Pedestrian Traveling Direction Estimation Using Acceleration Vectors
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Solution Overview
Problem
Existing algorithms for estimating a pedestrian's traveling direction using acceleration sensors are inaccurate, particularly due to variations in travel courses and device posture, making it difficult to obtain precise location estimates.
Innovation Solution
An information processing device that includes a processing unit executing determination processing, first and second direction acquisition processing, and second traveling direction estimation processing, using a combination of gravity direction and perpendicular acceleration components to estimate the traveling direction, and employing filter processing and rotational offset acquisition to account for shifts in posture and travel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional algorithms using only acceleration sensor input are used, then the device complexity is low, but the measurement precision of traveling direction deteriorates
Solution Approach 1:
The patent combines multiple acceleration measurements taken at different timings and orientations into a unified traveling direction estimation. By merging the first acceleration (a1) obtained when the device is held in a reference posture with the second acceleration (a2) obtained when the device posture changes, the system achieves more accurate direction estimation without requiring additional sensors, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent performs preliminary acceleration measurement (a1) when the information processing device is held in a predetermined posture before the actual traveling direction estimation. This preliminary action establishes a reference direction that compensates for device posture variations, allowing subsequent measurements (a2) to be accurately interpreted regardless of how the user holds the device, thereby improving measurement precision without increasing hardware complexity.
2Measurement precision
If the algorithm accounts for device posture changes and travel course variations, then the measurement precision improves, but the ease of operation deteriorates
Solution Approach 1:
The system automatically detects and compensates for device posture changes without requiring user input or awareness. The information processing device autonomously performs preliminary acceleration measurement in a predetermined posture, then uses this reference to correct subsequent measurements taken during actual movement, regardless of how the user holds the device. This self-service approach maintains ease of operation while significantly improving measurement precision.
3Reliability
If multiple acceleration measurements are taken at different timings and orientations, then the reliability of traveling direction estimation improves, but the loss of time increases
Solution Approach 1:
The patent employs periodic acceleration measurements at strategically chosen timings: first measuring when the device is held in a predetermined posture (reference measurement), then measuring again when the device is used during actual movement. This periodic sampling approach captures sufficient information for reliable direction estimation without continuous measurement, thereby maintaining high reliability while minimizing time loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables more accurate and robust estimation of traveling directions, even during changes in travel courses and device posture, by calculating a second traveling direction vector that is less dependent on initial reference directions, thus improving location estimation accuracy.
Implementation Method 1
acquiring a first acceleration applied to the information processing device, and acquiring a first direction based on the first acceleration
Implementation Method 2
estimating a current location of a pedestrian based on an input signal of an acceleration sensor
Data Source
AI summary
The information processing device 1 includes an acceleration acquisition unit, a vertical direction estimation unit, and a traveling direction estimation unit. The acceleration acquisition unit acquires acceleration occurring by the movement of the user. The vertical direction estimation unit estimates a first vertical direction based on the acceleration acquired by the acceleration acquisition unit. The traveling direction estimation unit estimates a first traveling direction (first traveling direction vector) corresponding to the first vertical direction (first vertical direction vector) estimated by the vertical direction estimation unit. The traveling direction estimation unit estimates a second traveling direction (second traveling direction vector) by shifting the first traveling direction based on the vertical direction as reference and the vertical direction (second vertical direction vector) estimated after the reference vertical direction by the vertical direction estimation unit.