Sonobuoy Acoustic Source Identification Using Wavelet Denoising and CNN

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Solution Overview

Problem

Identifying submarine signals in noisy marine environments is challenging due to sound distortion and interference from dense water layers, subsurface features, and background noise, making it difficult to detect and locate submarines using sonobuoys.

Innovation Solution

The method employs wavelet denoising to minimize background noise, followed by autocorrelation for signal enhancement, and uses a convolutional neural network (CNN) for signal source isolation and classification, enabling accurate and automated detection and geolocation of submarines in noisy environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional noise reduction methods are used, then background noise can be reduced, but the processing time increases and transient signals are lost

Engineering Contradiction:
Improvebackground noiseVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical signal averaging methods with wavelet transform-based denoising. Wavelet transform provides a mathematical framework that can separate signal and noise in the time-frequency domain, achieving noise reduction without requiring multiple signal acquisitions or lengthy processing times. This substitution of mathematical transformation for mechanical averaging resolves the contradiction between noise reduction and processing time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter domain from time-domain averaging to time-frequency domain analysis using wavelet transforms. By transforming the signal into different resolution levels, the method can selectively preserve transient features while removing noise, achieving both noise reduction and preservation of transient signals without increased processing time.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If signal processing is performed to identify submarine signals, then detection accuracy improves, but the complexity of the processing system increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the signal processing into distinct stages: wavelet denoising, autocorrelation enhancement, and CNN classification. Each stage handles a specific aspect of signal processing, making the overall complex system manageable through modular organization. This segmentation allows high detection accuracy to be achieved while controlling system complexity through structured processing steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces autocorrelation as an intermediary processing step between wavelet denoising and CNN classification. This intermediary enhances the signal characteristics by emphasizing periodic patterns while suppressing random noise, bridging the gap between raw signal processing and machine learning classification, and improving overall detection accuracy without requiring direct complex interactions between all processing components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple sonobuoys are used for geolocation, then submarine location accuracy improves, but the cost and system complexity increase

Engineering Contradiction:
Improvegeolocation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes each sonobuoy multi-functional by equipping it with both passive acoustic monitoring capabilities and onboard signal processing (wavelet denoising and autocorrelation). This allows individual sonobuoys to perform multiple functions independently, reducing the need for complex centralized processing and making the deployment of multiple units more cost-effective while maintaining geolocation accuracy through distributed processing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11769045B2Method to identify acoustic sources for anti-submarine warfare
Publication Date: 2023.09.26 NOKOMIS INC
  • US11769045B2 patent drawing
  • US11769045B2 patent drawing
  • US11769045B2 patent drawing

AI summary

A method to detect the presence and location of submarines in a complex marine environment by wavelet denoising, wavelet signal enhancement, by autocorrelation and signal source identification a convolutional neural network.