Normalized Speed Profiles for Navigation Accuracy
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Solution Overview
Problem
Existing navigation devices rely on inaccurate speed data, which can lead to sub-optimal route planning and incorrect Estimated Times of Arrival (ETA), due to variations in traffic density and speed profiles that are not adequately accounted for in current map data.
Innovation Solution
A navigation device that uses normalized speed profiles, measured and scaled using free flow speed, to improve data accuracy and compression, allowing for more accurate routing instructions by mirroring real traffic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional speed data from map vendors is used, then route planning can be performed, but the accuracy of speed data and ETA calculations deteriorates due to inadequate representation of traffic density variations
Solution Approach 1:
The patent segments the speed profile into multiple discrete speed values corresponding to different time periods (e.g., morning rush hour, midday, evening rush hour, night) rather than using a single average speed. This segmentation allows the system to select the appropriate speed value based on the current time, thereby accurately representing traffic density variations throughout the day and improving both speed data accuracy and route planning reliability
Solution Approach 2:
The patent introduces dynamic speed profiles that change based on time of day, day of week, and other temporal factors. Instead of static speed data, the system maintains multiple speed values that are dynamically selected based on current conditions, allowing the route planning to adapt to varying traffic patterns and thereby improving reliability while maintaining measurement precision
2Measurement precision
If multiple speed profiles for different time periods are stored, then routing accuracy improves, but memory requirements increase
Solution Approach 1:
The patent stores multiple speed profiles for different time periods but only loads and processes the relevant profile based on the current time. This partial action approach allows the system to maintain comprehensive speed data for accuracy while only utilizing the necessary subset at any given moment, thereby improving routing accuracy without proportionally increasing active memory requirements
Solution Approach 2:
The patent changes the parameter representation by using normalized speed profiles where speeds are expressed relative to a base speed rather than absolute values. This parameter transformation allows for more compact storage while maintaining the ability to accurately represent different traffic conditions, thus improving routing accuracy while reducing memory storage requirements
Data Source
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Figure 2
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AI summary
A navigation device and a method of operating a navigation device are disclosed. The navigation has a stored map comprising: a plurality of navigable segments representing segments of a navigable route in the area covered by the map with each segment having speed data associated therewith; and a plurality of normalised speed profiles, each speed profile representing the variation in traffic speed in relation to free flow speed along a segment over a predetermined period of time. The speed data associated with each segment comprises an identifier providing a reference to one of the normalised speed profiles and a free flow speed for the segment. The device has a route planning algorithm that uses the map stored in the memory to plan a route from a start location to a destination location, wherein the estimated speed of travel along each segment is determined based on the time of traversal within the predetermined period of time and by using the free flow speed for the segment to scale the speed profile referenced by the indicator.