Asset Tracking Geofence Boundary Validation
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Solution Overview
Problem
Existing wireless asset tracking systems experience high rates of false positive geofence boundary crossing alerts due to inaccuracies in GPS position fixes, especially in obstructed or indoor environments, leading to costly reactions and decreased system reliability.
Innovation Solution
The system employs tracking devices that communicate site identities from fixed wireless networks, using a default list of site identities to filter out false positive alerts by comparing current site identities and calculating differential angles between position fixes to determine valid excursions from geofence boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS position fixes are used to determine asset location, then position tracking capability is provided, but false positive geofence boundary crossing alerts increase due to position fix inaccuracies
Solution Approach 1:
The patent introduces cell site identity as an intermediary reference point to validate GPS position fixes. Instead of directly trusting GPS coordinates, the system uses the cell site identity (a more reliable wireless network identifier) as a mediator to confirm whether an asset has truly crossed a geofence boundary. This intermediary helps distinguish between actual boundary crossings and false positives caused by GPS inaccuracies.
Solution Approach 2:
The system implements feedback by continuously monitoring cell site identities and comparing them against previous positions. When a GPS position suggests a boundary crossing, the system feedback-checks whether the cell site identity has actually changed. This feedback mechanism allows the system to validate position fix accuracy and filter out false positive alerts before generating boundary crossing notifications.
2Reliability
If GPS tracking is continuously monitored to detect boundary crossings, then boundary excursion detection capability is provided, but network and processor resources are consumed
Solution Approach 1:
The patent applies partial action by selectively processing position data only when necessary. Instead of continuously analyzing every GPS position fix, the system performs detailed boundary crossing analysis only when the cell site identity changes or when a position fix suggests a potential boundary crossing. This partial processing approach maintains reliable boundary detection while significantly reducing network and processor resource consumption during normal operation.
3Reliability
If cell site identity changes are used to filter false positives, then false positive alert rate decreases, but device complexity increases due to additional filtering logic
Solution Approach 1:
The patent extracts the cell site identity information from the wireless network signals and separates it from the GPS position processing logic. By extracting this independent reference data, the system creates a simple comparison mechanism: does the cell site identity match the expected value for the current geofence zone? This extraction approach reduces filtering logic complexity while maintaining false positive reduction effectiveness.
Data Source
AI summary
Systems and methods for tracking assets from central stations using tracking devices enabled to receive GPS coordinates or site identities broadcast from transmitters at fixed locations within a wireless network. Plural position fixes are taken over time and forwarded to the central station. The position fixes are compared to establish a likelihood that apparent excursions from a predetermined boundary area are valid or not, prior to generating an alert signal that the asset has moved from the boundary area.