Hierarchical Grid Spatial Indexing for Mobile Location Tracking
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Solution Overview
Problem
Current location determination systems, such as GPS, provide insufficient information about a mobile device's location within specific geographical regions, as they only offer coordinates without context, making it difficult to determine if a device is within a particular region like a store or commercial district.
Innovation Solution
A computationally efficient method and system using a hierarchical grid system to determine if a mobile device is within a predetermined geographical boundary by converting location coordinates into cell identifiers, allowing for efficient searching within a set of cell identifiers representing regions, thereby improving computational efficiency and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Ray Casting is used to determine whether a point is within a polygon, then location determination accuracy is improved, but computational complexity increases significantly
Solution Approach 1:
The patent divides the geographical space into a hierarchical grid system with multiple levels of resolution. Each grid cell is pre-assigned to regions, allowing the system to segment the complex problem of point-in-polygon testing into simpler grid-based lookups. This segmentation reduces computational complexity while maintaining location determination accuracy.
Solution Approach 2:
The patent performs preliminary actions by pre-computing and storing the assignment of grid cells to regions before runtime. During actual location queries, the system only needs to perform simple grid cell identification and lookup operations, rather than performing complex geometric calculations in real-time. This preliminary preparation significantly reduces computational complexity during operation.
2Loss of information
If GPS coordinates are used to track mobile device location, then location tracking is enabled, but the information provided is insufficient for determining presence within specific regions
Solution Approach 1:
The patent introduces grid cell identifiers as an intermediary between raw GPS coordinates and region determination. Instead of directly using coordinates to determine region presence, the system first converts coordinates to grid cell identifiers, which then serve as a bridge to efficiently query region information. This intermediary layer enriches the location information while maintaining tracking efficiency.
Solution Approach 2:
The patent adds a hierarchical grid dimension to the traditional coordinate-based location system. By mapping GPS coordinates to grid cells and then to regions, the system creates an additional dimensional layer that preserves location information while enabling efficient region determination. This dimensional transformation allows the system to work with discrete grid identifiers rather than continuous coordinates.
Data Source
AI summary
Systems and methods including mobile devices determining their location using a location determination system, such as a global positioning system. A database stores the identifiers of cells representative of predefined regions in a hierarchical grid system. The location coordinates as function of time are converted to visitation patterns of the mobile devices to the predefined regions, based on converting the coordinates to cell identifiers and searching the database to find matches between the cell identifiers representing the regions and the cell identifiers representing the mobile device locations. For example, mobile devices having similar visitation patterns can be identified and divided into two groups; and information relevant to a region is transmitted to one of the group but not another. The visitation patterns of the two group after the transmission is identified and compared to measure a difference.