Fence Pulse Warning System for False Alarm Reduction
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Solution Overview
Problem
Existing electronic intrusion detection systems along fences experience a high rate of false alarms due to environmental factors like wind, rain, and animals, making it difficult for security personnel to pinpoint actual intrusion attempts.
Innovation Solution
An electronic warning system with a pulser, transmitter, receiver, and sensors along a fence, where a processor determines the location of phenomena by measuring the time taken for pulses to return after being absorbed by an impedance-matched resistor, and sets a threshold for repeated pulses within a preset time to differentiate between false and true alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors detect and respond to vibrations or changes in volume along the fence line, then intrusion detection capability is improved, but the rate of false alarms increases due to environmental factors like wind, rain, and animals
Solution Approach 1:
The fence line is divided into multiple segments with sensors spaced at specific intervals (e.g., every 3-5 meters). Each sensor monitors a specific segment, and the central control unit processes signals from individual segments. This segmentation allows the system to identify localized intrusion events and distinguish them from widespread environmental disturbances, reducing false alarms while maintaining detection precision.
Solution Approach 2:
The system dynamically adjusts its detection parameters and alarm thresholds based on environmental conditions and historical data. The central control unit analyzes the characteristics of detected signals (frequency, amplitude, duration) and adapts sensitivity levels to differentiate between legitimate intrusions and environmental noise such as wind, rain, or animal movements, thereby reducing false alarm rates while preserving detection accuracy.
2Measurement precision
If sensors are spaced closely together along the fence line, then detection accuracy is improved, but the complexity and cost of the system increases
Solution Approach 1:
The system implements varying sensor spacing strategies based on local security requirements and environmental conditions. High-risk areas or zones with frequent false alarms may have denser sensor placement, while low-risk areas use wider spacing. This localized optimization achieves adequate detection accuracy without uniformly increasing system complexity across the entire fence line.
Solution Approach 2:
The system adjusts detection parameters such as alarm thresholds, signal filtering criteria, and sensor sensitivity levels to compensate for variations in sensor spacing. By optimizing these parameters, the system maintains high detection accuracy even with moderate sensor spacing, avoiding the need for dense sensor placement and the associated increase in system complexity.
3Area of stationary object
If the system monitors the entire fence line continuously, then security coverage is improved, but the burden on security personnel increases due to high false alarm rates
Solution Approach 1:
The central control unit implements feedback mechanisms that analyze signals from all sensors, identify patterns, and provide intelligent filtering. When environmental conditions suggest high false alarm probability (e.g., windy weather), the system automatically adjusts sensitivity or suppresses non-critical alarms. This feedback loop maintains comprehensive security coverage while significantly reducing the number of false alarms that reach security personnel, thereby easing their operational burden.
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 system significantly reduces false alarms by accurately locating intrusions and distinguishing between environmental influences and unauthorized activity, enhancing the effectiveness of security personnel responses.
Implementation Method 1
an impedance having a resistance substantially identical to the line characteristic resistance and connected at the end of said line, for absorbing said pulses when said pulses are received thereby at the end of said line so that said pulses do not return to said receiver
Implementation Method 2
Satisfactory detection results were obtained with the usage of sensors detecting and responding to vibrations or to changes in volume, operating in the ultrasonic or infrared frequency ranges.
Implementation Method 3
Satisfactory detection results were obtained with the usage of sensors detecting and responding to vibrations or to changes in volume, operating in the ultrasonic or infrared frequency ranges.
Implementation Method 4
Satisfactory detection results were obtained with the usage of sensors detecting and responding to vibrations or to changes in volume, operating in the ultrasonic or infrared frequency ranges.
Implementation Method 5
a transmitter for transmitting pulses through said line
Implementation Method 6
said processor including means for determining the time taken by a said pulse to return to said receiver in response to the actuation of a said sensor so as to determine the location of the actuated sensor
Data Source
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AI summary
The invention provides an electronic warning system, including an electrical line of a fence extending along a protected area, a pulser, a transmitter for transmitting pulses through the line, a receiver for receiving the pulses after being transmitted along at least a portion of the line, an impedance having a resistance substantially identical to the line characteristic resistance and connected at the end of the line, for absorbing the pulses when the pulses are received thereby at the end of the line so that the pulses do not return to said receiver, a plurality of sensors disposed at spaced-apart locations along the line and actuated responsive to phenomenon occurring in the vicinity thereof, for, when actuated, causing the pulses to return to the receiver, and a processor for operating the transmitter and receiver and for actuating a warning signal upon the detection, by at least one of the sensors, of the phenomenon. The processor has means for determining the time taken by the pulse to return to the receiver in response to the actuation of the sensor so as to determine the location of the actuated sensor, thus determining the location at which the phenomenon occurred, characterized in that the processor further includes means for presetting and determining the number of pulses received during a preset period of time from receipt of a first pulse, resulting from an occurrence and repeated occurrences of the phenomenon at the same location, and for actuating a warning signal beyond the number of pulses. A method for distinguishing between false alarms and true unauthorized activity along a fence or at the vicinity thereof, is also provided.