Spiral Sonar Head Reduces Channel Count for Real-Time Target Detection
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Solution Overview
Problem
Conventional single-ping active sonar systems require a large number of channels to achieve resolution, leading to increased system complexity and cost, while multi-ping sonars do not operate in real time and need to retain significant data for image reconstruction.
Innovation Solution
The spiral wave front sonar transmits a spiral signal with varying phase and a constant reference signal, allowing for range and aspect determination using as few as three channels, with the backscattered return decoded from a single channel hydrophone, reducing hardware and data acquisition complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-ping active sonar uses a large number of channels to achieve resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the waveform parameter from conventional signals to spiral waveforms with specific phase progression characteristics. This parameter change allows the system to achieve the same measurement precision with fewer channels, as the spiral phase information encodes spatial information more efficiently than conventional waveforms
Solution Approach 2:
The patent replaces the mechanical/approach of using more physical channels (hydrophones) with a signal processing approach using spiral waveforms. Instead of increasing hardware complexity, the invention substitutes a sophisticated waveform design that achieves the same resolution goal through acoustic signal characteristics rather than spatial aperture
2Device complexity
If conventional multi-ping active sonars use fewer channels, then device complexity is reduced, but productivity decreases due to non real-time operation
Solution Approach 1:
The patent employs periodic spiral waveforms with specific temporal characteristics that enable real-time processing. The periodic nature of the spiral signals allows for continuous operation and real-time detection, unlike multi-ping systems that require data accumulation over multiple pings
Solution Approach 2:
The spiral waveform design incorporates all necessary spatial encoding information in advance within the waveform structure itself. This preliminary encoding of spatial information in the transmitted signal allows immediate processing and real-time detection without requiring subsequent data accumulation or complex reconstruction algorithms
3Measurement precision
If conventional multi-ping active sonars retain large amounts of data for reconstruction, then measurement precision is improved, but loss of time increases due to data retention requirements
Solution Approach 1:
The patent extracts the essential spatial information directly from the spiral phase information in the received signal. By using spiral waveforms, the system extracts position information from the phase characteristics of the returned signal, eliminating the need to retain large amounts of raw data for subsequent reconstruction
Solution Approach 2:
The spiral waveform acts as an intermediary that carries spatial information in its phase structure. This intermediary encoding method allows the system to obtain precise position information directly from the signal phase without requiring extensive data retention or complex post-processing reconstruction
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
This approach enables real-time operation with reduced complexity and cost, outperforming conventional sonars in sparse environments, and is applicable in various underwater and in-air applications such as obstacle avoidance and target detection.
Implementation Method 1
transmitting a spiral signal whose phase varies by 2π over the transducer's azimuthal plane
Implementation Method 2
The backscattered return is decoded from a single channel hydrophone
Data Source
AI summary
An apparatus including a uniplanar sonar head. The uniplanar sonar head includes at least one probe element being configured to output cooperatively a unipolar spiral probe signal. The uniplanar sonar head includes at least one reference element being configured to output a circular reference signal. The uniplanar sonar head includes an acoustic receiver comprising an input channel being configured to receive a reflected unipolar spiral probe signal and a reflected circular reference signal. The apparatus includes a plurality of amplifiers communicating with the at least one probe element, the at least one reference element, and the acoustic receiver. The apparatus includes a processor cooperating with the plurality of amplifiers. The apparatus includes a computer-readable medium storing instructions including a target-detection method, which includes determining an angular position of the target based on the plurality of acoustic echoes received via the input channel.