Speed Sensor Cross-Correlation Peak Detection
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Solution Overview
Problem
Marine sonar speed sensors face challenges in distinguishing reflections from particles from spurious signals and background noise, leading to unreliable speed measurements, especially at higher or lower speeds, and are computation-intensive, particularly when there are too many or too few particles in the water.
Innovation Solution
The method involves generating signals related to the intensity of reflections from particles, using a particle detection scheme that includes filtering and quantization to determine relative speed, and can involve multiple receivers to measure speeds in various dimensions, with corrections applied based on known relationships with cross-correlation-based measurements or reference devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-correlation techniques are used to determine speed from reflection patterns, then speed measurement capability is provided, but computational intensity increases significantly
Solution Approach 1:
The patent extracts only the essential features needed for speed measurement by using peak detection in the cross-correlation function rather than analyzing the entire reflection pattern. This selective extraction of critical information (time delay between peaks) dramatically reduces computational requirements while maintaining speed measurement capability
Solution Approach 2:
The system performs preliminary signal processing by transmitting acoustic pulses and recording reflections before the actual speed calculation. The cross-correlation function is pre-computed from the recorded signals, allowing speed to be determined simply by identifying peak positions rather than performing complex analysis during operation
2Reliability
If pattern recognition is used to distinguish particle reflections from background, then measurement reliability improves, but computational complexity increases
Solution Approach 1:
The patent applies local quality by focusing analysis only on specific regions of the cross-correlation function where particle reflections are expected to appear. By examining only the relevant time delay ranges and using threshold-based peak detection, the system achieves reliable particle identification without processing the entire signal spectrum
Solution Approach 2:
The system uses a simplified approach that may detect some false peaks but compensates through multiple measurements and statistical analysis. Rather than attempting to perfectly distinguish every particle reflection, the system performs partial analysis on multiple pulses and uses the aggregate results to determine reliable speed measurements
3Measurement precision
If sonar signals are transmitted to detect particles, then speed sensing capability is provided, but spurious signals and electronic noise interfere with measurements
Solution Approach 1:
The patent introduces the cross-correlation function as an intermediary between the raw sonar signals and the speed measurement. This intermediary process enhances the signal-to-noise ratio by correlating reflections from multiple pulses, allowing true particle signals to emerge from the background noise and spurious reflections
Solution Approach 2:
The system uses feedback by comparing the received signals with expected reflection patterns and adjusting the analysis parameters accordingly. The cross-correlation technique provides feedback on the consistency of detected peaks across multiple pulses, allowing the system to distinguish genuine particle reflections from random noise
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 enhances the reliability and range of speed measurements by effectively distinguishing particle signals from noise and background, improving accuracy across different speed conditions and particle densities, and reduces computational intensity.
Implementation Method 1
a first receiver for generating a first plurality of signals, each of the first plurality of signals being related to an intensity of reflections received from a first monitored region containing one or more particles
Implementation Method 2
A time between the particle's entering and leaving the detection span of the transducer is measured to devise a speed
Data Source
AI summary
Embodiments relate to a speed sensor and a speed sensing method for measuring relative speeds of receivers with respect to particles in a fluid by detecting individual particles. A receiver generates a plurality of signals related to reflections from particles in a region being monitored. A sampling circuit samples the signals, and a processing device processes the signals according to a particle detection scheme to determine speed. Concomitant use of the same receivers allows depth measurement.