Magnetometer Orientation Sensor for Marine Streamers

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Solution Overview

Problem

Existing orientation sensors in marine geophysical surveying equipment face challenges in accurately determining orientation due to overlaid linear acceleration and vibration, particularly at the head end of streamers, which affects the accuracy of orientation data.

Innovation Solution

The use of a complimentary orientation sensor, such as a magnetometer, in conjunction with an accelerometer, helps mitigate the effects of linear acceleration and vibration, providing more accurate orientation data by direct measurement of the geophysical surveying equipment's orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a DC-coupled accelerometer is used as an orientation sensor, then the orientation can be determined directly, but the measurement accuracy deteriorates due to overlaid linear acceleration and vibration

Engineering Contradiction:
Improveorientation measurement accuracyVSAvoidlinear acceleration and vibration interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent combines a magnetometer and an accelerometer into a unified orientation sensing system. The magnetometer measures the Earth's magnetic field to determine heading, while the accelerometer measures gravity to determine roll and pitch. By merging these complementary sensors, the system achieves accurate orientation measurement without being affected by linear acceleration interference, as each sensor type is insensitive to the harmful factors that affect the other.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The magnetometer acts as an intermediary sensor that provides orientation information independent of the accelerometer's vulnerability to linear acceleration. The magnetometer's measurement of the Earth's magnetic field serves as a reference that is not corrupted by vibration and linear acceleration, thereby mediating the overall orientation determination accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If an accelerometer is used at the head end of a streamer, then orientation data can be collected, but noise levels increase due to high linear acceleration

Engineering Contradiction:
Improveorientation data qualityVSAvoidnoise from linear acceleration
Core Design Contradiction:
Loss of informationVSObject-generated harmful factors

Solution Approach 1:

The patent merges a magnetometer with the accelerometer system at the streamer head end. The magnetometer provides clean orientation measurements that are not contaminated by the high linear acceleration noise present at this location. By combining both sensors, the system recovers high-quality orientation data despite the harsh acoustic environment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system changes the measurement parameters by using the magnetometer to measure the Earth's magnetic field vector instead of relying solely on accelerometer measurements. This parameter change allows orientation determination in environments where linear acceleration is high, as the magnetometer's measurement principle is fundamentally different and not affected by mechanical acceleration.

Inventive Principle:
Principle #35Parameter changes

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

This combination of sensors significantly reduces noise levels in orientation determination, enhancing the accuracy of orientation data during turns and in situations with significant vibration, leading to more reliable geophysical surveying results.

Implementation Method 1

the magnetometer measures a magnetic field, such as the Earth's magnetic field, with a magnetometer

Methodology Applied
Scientific EffectMagnetic field measurement: Magnetic Field

Implementation Method 2

A typical orientation sensor used with geophysical surveying equipment may be a DC-coupled accelerometer, such as a micro-electromechanical system (MEMS) accelerometer

Methodology Applied
Scientific EffectAcceleration measurement: Accelerometer

Data Source

PatentEP3086141B1Magnetometer as an orientation sensor
Publication Date: 2020.12.16 PGS GEOPHYSICAL AS
  • EP3086141B1 patent drawingFigure 1
  • EP3086141B1 patent drawingFigure 2~3
  • EP3086141B1 patent drawingFigure 4

AI summary

Included are methods and systems for marine geophysical surveying. A system includes a streamer (40); a sensor package (55) coupled to the streamer, wherein the sensor package comprises a primary orientation sensor (41) and a complimentary orientation sensor (42), wherein the complimentary orientation sensor comprises a magnetometer, wherein the primary orientation sensor and the complimentary orientation sensor are capable of collecting data indicative of the orientation of the streamer; and geophysical sensors (30) distributed on the streamer.