Trajectory Stay Point Obfuscation for Real-Time Location Privacy
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Solution Overview
Problem
Existing location-based services face challenges in maintaining user anonymity while providing accurate and timely navigation information, as trajectory data can reveal privacy-sensitive information such as origins, destinations, and stay points.
Innovation Solution
An anonymization method that calculates the probability of reaching a stay point within a predetermined distance using geometrical complexity, average speed, and heading differences, and selectively provides or omits data points to location-based service providers to mask stay points as false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If trajectory data is provided to location-based service providers, then service accuracy and timeliness are improved, but user privacy and anonymity are compromised due to reveal of stay points
Solution Approach 1:
The system performs preliminary identification of stay points by analyzing trajectory patterns before data is provided to service providers. By calculating probability metrics and detecting dwelling behavior in advance, the system can mask stay points proactively, preventing privacy leakage while preserving legitimate location service functionality.
Solution Approach 2:
The patent introduces an intermediary anonymization layer between the trajectory data source and location-based service providers. This intermediary component identifies and masks stay points through probability calculations and pattern recognition, allowing service providers to receive processed data that maintains service accuracy without exposing sensitive user privacy information.
2Object-affected harmful factors
If real-time anonymization is implemented to protect user privacy, then privacy protection is improved, but processing complexity and computational overhead increase
Solution Approach 1:
The system applies partial anonymization by focusing computational resources on identifying and masking only stay points rather than anonymizing entire trajectories. By using probability thresholds and dwelling time criteria, the system processes only the necessary portions of trajectory data, reducing overall computational complexity while maintaining effective privacy protection.
Solution Approach 2:
The patent employs parameter-based detection methods, using adjustable thresholds for dwelling time, probability metrics, and spatial proximity to identify stay points. By changing these parameters dynamically based on data characteristics, the system adapts its processing complexity to match the actual privacy risks present in different trajectory datasets.
3Object-affected harmful factors
If stay points are masked to protect privacy, then anonymity is improved, but utility of location-based services deteriorates due to loss of accurate location information
Solution Approach 1:
The system applies selective masking with local quality by preserving the overall trajectory structure and non-sensitive location information while anonymizing only specific stay point segments. This approach maintains the utility of location-based services for route analysis and mobility patterns while protecting sensitive privacy information at specific locations through targeted anonymization.
Solution Approach 2:
The patent implements partial masking of stay points rather than complete anonymization of all location data. By using probability thresholds and dwelling time criteria to selectively identify which points to mask, the system preserves sufficient location information for service utility while anonymizing only the portions that pose privacy risks.
Data Source
AI summary
Embodiments described herein relate to anonymizing of trajectories of mobile devices through the obfuscation of stay points. Methods may include: receiving probe data points of a trajectory in real-time or near real-time from a probe apparatus as it travels along the trajectory; calculating, for each probe data point, a probability of the trajectory reaching a stay point within a predetermined distance; providing sequential sub-sets of probe data points of the trajectory to a location-based service provider in response to the sequential sub-sets of probe data points including probe data points having a probability failing to satisfy a predetermined value; and identifying a potentially last sub-set of probe data points of the sequential sub-sets of probe data points to provide to the location-based service provider in response to identifying a probe data point having a probability of the trajectory reaching a stay point within the predetermined distance satisfying the predetermined value.