Bottom-Weighted Platform for Low-Frequency EM Data Acquisition
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Solution Overview
Problem
Current airborne electromagnetic survey systems face challenges in acquiring low-frequency data below 25 Hz due to high motion noise, which limits the detection of deep geological features, as they require sensitive magnetic field measurements in the presence of a strong static magnetic field, and existing orientation stabilization methods introduce vibrational noise.
Innovation Solution
A system with a bottom-weighted instrument platform mounted on a spherical bearing that allows free angular rotation, decoupling the platform from carrier motions and using a righting system to minimize angular velocity and orientation errors, thereby reducing motion noise and enhancing data quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional orientation stabilization methods are used, then rotational motion is limited, but vibrational noise is introduced that contaminates measurements
Solution Approach 1:
The patent extracts the stabilization function from active control systems and replaces it with a passive mechanical design. The bottom-weighted platform configuration inherently provides rotational stability through gravity without requiring active stabilization mechanisms that generate vibrational noise.
Solution Approach 2:
The patent applies the counterweight principle by positioning heavy components at the bottom of the platform. This bottom-weighted configuration creates a stable pendulum-like structure that naturally resists rotational motion and returns to equilibrium position, eliminating the need for active stabilization systems.
2Measurement precision
If low frequency EM data acquisition is attempted, then deep geological features become detectable, but motion noise increases significantly
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the platform with bottom-weighted stability before data acquisition begins. This passive stabilization is in place before low-frequency measurements start, preventing motion noise from contaminating the sensitive measurements rather than attempting to correct it afterward.
3Duration of action of moving object
If the measurement duration is increased to improve low frequency data quality, then rotational stability requirements become more stringent
Solution Approach 1:
The patent applies self-service by designing a platform that automatically maintains its own rotational stability through passive gravitational forces. The bottom-weighted configuration creates a self-correcting mechanism that continuously returns the platform to equilibrium without external intervention, enabling long-duration measurements.
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 system effectively suppresses motion noise within the acquisition band, allowing for high-quality electromagnetic data acquisition at low frequencies, improving the detection of deep geological features and reducing contamination from vibrational noise.
Implementation Method 1
a spherical bearing mounted to the base assembly; an instrument platform having at least one vector component sensor fixed thereto, the instrument platform being mounted on and supported by the spherical bearing, the spherical bearing thereby coupling the instrument platform to the base assembly and allowing free angular rotation
Implementation Method 2
Noise in an electromagnetic measurement caused by the rotation of a vector component EM sensor in the background static magnetic field of the Earth may be referred to as motion noise. The instrument platform has a center of mass disposed below the center of rotation, suppressing motion noise within an acquisition band of the at least one vector component sensor
Implementation Method 3
The electrical properties of the Earth may be inferred by measuring the time variation of the magnetic field set up by this current with a magnetic field sensor
Implementation Method 4
measuring the time variation of the magnetic field set up by this current with a magnetic field sensor
Implementation Method 5
using a righting system to minimize angular velocity and orientation errors, thereby reducing motion noise and enhancing data quality
Data Source
AI summary
Aspects of the disclosure may reduce motion noise by mounting vector component sensors on a bottom-weighted instrument platform that is supported with a spherical bearing. An apparatus for data acquisition is provided. The apparatus includes a base assembly, a spherical bearing mounted to the base assembly, and an instrument platform having at least one vector component sensor fixed thereto. The instrument platform is mounted on and supported by the spherical bearing. The spherical bearing couples the instrument platform to the base assembly and allows free angular rotation of the instrument platform, within a tilt angle range. The instrument platform is bottom weighted in that it has a center of mass disposed below its center of rotation. The apparatus may include a controller that receives and/or stores data from the at least one sensor.