Speed Sensor Particle Detection Noise Filtering
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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
A method and system that utilize a particle detection scheme to filter out electronic noise and background signals, using ultrasonic receivers to generate and process signals related to reflection intensities from monitored regions, allowing for reliable speed measurements by quantizing signals and counting detected particles, and optionally measuring displacement and depth with additional receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-correlation techniques are used to determine speed from reflected signals, then speed measurement capability is achieved, but computational complexity increases significantly
Solution Approach 1:
The patent extracts only the essential information needed for speed measurement by detecting particle presence/absence and using simple counting methods, rather than performing full cross-correlation analysis on the entire reflected signal waveform. This extraction approach maintains speed measurement capability while dramatically reducing computational requirements.
Solution Approach 2:
The patent uses simple, computationally inexpensive particle detection and counting methods that can be rapidly executed, replacing the computationally intensive cross-correlation technique. Each pulse detection is a simple, fast operation that can be performed repeatedly without accumulating computational burden.
2Measurement precision
If traditional sonar signal processing is used, then speed data can be obtained, but reliability decreases due to noise and spurious signals
Solution Approach 1:
The patent converts the harmful effect of noise and spurious signals into a benefit by using threshold-based particle detection. Instead of trying to filter out noise through complex processing, the method detects particles based on whether reflected signal intensity exceeds a threshold, effectively ignoring noise below the threshold while reliably detecting actual particles.
Solution Approach 2:
The patent changes the detection parameter from analyzing continuous signal waveforms to detecting discrete particle events based on threshold-exceeded signal intensity. This parameter change from analog waveform analysis to digital event detection improves reliability by making the measurement less sensitive to noise and spurious signals.
3Measurement precision
If cross-correlation methods are employed, then speed measurement is possible, but the system becomes computation-intensive
Solution Approach 1:
The patent segments the continuous signal processing task into discrete particle detection events for each transmitted pulse. Instead of processing the entire signal continuously through cross-correlation, the system divides the task into independent pulse-by-pulse particle detections and counts, significantly improving processing efficiency.
Solution Approach 2:
The patent replaces the mechanical/computationally intensive cross-correlation processing system with a simpler detection and counting system. The complex signal processing mechanism is substituted with straightforward threshold comparison and particle counting, dramatically improving processing efficiency while maintaining speed measurement capability.
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 solution enhances the reliability and range of speed measurements by effectively distinguishing particle signals from noise and background, improving accuracy across varying speed conditions and particle densities, while reducing computational intensity.
Implementation Method 1
A transducer sends a transmitted signal and receives a first return signal at a first time and a second return signal at a second time
Implementation Method 2
A specific example from the marine industry is a sonar speed sensor that is designed with two transmitter-receivers. Sonar signals can be transmitted from acoustic transmitter-receivers, reflected from objects or particles in the water
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.