Piezoelectric Sensor System for Marine Seismic Noise Cancellation

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Solution Overview

Problem

Existing sensors for mapping strata beneath water bodies are limited by sensitivity to noise sources and bandwidth constraints, particularly due to interference from noise sources like turbulent boundary layers and surface reflections.

Innovation Solution

A piezoelectric sensor system is developed, incorporating a liquid metal electrode and a microsphere-loaded transfer adhesive, which allows for dual-output seismic surveys by separating responses to dynamic pressure and mechanical forces, enhancing signal-to-noise ratio and bandwidth through noise cancellation techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional hydrophone sensors are used to map strata beneath water bodies, then basic acoustic detection is achieved, but the sensors exhibit high sensitivity to noise sources and limited bandwidth

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidnoise sensitivity

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent combines a motion sensor (accelerometer) and an acoustic sensor (hydrophone) into a single integrated apparatus. The motion sensor detects particle motion while the acoustic sensor detects acoustic pressure, and their signals are combined to produce an output that rejects noise from turbulent boundary layers and surface reflections, thereby improving signal-to-noise ratio and bandwidth

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent converts the harmful effect of turbulent boundary layer noise and surface reflections into a beneficial signal processing opportunity. By using the motion sensor to detect the same noise sources that affect the acoustic sensor, the system can identify and reject these harmful signals, transforming what was previously detrimental noise into useful information for noise cancellation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If a single acoustic sensor is used, then device complexity is minimized, but bandwidth and noise rejection capabilities are limited

Engineering Contradiction:

ImprovebandwidthVSAvoidsensor configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The integrated apparatus performs multiple functions simultaneously: the motion sensor measures particle acceleration, the acoustic sensor measures acoustic pressure, and the signal processing combines these measurements to achieve both broadband response and noise rejection. This multi-functionality expands the effective bandwidth while managing device complexity through integration

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11163078B2Combination motion and acoustic piezoelectric sensor apparatus and method of use therefor

Publication Date: 2021.11.02 SEAMAP USA LLC

AI summary

Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first sensor is a motion sensor including a conductive liquid in a chamber between a rigid tube and a piezoelectric motion film circumferentially wrapped about the tube. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using a piezoelectric sensor mounted with a thin film separation layer of flexible microspheres on a rigid substrate. Additional non-acoustic sensors are optionally mounted on the rigid substrate for generation of output used to reduce noise observed by the acoustic sensors. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.