Portable Navigation Device Event-Based Logging
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Solution Overview
Problem
Portable navigation devices (PNDs) face limitations in logging and tracking large amounts of position and time data due to limited storage and processing power, making it impractical to log data frequently or format it usefully, especially for business mileage records and compliance logging.
Innovation Solution
A method is implemented to store position and time-specific information only when specific events occur, such as navigation mode events like route calculation or free-driving mode events like device activation or road deviations, with the option to compress logs and categorize data by usage (personal or business), enabling efficient logging and tracking functions within PNDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position and time data are logged frequently to improve tracking accuracy, then measurement precision is improved, but storage capacity is exceeded and device complexity increases
Solution Approach 1:
The patent extracts only the essential and relevant position and time data points for logging, rather than continuously logging all data. This selective extraction approach maintains tracking accuracy for important events while significantly reducing the overall data volume stored in the limited memory of the PND.
Solution Approach 2:
The system changes the logging parameters dynamically based on navigation state. Different logging intervals and triggers are applied depending on whether the device is in navigation mode or free-driving mode, optimizing the balance between tracking precision and storage utilization.
2Loss of information
If all position and time data are stored to improve logging completeness, then loss of information is reduced, but storage capacity is exceeded
Solution Approach 1:
The system pre-defines specific trigger events (route calculation completion, destination arrival, mode transitions) that determine when data should be logged. This preliminary identification of important moments ensures that critical information is captured without needing to store all intermediate data points.
Solution Approach 2:
The logging function is segmented into different modes (navigation mode and free-driving mode) with distinct trigger events for each mode. This segmentation allows the system to log information selectively based on the current operational context, maintaining completeness for relevant events while managing storage constraints.
3Productivity
If continuous logging is implemented to improve data availability, then productivity is improved, but use of energy increases due to constant processing
Solution Approach 1:
Instead of continuous logging, the system implements periodic logging triggered by specific events. Data is logged at discrete intervals corresponding to important navigation events rather than continuously, significantly reducing the processing energy required while maintaining data availability when needed.
Solution Approach 2:
The logging system automatically determines when to log data based on predefined trigger events without requiring constant user input or complex continuous processing. The system serves itself by monitoring its own state and logging only when relevant conditions are met, optimizing energy efficiency.
Data Source
AI summary
A method of providing a logging function in a portable navigation device and a portable device adapted to provide such a function are described. The method includes the step of storing location information relating to current position and time-specific information relating to a current position in a non-volatile memory of the device to create a log. The storage of such information only occurs when one of a specified set of events occurs, the set of events being specific to either a navigation mode or a free-driving mode of operation of the device.