Stackable Acoustic Horn Array for Multi-Target Detection

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Solution Overview

Problem

Existing directional microphones have limited range and are unable to simultaneously listen to multiple targets due to their mechanical pointing requirements and inability to be assembled into arrays, leading to high costs for digital beamforming solutions.

Innovation Solution

A stackable acoustic horn design that allows multiple horns to be configured into an array, increasing listening distance and enabling electronic beamforming to focus on multiple targets simultaneously, with each horn featuring a decreasing interior area from mouth to throat and a microphone positioned within the throat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If directional microphones (parabolic dishes, shotgun microphones) are used to capture sound from a target, then the listening distance is improved, but the device cannot be assembled into an array and must be mechanically pointed, limiting the ability to simultaneously listen to multiple targets

Engineering Contradiction:

Improvelistening distanceVSAvoidability to simultaneously listen to multiple targets

Core Design Contradiction:

Length of stationary objectVSAdaptability or versatility

Solution Approach 1:

The system divides the single large directional microphone function into multiple smaller identical horn elements that can be arranged in an array. Each horn element contributes to the overall directional sensitivity through constructive interference, enabling both long listening distance and multi-target capability simultaneously

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple identical horn elements are combined into an array configuration where their acoustic fields overlap and interfere constructively in the desired direction. This merging of individual horn responses creates a composite directional pattern that achieves both extended listening distance and multi-target detection capability

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple omnidirectional microphones are used in an array to achieve digital beamforming, then the ability to listen in multiple directions is improved, but the cost becomes prohibitive and the array requires large spacing that limits beamforming capability

Engineering Contradiction:

Improveability to listen in multiple directionsVSAvoidcost and spatial requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system changes the fundamental parameter of the microphone element from omnidirectional to highly directional horn-type sensitivity. This parameter change enables achieving the same beamforming capability with fewer, more closely spaced elements, reducing both cost and spatial requirements while maintaining multi-directional listening capability

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If directional microphones with narrow beams are used, then the sound separation capability is improved, but the devices cannot be placed close to each other due to spatial aliasing constraints

Engineering Contradiction:

Improvesound separation capabilityVSAvoidspacing between microphones

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The system replaces the mechanical constraint of physical spacing with an acoustic field-based solution. By using horn elements with inherently narrow beams that can be placed close together, the system achieves sound separation through acoustic interference patterns rather than requiring large mechanical spacing, eliminating spatial aliasing constraints

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 stackable horn array significantly enhances listening distance, allowing detection of sounds up to fifty times farther than a single microphone, while providing broad beamforming capabilities without spatial aliasing constraints, enabling simultaneous tracking and identification of multiple targets.

Implementation Method 1

Each horn diminishes in interior area from a mouth to a throat thereof... The horn or array may be secured to a support. An aperture is defined in the throat of the horn and a microphone is positioned inside the aperture

Methodology Applied

Scientific EffectAcoustic focusing: Focusing

Data Source

PatentUS10531185B1Stackable acoustic horn, an array of stackable acoustic horns and a method of use thereof

Publication Date: 2020.01.07 BAE SYSTEMS INFORMATION ANDELECTRONIC SYSTEMS INTEGRATION INC

AI summary

A stackable horn configured such that a plurality of substantially identical horns can be stacked to form an array. Each horn diminishes in interior area from a mouth to a throat thereof and is vertically taller and longitudinally deeper than it is wide. The horn or array may be secured to a support. In the array, the horns are similar or identical and are arranged side-by-side with a space in between or in abutting contact. An aperture is defined in the throat of each horn and a microphone is positioned within the throat of each horn in the array. The arrangement of horns in the array permits beamforming and as a result allows simultaneous detection, tracking, and identification of multiple targets. Listening distance is greatly increased by utilizing the horn or the array of horns.