close receiver-positioning for weight reduction
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 solution effectively reduces vibratory noise and interference, enabling more accurate geological data collection with a compact and lightweight system capable of completely canceling the primary field signal.
Implementation Method 1
transmitting means fitted to at least one of the interconnected loop segments for generating and transmitting an earthbound primary electromagnetic field
Implementation Method 2
sensing means fitted to at least one of the interconnected loop segments for receiving and sensing a vertical component of a secondary resulting electromagnetic field, the secondary resulting field arising from an interaction of the primary electromagnetic field with ground bodies
Implementation Method 3
dual turn receiver coils to null out the primary electromagnetic field signal emitted by the transmitter, while still measuring a vertical component of the secondary electromagnetic field, and utilizes helical coils, in close proximity to the transmitter, oriented and connected to null out the primary electromagnetic field signal
Data Source
AI summary
An airborne electromagnetic survey system for conducting geological mapping is disclosed. A transmitter closed loop structure is used in the system and is designed for connection to a towing airborne vehicle. The transmitter loop structure comprises a plurality of interconnected loop segments, and transmitting means are fitted to at least one of the loop segments for generating and transmitting an earthbound primary electromagnetic field effective for geological surveying. Sensing means are fitted to the loop segments for receiving and sensing a vertical component of a secondary resulting electromagnetic field which arises from an interaction of the primary electromagnetic field with ground bodies that are traversed by the sensing means, while simultaneously nulling the primary electromagnetic field. Helical sensing means are positioned in close proximity to the transmitting means to receive and sense a horizontal electromagnetic field contained in the secondary resulting field, while simultaneously nulling the primary electromagnetic field.