Seismic Sensor Frequency Analysis for False Alarm Reduction
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Solution Overview
Problem
Conventional seismic sensors incorrectly detect pulse-shaped shocks from man-made vibrations as earthquakes, leading to potential false outputs of cutoff signals for energy supply.
Innovation Solution
The seismic sensor employs an acceleration measurement unit, an acceleration waveform generation unit, a frequency sensing unit using the zero-crossing method, and an earthquake determination unit to accurately differentiate between earthquake and non-earthquake vibrations based on frequency analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seismic sensor uses conventional vibration detection methods, then it can detect strong vibrations, but it mistakenly identifies pulse-shaped shocks from man-made vibrations as earthquakes
Solution Approach 1:
The patent changes the parameter used for earthquake determination from vibration intensity alone to frequency characteristics. By using the zero-crossing method to sense frequency, the system can distinguish between earthquake vibrations (lower frequency) and man-made pulse-shaped shocks (higher frequency), thereby reducing false positives while maintaining reliable earthquake detection
Solution Approach 2:
The patent replaces conventional mechanical vibration threshold detection with a frequency-based detection method using zero-crossing analysis. This substitution allows the system to differentiate between different types of vibrations based on their frequency characteristics rather than just amplitude, eliminating false alarms from man-made sources
2Speed
If the seismic sensor transitions to measurement mode upon detecting acceleration, then it can respond quickly to potential earthquakes, but it increases power consumption and may trigger false alarms
Solution Approach 1:
The patent applies preliminary action by performing frequency sensing using the zero-crossing method immediately when acceleration is detected, before fully transitioning to high-power measurement mode. This allows the system to quickly filter out false positives from man-made vibrations, enabling faster return to power-saving mode when no earthquake is present, thus reducing overall power consumption while maintaining quick response capability
Solution Approach 2:
The patent uses feedback by continuously monitoring frequency characteristics during the measurement process. The zero-crossing method provides real-time frequency information that feeds back to the determination logic, allowing the system to adjust its operation - quickly returning to power-saving mode when frequency analysis indicates non-earthquake vibrations, thereby optimizing the balance between response speed and power consumption
Data Source
AI summary
A seismic sensor 10 comprises an acceleration acquisition unit 21, an acceleration waveform generation unit 22, a frequency sensing unit 24, and an earthquake determination unit 25. The acceleration acquisition unit 21 detects vibration and measures the acceleration of the vibration. The acceleration waveform generation unit 22 generates an acceleration waveform that indicates the relation between the elapsed time and the acceleration measured by the acceleration acquisition unit 21. The frequency sensing unit 24 senses the frequency of the acceleration waveform generated by the acceleration waveform generation unit 22 using a zero-crossing method. The earthquake determination unit 25 determines whether or not there is an earthquake on the basis of the frequency sensed by the frequency sensing unit 24.