Seismic Intrusion Detection with Electrical Resistivity Tomography
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Solution Overview
Problem
Existing systems for perimeter intrusion detection and subsurface anomaly detection lack the ability to continuously and automatically monitor both surface and subsurface conditions, failing to adequately identify and track subsurface intrusions, surface activities, and their directional information.
Innovation Solution
A network of master controllers and node arrays equipped with electrical resistivity tomography (ERT) systems and various sensors, which communicate with a system server, client device, and administrator device to continuously monitor and analyze surface and subsurface conditions, detecting trigger events and determining their path, velocity, and acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional visual monitoring systems are used, then surface intrusion can be recognized, but subsurface intrusion remains unidentified and constant monitoring requires excessive expense and labor
Solution Approach 1:
The patent replaces visual monitoring systems with seismic sensor networks that detect ground vibrations and electrical resistivity changes. This substitution enables automatic detection of both surface and subsurface intrusions without requiring constant human visual monitoring, thereby reducing labor costs while improving detection precision across multiple dimensions (surface and subsurface).
Solution Approach 2:
The patent transitions from two-dimensional surface monitoring to three-dimensional subsurface monitoring by deploying sensors at multiple depths and using electrical resistivity tomography. This dimensional expansion allows detection of tunneling activities and subsurface movements that traditional surface-level visual systems cannot detect, comprehensively addressing intrusion detection needs.
2Measurement precision
If subsurface sensors are installed to detect subsurface activity, then subsurface intrusion can be detected, but surface activity monitoring is insufficient and directional information is lost
Solution Approach 1:
The patent divides the monitoring system into multiple sensor nodes deployed at different locations and depths. Each node independently monitors local conditions, and the network collectively provides comprehensive coverage of both surface and subsurface activities. This segmentation enables precise localization of intrusions and reconstruction of directional information through spatial analysis of sensor data.
Solution Approach 2:
The system continuously analyzes seismic signals and electrical resistivity changes to provide real-time feedback about intrusion events. By processing signals from multiple sensors and comparing them against threshold values, the system can determine direction of travel, velocity, and acceleration of intrusions, preventing information loss while maintaining high detection precision.
3Productivity
If automated sensor systems are deployed for perimeter monitoring, then labor requirements are reduced, but the system cannot accurately identify the cause or direction of pressure changes
Solution Approach 1:
The patent employs multi-functional sensor nodes that simultaneously measure seismic vibrations, electrical resistivity changes, and ground pressure variations. This multi-functionality enables a single automated system to detect intrusions, characterize event types (tunneling, surface movement, animal activity), and determine directional information, thereby maintaining high productivity while preventing information loss.
Solution Approach 2:
The system uses composite sensing approaches that combine multiple physical measurement modalities (seismic, electrical, pressure) to create a comprehensive detection capability. By analyzing the composite signal from different sensor types, the system can accurately identify the cause of pressure changes and extract directional information, overcoming the limitations of single-sensor automated systems.
4Measurement precision
If manual ERT survey systems are used, then subsurface imaging is possible, but continuous automatic monitoring cannot be achieved
Solution Approach 1:
The patent implements self-service monitoring through autonomous sensor nodes that automatically perform ERT surveys at scheduled intervals without human intervention. The system self-calibrates, self-diagnoses, and continuously monitors subsurface conditions, enabling both high measurement precision for subsurface imaging and continuous automatic operation for real-time intrusion detection.
Solution Approach 2:
The system performs preliminary ERT surveys to establish baseline subsurface conditions before intrusion events occur. By having pre-established baseline data, the system can rapidly detect and characterize changes in subsurface resistivity patterns, maintaining both imaging precision and continuous monitoring capability through proactive measurement strategies.
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 system provides continuous and automatic monitoring of both surface and subsurface conditions, enabling timely detection of subsurface anomalies and surface intrusions, and reporting important event details such as direction of travel, velocity, and acceleration.
Implementation Method 1
electrical resistivity tomography (ERT) systems for detecting subsurface anomalies
Implementation Method 2
subsurface sensors, such as piezoelectric transducers. Referring then to FIG. 1, a series of subsurface sensors 22 are installed around perimeter 12 of a secure facility. Subsurface sensors 22 detect pressure changes in the soil caused by surface movement
Implementation Method 3
sensors 105 are fixed on the ground surface by stakes 150. Processor 130 correlates signals received from geophone 110 and acoustic transducer 120
Implementation Method 4
U.S. Pat. No. 8,659,424 to Krumhansl, et al. discloses a system for detecting subsurface perimeter intrusion using sets of seismic sensors
Data Source
AI summary
The invention disclosed provides a network of master controller and node arrays which all communicate with a system server, a client device and an administrator device. Each of the master controller and node arrays is equipped with an ERT system, and various seismic sensors to monitor a geographic perimeter for surface and sub-surface trigger events. Upon detection of a trigger event, each of the master controller and node arrays executes a sensor monitoring routine to determine the approximate path of travel, velocity, acceleration of the trigger event. The master controller and node arrays further conduct an ERT survey to determine the presence of anomalies which may indicate sub-surface activity related to the trigger event.