Sonar Target Detection Using Pulse Train Correlation
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Solution Overview
Problem
Continuous active sonar sonobuoys face limitations due to cross-channel interference and restricted detection regions, which hinder effective detection and localization of underwater targets.
Innovation Solution
A target detection system comprising multiple sources and receivers configured to transmit and receive pulse trains of identical pulses within an underwater detection region, utilizing a data processor to differentiate between target and source pulses through correlation data analysis, thereby reducing interference and expanding detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple continuous active sonar sonobuoys are deployed to expand detection region, then detection coverage is improved, but cross-channel interference increases
Solution Approach 1:
The system segments the detection region into multiple channels, each monitored by dedicated sonobuoys. By organizing sonobuoys into distinct channels with specific geographic coordinates, the system can manage and control interference patterns across different spatial segments, allowing expansion of total detection coverage while managing cross-channel effects through structured segmentation.
Solution Approach 2:
The processor acts as an intermediary that receives signals from multiple sonobuoys, generates correlation data, and distinguishes between target echoes and cross-channel interference. By introducing this intermediate processing layer that analyzes temporal and spatial correlations, the system can differentiate useful target signals from harmful interference, enabling deployment of more sonobuoys without proportionally increasing interference impact.
2Duration of action of moving object
If pulse wave duty cycle is increased to improve detection continuity, then detection capability is improved, but interference from multiple sources increases
Solution Approach 1:
The system employs periodic pulse trains with specific repetition frequencies from multiple sonobuoys. By using periodic action with carefully controlled pulse repetition intervals, the system creates predictable interference patterns that can be distinguished from target echoes through correlation analysis. This allows continuous duty cycle operation while maintaining the ability to differentiate between periodic source signals and aperiodic target reflections.
Solution Approach 2:
The processor generates correlation data by comparing received signals against expected pulse train patterns from known source locations. This feedback mechanism continuously monitors signal correlations and uses the results to distinguish between direct source pulses and target echoes, enabling the system to maintain high duty cycle operation while compensating for cross-channel interference through real-time correlation-based discrimination.
3Measurement precision
If correlation data analysis is used to distinguish target pulses from source pulses, then target detection accuracy is improved, but processing complexity increases
Solution Approach 1:
The system replaces complex mechanical or manual signal analysis methods with automated electronic correlation processing. By using digital signal processing techniques that automatically compute correlation data between received signals and known source pulse patterns, the system achieves high detection accuracy without requiring complex manual intervention. The electronic correlation method systematically processes signals through standardized algorithms, improving precision while keeping processing complexity manageable through automation.
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 system enhances target detection accuracy and expands the detection region, allowing for more effective navigation and surveillance by distinguishing between source and target pulses, thereby improving the overall performance of sonar systems.
Implementation Method 1
Each of the number of sources is configured to transmit a sound wave underwater within the underwater detection region
Implementation Method 2
An active sonobuoy emits sound in the form of a pulse wave into the water and listens for the returning echo
Implementation Method 3
The data processor is configured to generate correlation data for the pulses in response to receiving the data from the receiver
Data Source
AI summary
A method and apparatus for detecting targets. A sound wave within an underwater detection region is transmitted from each of a number of sources. The sound wave transmitted by each of these sources comprises a pulse train of identical pulses. Pulses are received at a receiver within the underwater detection region. Data is generated in response to receiving the pulses. Correlation data for the pulses is generated based on the data generated by the receiver. A determination is made as to whether each of the pulses received at the receiver is received from a target located within the underwater detection region or from one of the number of sources.