Hyperspectral Sonar For Post-Processing Frequency Selection
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Solution Overview
Problem
Existing sonar systems, including broadband systems, are inadequate for comprehensive sea floor and water column classification due to limited frequency range and beam resolution, requiring prior knowledge of frequencies of interest and using multiple sonar systems or matched filters.
Innovation Solution
A hyperspectral sonar system utilizing a single system with broadband waveforms, beamforming, and post-processing methods to acquire data across a broad frequency range, enabling flexible post-processing frequency selection without matched filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sonar systems are used to transmit multiple waveforms at different frequencies, then frequency coverage is improved, but device complexity increases
Solution Approach 1:
The patent implements a single sonar system capable of transmitting broadband waveforms that cover multiple frequency ranges (20-1000 kHz), replacing the need for multiple separate sonar systems. The system can dynamically adjust its operating frequency and waveform type (chirp, noise, click, or click train) to perform various classification tasks across different frequency bands, achieving multi-functionality within one unified platform.
2Measurement precision
If matched filtering techniques are used for signal processing, then signal detection is improved, but loss of information increases due to frequency constraints
Solution Approach 1:
The patent extracts and removes the matched filtering step from the signal processing chain, allowing the raw broadband echo signals to be preserved in their original form. By eliminating matched filters that would constrain the frequency content, the system maintains access to the complete frequency spectrum of the returned signals, enabling post-processing analysis across all frequencies without loss of information.
Solution Approach 2:
The system performs preliminary broadband signal acquisition and storage before any frequency-specific analysis. By capturing the entire broadband spectrum upfront and storing the raw data, the system enables flexible post-processing where frequencies of interest can be selected and analyzed after data collection, rather than being constrained by pre-defined frequency filters during acquisition.
3Measurement precision
If narrow beamwidth is used to focus on discrete targets, then measurement precision is improved, but area of coverage decreases
Solution Approach 1:
The patent employs periodic scanning of narrow beams across different spatial positions and angles. By systematically moving the focused narrow beam through multiple positions over time, the system achieves both high measurement precision at each point and comprehensive area coverage through the sequence of measurements, effectively trading time for spatial coverage.
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
Provides high frequency resolution and flexibility in choosing frequencies of interest post-processing, allowing for detailed sea floor and water column characterization without prior knowledge of specific frequencies.
Implementation Method 1
a transceiver for synthesizing a transmitter message including a frequency modulated (FM), noise-like, click, or click train message with a frequency between 20 and 1000 kHz and with a bandwidth of 100 kHz or more; and, the message for exciting the projector array such that a 180 degree or smaller swath of a waterbody bottom is ensonified by the message, and a message echo from ensonified scattering centers is returned to the hydrophone array
Implementation Method 2
a transceiver for synthesizing a transmitter message including a frequency modulated (FM), noise-like, click, or click train message with a frequency between 20 and 1000 kHz and with a bandwidth of 100 kHz or more; and, the message for exciting the projector array such that a 180 degree or smaller swath of a waterbody bottom is ensonified by the message, and a message echo from ensonified scattering centers is returned to the hydrophone array
Data Source
AI summary
A sonar survey system and method excites reflectors using a broadband message that excites all frequencies within the band providing for selection and evaluation of frequencies of interest after the survey is completed.