Mobile Time Zone Detection Using Hilbert Curve Indexing
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Solution Overview
Problem
Many mobile devices lack the ability to accurately determine their time zone, relying on unreliable Network Identity & Time Zone (NITZ) data, which can be unavailable or incorrect, especially near borders and in regions with complex daylight saving time rules.
Innovation Solution
A time zone index file is generated based on a world map segmented into cells using a space-filling curve, allowing mobile devices to determine their location and update time zones efficiently without network connectivity, using GPS or other location sources, and triggering updates based on device movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Network Identity & Time Zone (NITZ) data is used to determine time zone, then time zone determination can be performed, but the reliability is poor and data may be unavailable or incorrect in many locations
Solution Approach 1:
The patent segments the world map into a grid of cells, with each cell assigned to a specific time zone. This segmentation allows the device to determine time zone by dividing the geographic space into manageable units, improving reliability by using a structured spatial approach rather than relying on potentially unreliable NITZ data.
Solution Approach 2:
The patent introduces an intermediary mechanism - the space-filling curve index structure - that maps geographic coordinates to time zone information. This intermediary enables reliable time zone determination by transforming the complex problem of geographic-to-timezone mapping into a systematic lookup process based on spatial coordinates.
2Measurement precision
If continuous location monitoring is performed to detect time zone changes, then accurate time zone updates can be achieved, but battery consumption increases
Solution Approach 1:
The patent implements periodic action by monitoring device movement at intervals and only triggering time zone re-determination when movement thresholds are exceeded. This approach maintains measurement precision for detecting time zone changes while reducing battery consumption by avoiding continuous monitoring and unnecessary calculations.
Solution Approach 2:
The system uses the device's own movement data and location information to autonomously determine when time zone updates are needed. By leveraging existing sensor data and implementing smart threshold-based triggering, the system achieves accurate detection without requiring energy-intensive continuous monitoring.
3Measurement precision
If a detailed world map with many polygons is used to represent time zones, then time zone accuracy is improved, but the index file size and processing complexity increase
Solution Approach 1:
The patent applies dimensionality change by using a space-filling curve to transform two-dimensional geographic coordinates into a one-dimensional index space. This allows detailed time zone boundary representation to be maintained while simplifying the data structure and reducing processing complexity through efficient linear indexing.
Solution Approach 2:
The patent changes the parameter representation by transforming geographic coordinates into space-filling curve indices. This parameter transformation enables accurate time zone boundary detection while optimizing storage efficiency and reducing the computational complexity of the index file structure.
Data Source
AI summary
Methods, systems, apparatuses, and computer program products are provided for enabling devices to determine the time zone in which they are located. A mobile device may receive location information from one or more sources. Based thereon, the current location of the mobile device may be determined in terms of latitude and longitude. The indication of the current location may be converted to an index value according to a Hilbert curve (or other space-filling curve), and the index value applied to a time zone index file to determine the local time zone. A time zone setting of the mobile device may be updated accordingly. Furthermore, “geofencing” may be used by the mobile device to detect movement towards and through a time zone boundary, leading to a new time zone determination being initiated.