Compact Dual Beam Vector Sensor for Underwater Directional Sensitivity

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Solution Overview

Problem

Existing acoustic sensors for underwater applications are limited by their size, weight, and noise rejection capabilities, particularly in determining the direction of sound waves, as they often require multiple hydrophones and complex signal processing to achieve directional sensitivity, which increases cost and complexity.

Innovation Solution

A compact dual beam vector sensor design is developed, featuring orthogonally mounted vector sensors within a neutrally buoyant housing, utilizing piezoelectric crystalline plates and a proof mass to measure three components of acceleration with high sensitivity and low noise, reducing component count and cost while maintaining performance across a wide frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If omnidirectional hydrophones are used to measure pressure field, then the sensor can detect acoustic pressure, but the sensor cannot determine the direction of sound waves without multiple hydrophones and complex signal processing

Engineering Contradiction:

Improvedirectional sensitivityVSAvoidnumber of hydrophones and signal processing algorithms

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines pressure sensing and particle velocity sensing into a single vector sensor unit. The sensor integrates a pressure transducer with three orthogonal accelerometers (or velocity sensors) to measure all components of the acoustic vector at one location, eliminating the need for multiple omnidirectional hydrophones and complex beamforming algorithms while providing inherent directional information

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The vector sensor is designed to perform multiple functions simultaneously: it measures acoustic pressure, particle velocity in three orthogonal directions, and inherently determines sound direction. This multi-functional approach replaces the need for separate omnidirectional sensors and post-processing algorithms, reducing overall system complexity while improving directional measurement capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If directional sensor is used to improve noise rejection, then the signal-to-noise gain increases by a factor of two, but the sensor size and weight increase

Engineering Contradiction:

Improvenoise rejection capabilityVSAvoidsensor weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The sensor is divided into functionally independent modules: a pressure transducer element and three orthogonal accelerometer elements. Each element is miniaturized and operates independently, allowing the overall sensor to achieve directional sensitivity and noise rejection without requiring a large physical structure. The segmented design enables compact integration while maintaining the noise rejection benefits of directional sensing

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If vector sensor array is assembled to improve spatial filtering capabilities, then the directional detection improves, but the cost and manufacturing complexity increase

Engineering Contradiction:

Improvespatial filtering capabilityVSAvoidmanufacturing cost and complexity

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the functionality of multiple omnidirectional hydrophones into a single vector sensor that provides equivalent or superior spatial filtering capability. By integrating pressure and velocity sensing in one unit, the system achieves the same array performance with fewer elements, reducing manufacturing cost, assembly complexity, and calibration requirements while improving directional detection

Inventive Principle:

Principle #5Merging (Combining)

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 compact dual beam vector sensor design enhances signal-to-noise gain by a factor of two compared to omnidirectional sensors, offering improved directional sensitivity and reduced size, weight, and cost, while maintaining consistent and repeatable performance over the desired frequency range.

Implementation Method 1

utilizing piezoelectric crystalline plates and a proof mass to measure three components of acceleration

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

A pair of dual beam vector sensors are mounted orthogonally to each other in the housing interior with the housing being neutrally buoyant

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS11313875B1Compact dual beam vector sensor

Publication Date: 2022.04.26 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES

AI summary

A pair of vector sensors are provided and mounted orthogonally to each other. Each vector sensor includes a central structural member having a first end and a second end. The central structural member has four symmetric arms oriented at 90° to each other. A crystalline plate is attached perpendicular to a distal end of each arm of the central structural member. The first end of each vector sensor is embedded in a socket of a proof mass. The second end of each vector sensor is embedded in an aperture of a cubic base.