Geo-fence False Alarm Minimization via Vote of Two Validation
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Solution Overview
Problem
Existing GPS-based location systems often result in inaccurate position fixes near the ground, leading to a high probability of false notifications when monitoring geographically defined areas, as they lack effective means to minimize false positives and maintain accuracy in geo-fencing applications.
Innovation Solution
A method and system that utilize a GPS receiver with an internal antenna subsystem, a wireless data transceiver, and application software incorporating a false alarm minimization algorithm. This algorithm considers position fix error ellipse characteristics, geographic zone area polygon characteristics, and position fix retries to enhance the accuracy of determining device entry or exit from a pre-provisioned zone, employing a 'vote of two' mechanism to confirm boundary crossings and adjusting geo-fence factors for improved precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS position fixes are used for geo-fence boundary crossing detection, then location tracking capability is provided, but false positive notifications occur frequently due to inaccurate position fixes near the ground
Solution Approach 1:
The system performs preliminary validation of position fixes by checking if they meet minimum accuracy thresholds (horizontal and vertical dilution of precision) before using them for boundary crossing detection. This preliminary filtering prevents inaccurate fixes from triggering false alarms.
Solution Approach 2:
The system implements a feedback mechanism where boundary crossing detections are validated through multiple position fixes and confidence level assessments. The false alarm minimization algorithm continuously monitors position accuracy and adjusts detection sensitivity based on the reliability of received position data.
2Measurement precision
If geo-fence area is reduced to increase monitoring precision, then detection accuracy improves, but false alarms increase due to GPS error ellipse
Solution Approach 1:
The system dynamically adjusts geo-fence parameters including the effective radius (reducing it from the full error ellipse major axis to a smaller value based on confidence levels), confidence thresholds, and detection sensitivity. These parameter changes allow precise monitoring of small zones while compensating for GPS errors through statistical confidence assessment.
Solution Approach 2:
The system performs preliminary confidence level assessment and multiple position fix validation before declaring a boundary crossing. This preliminary verification ensures that only statistically significant crossings trigger notifications, reducing false alarms in small geo-fence areas.
3Reliability
If multiple position fixes and confidence validation are implemented to reduce false alarms, then false positive rate decreases, but system complexity and processing time increase
Solution Approach 1:
The system uses configurable parameters such as minimum position fix count, confidence level thresholds, and validation intervals to control the complexity of the validation process. These parameters allow tuning of the system to achieve desired reliability while managing computational complexity.
Solution Approach 2:
The system performs validation to the minimum necessary extent rather than exhaustive checking. It uses a pragmatic approach where a sufficient number of position fixes are validated to achieve acceptable confidence levels without overly complex processing, balancing reliability with system simplicity.
Data Source
AI summary
A method and apparatus is disclosed for a wireless device locator system and determining whether a device has entered or exited a two dimensional geographic zone area and alerting the device user when the device has entered or exited the zone. The method and apparatus may further minimize the probability of false zone entry and exit zone area alerts to wireless tracking device users.