Portable Device Sensor Position Change Detection
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Solution Overview
Problem
Pedestrian Dead Reckoning (PDR) methods for tracking user position are prone to error accumulation due to inaccuracies in speed and orientation estimation, which can lead to significant position discrepancies over time, especially when external signals like GPS are not available.
Innovation Solution
A mobile device equipped with motion sensors and processing logic that identifies reference positions and changes in orientation relative to the user, allowing for the determination of orientation changes during rotations, thereby improving the accuracy of PDR calculations by distinguishing between user motion and device orientation changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PDR method is used for position tracking, then the device can operate in any environment with limited resources, but error accumulation occurs over successive iterations leading to increased position error
Solution Approach 1:
The system continuously monitors sensor data and compares detected orientations with reference orientations stored in memory. When deviations are detected, the system adjusts position calculations accordingly, creating a feedback loop that prevents error accumulation and maintains position accuracy over time
Solution Approach 2:
The system pre-stores multiple reference positions and reference orientations in memory before actual navigation begins. These reference data are prepared in advance based on known environmental features, enabling the system to quickly compare and correct position estimates without real-time external signals
2Measurement precision
If motion sensors are used to detect user movement, then the device can track direction and speed, but it becomes difficult to separate user motion from device orientation changes
Solution Approach 1:
The system separates motion analysis into distinct components: device orientation changes are detected and corrected using reference comparisons, while user body motion is analyzed for navigation calculations. This segmentation allows independent processing of each motion type, reducing analytical complexity
Solution Approach 2:
The system introduces reference orientation data as an intermediary element between raw sensor measurements and final position calculations. These references act as a mediator that helps distinguish between device movements and user movements by providing a stable comparison baseline
Data Source
AI summary
The invention relates to a portable device with improved sensor position change detection. It aims at detecting a change of position of a mobile device relative to a user and, based on this change of position, a change of orientation of the mobile device relative to the user. This allows, when the orientation of the mobile device suddenly changes relative to a user, to keep track of this change. This is particularly useful for position tracking techniques such as Pedestrian Dead Recognition (PDR), which rely on an iterative determination of the orientation of a mobile device relative to the user, and may be affected by a sudden and important change of this relative orientation.