Mobile Device Step and Direction Tracking via Sensor Fusion
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Solution Overview
Problem
Current mobile devices have limitations in accurately tracking a user's position and movement, particularly in determining the number of steps and direction of travel, which can lead to inefficient use of GPS resources and increased power consumption.
Innovation Solution
A mobile device equipped with an acceleration sensor, direction sensor, and controller that determines the number of steps and direction of travel based on detected acceleration values and geomagnetic data, performing notifications to other devices when a predetermined number of steps in a specific direction is exceeded, thereby reducing the need for frequent GPS usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS is used frequently to track user position, then position tracking accuracy is improved, but power consumption increases
Solution Approach 1:
The system performs preliminary actions by using acceleration sensors and direction sensors to estimate user movement and position changes before activating GPS. The controller continuously monitors acceleration values and direction changes to predict when GPS tracking is needed, thereby avoiding frequent GPS operations and reducing power consumption while maintaining acceptable tracking accuracy.
Solution Approach 2:
The acceleration sensor and direction sensor act as intermediaries between the user's actual movement and the GPS system. These sensors provide intermediate measurements of movement patterns and direction changes, allowing the controller to determine whether GPS tracking is necessary, thus reducing unnecessary GPS operations and lowering power consumption.
2Loss of information
If GPS is used to determine user position, then position information is obtained, but the device complexity and power consumption increase
Solution Approach 1:
The system segments the position tracking function into multiple components: acceleration sensors for detecting movement, direction sensors for detecting orientation changes, and a controller that integrates this data to determine position. This segmentation allows the system to obtain position information through a combination of simpler sensors rather than relying solely on complex GPS operations.
Solution Approach 2:
The system uses the mobile device's own sensors (acceleration and direction sensors) to self-determine position and movement characteristics without continuously externalizing to GPS. The controller processes sensor data to provide position information independently, reducing dependence on complex external GPS systems.
3Use of energy by moving object
If the number of steps and direction are determined using sensors, then power consumption is reduced, but measurement precision may deteriorate
Solution Approach 1:
The system merges the outputs of multiple sensors (acceleration sensor and direction sensor) to improve measurement precision. By combining acceleration data with direction change information, the controller can more accurately determine the number of steps and movement direction, thereby maintaining high measurement precision while reducing power consumption compared to GPS-based approaches.
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 solution enhances the accuracy of tracking user movement without frequent GPS operation, reducing power consumption and improving determination accuracy even in areas with poor signal reception.
Implementation Method 1
an acceleration sensor configured to detect an acceleration value
Implementation Method 2
a direction sensor configured to detect a change of a direction of the mobile device
Data Source
AI summary
A mobile device comprises a communicator configured to communicate with another communication device; an acceleration sensor configured to detect an acceleration value; a direction sensor configured to detect a change of a direction of the mobile device; and at least one controller configured to determine number of steps of a user of the mobile device based on the acceleration value, and a direction of walking of the user based on the change of the direction of the mobile device to perform notification to the other communication device through the communicator when cumulative number of steps of the walking of the user in one of directions exceeds a first value.