Intermittent GPS Control for Wristwatch Power Savings
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Solution Overview
Problem
Conventional GPS receivers for wristwatch-type devices consume excessive energy, making them unsuitable for accurate tracking of running courses while minimizing power consumption.
Innovation Solution
A GPS receiving apparatus with a GPS receiving unit, motion sensor, and controlling program that intermittently activates the GPS based on proximity to predetermined course positions, using motion data to conserve energy and enhance position accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS receiver operates continuously to detect position accurately, then position detection accuracy is improved, but power consumption increases
Solution Approach 1:
The GPS receiver operates intermittently rather than continuously, activating only when the user approaches a predetermined course position within a specified distance. This periodic operation based on proximity triggers reduces power consumption while maintaining accurate position detection at critical points along the course.
Solution Approach 2:
The system pre-stores course position data and predetermined distance thresholds in the storage unit. By having this information prepared in advance, the GPS receiver can quickly determine when to activate without continuous operation, enabling efficient intermittent measurement that balances accuracy with power savings.
2Use of energy by moving object
If GPS receiver operates intermittently to save energy, then power consumption is reduced, but position detection accuracy deteriorates
Solution Approach 1:
The system uses motion detection feedback from the motion detection unit to determine when the user is moving along the course. This feedback mechanism triggers GPS activation at appropriate moments, ensuring position detection accuracy is maintained during active movement while allowing power savings during stationary periods or when the user is far from course positions.
Solution Approach 2:
The system replaces continuous GPS mechanical operation with a hybrid approach combining motion detection (from motion detection unit) and intermittent GPS activation. This substitution allows the system to use lower-power motion sensing for continuous monitoring while reserving high-precision GPS for critical measurement moments.
3Measurement precision
If GPS receiver operates continuously, then course tracking accuracy is improved, but battery capacity requirement increases
Solution Approach 1:
The GPS receiver operates periodically based on proximity to predetermined course positions rather than continuously. This intermittent operation triggered by distance thresholds significantly reduces total energy consumption, allowing accurate course tracking with a smaller battery capacity suitable for wristwatch-type devices.
Solution Approach 2:
The system changes the operational parameters of the GPS receiver from continuous high-power operation to intermittent low-power operation. By adjusting the activation threshold (predetermined distance) and using motion detection triggers, the system maintains course tracking accuracy while reducing average power consumption to levels compatible with small battery capacities.
Data Source
AI summary
A GPS receiving apparatus includes a GPS receiving unit which detects a position, a course data storing unit which stores course data representing a course, along which plural transit positions are set, a motion sensor which detects motion of a user, a moving-distance obtaining unit which obtains a moving distance of the user based on the detected user's motion, a proximity judging unit which judges based on the obtained moving distance whether the user has come close to a next transit position along the course, a GPS start-up controlling unit which makes the GPS receiving unit start up, when the proximity judging unit determines that the user has come close to the next transit position, and a GPS stop controlling unit, which brings the GPS receiving unit down, when it is determined that the user has passed through the next transit position.