Compass View Correction Using Map Data Offsets
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Solution Overview
Problem
In magnetically challenged environments, mobile device compass applications often provide inaccurate navigation due to compass heading biases, leading to a poor user experience.
Innovation Solution
The system corrects the compass view by using map data to compensate for sensor inaccuracies, determining compass offset data, and presenting a corrected compass view that aligns with vector map data, such as street centerlines, thereby improving navigation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compass sensor data is used directly for navigation display, then the compass view can be provided quickly and simply, but the directional accuracy deteriorates in magnetically challenged environments
Solution Approach 1:
The patent introduces map data as an intermediary element to mediate between the unreliable compass sensor and the navigation display. The system uses the known geometric structure of map features (street centerlines, paths) as a reference framework to correct compass deviations. By comparing the raw compass bearing against the expected bearing derived from map data, the system calculates and applies a correction offset, effectively using map data as a mediator to resolve the inconsistency between sensor output and actual direction.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the discrepancy between compass-indicated direction and map-derived expected direction. The calculated offset angle is fed back into the compass rendering process to adjust the directional indicator. This closed-loop feedback ensures that compass inaccuracies are dynamically corrected based on the difference between sensor output and map reference, improving directional accuracy without requiring hardware changes.
2Measurement precision
If map data is used to correct compass offset, then navigation accuracy is improved, but the processing complexity and computational requirements increase
Solution Approach 1:
The patent applies partial correction by focusing only on the essential map features needed for correction - specifically street centerlines or path geometries - rather than processing the entire map dataset. The system calculates the expected bearing using only the relevant segment of map data that corresponds to the user's current location and direction of travel. This selective processing reduces computational overhead while maintaining navigation accuracy, as full map processing would be excessive for the correction task.
3Reliability
If the compass offset is continuously corrected using map data, then the directional indicator accuracy is maintained, but the computational load increases
Solution Approach 1:
The patent implements periodic correction by updating the compass offset calculation at specific intervals or when certain conditions are met (e.g., when the user reaches a new street segment or when significant time has elapsed). Rather than continuously recalculating the offset from map data, the system maintains the correction between updates, reducing processor activity and energy consumption. This periodic approach maintains compass view reliability while avoiding the excessive computational load of continuous recalculation.
Data Source
AI summary
Systems, methods, devices and computer-readable storage mediums are disclosed for correcting a compass view using map data. In an implementation, a method comprises: receiving, by one or more sensors of a mobile device, sensor data; determining, by a processor of the mobile device, compass offset data for a compass view based on the sensor data and map data; determining, by the processor, a corrected compass view based on the compass offset data; and presenting, by the processor, the corrected compass view.