Position Calculation Device Using Traveling Direction Axis Correction
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Solution Overview
Problem
Existing position calculation methods for users, such as those using inertial navigation with sensors, face challenges in accurately determining the position when the user's body orientation changes during walking or running, as the velocity vector's direction varies with respect to the traveling direction, making it difficult to accurately calculate the user's position.
Innovation Solution
A method that sets a traveling direction axis using sensor detection results, corrects it based on changes in user movement, and calculates the position using predetermined constraint conditions, incorporating a Kalman filter to estimate changes in the traveling direction and yaw angle, while limiting movement to directions other than the primary axis to reduce errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inertial navigation arithmetic is performed using velocity vector from sensor measurement, then position calculation can be performed, but position calculation accuracy deteriorates when user body orientation changes during walking or running
Solution Approach 1:
The system dynamically adjusts the coordinate system by detecting changes in the velocity vector direction and rotating the traveling direction axis accordingly. This dynamic adaptation allows the system to maintain accurate position calculation even when the user's body orientation changes during movement, as the coordinate system evolves with the user's motion pattern rather than remaining fixed
Solution Approach 2:
The system uses feedback from the velocity vector measurements to detect changes in traveling direction and continuously corrects the traveling direction axis. By monitoring the velocity vector orientation and applying corrections based on detected directional changes, the system compensates for body orientation variations and maintains positioning accuracy throughout the movement sequence
2Difficulty of detecting and measuring
If sensor is mounted on body portion to detect movement, then movement detection is achieved, but traveling direction axis becomes inaccurate due to periodic body orientation changes
Solution Approach 1:
The system extracts the essential traveling direction information from the velocity vector measurements while separating it from the noisy body orientation changes. By focusing on the velocity vector direction as the primary indicator of traveling direction and ignoring the periodic body orientation variations, the system isolates the useful signal from the distracting motion patterns
Solution Approach 2:
The traveling direction axis serves as an intermediary that mediates between the raw sensor measurements and the final position calculation. This intermediate coordinate system absorbs the effects of body orientation changes and provides a stable reference frame for position calculation, acting as a buffer between the noisy sensor data and the positioning algorithm
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
This approach allows for accurate position calculation of users by correcting the traveling direction axis and reducing errors caused by body orientation changes during walking or running, effectively improving the precision of position determination.
Implementation Method 1
an acceleration sensor and a gyro sensor are included in the sensor, and the estimating includes performing correction by using a Kalman filter in which the change amount in the traveling direction is set as an element of a state vector and a change in a yaw angle based on the detection result of the gyro sensor is set as an element of an observation vector
Data Source
AI summary
A position calculation device includes an acceleration sensor and a gyro sensor to detect a movement of the user which is mounted on the body of the user, an arithmetic processing unit which executes setting a traveling direction axis by using a detection result of the sensor, using a change in a traveling direction of the user and correcting the traveling direction axis, and calculating a position based on the detection result of the sensor by using predetermined constraint condition based on the traveling direction axis.