GPS and Geomagnetic Sensor Fusion for Accurate Street Corner Detection
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Solution Overview
Problem
Existing GPS-based running condition detection systems inaccurately measure distance due to positional data variations, especially at street corners, leading to discrepancies between prescribed and actual distances in marathon courses.
Innovation Solution
A running condition detection device incorporating a GPS receiving unit, geomagnetic sensor, direction determination unit, and a control unit that compares current and reference data to accurately detect street corners, using both GPS and geomagnetic data to correct distance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS positional data is used to measure running distance, then distance measurement is enabled, but measurement precision deteriorates due to positional data variations and shortcuts at street corners
Solution Approach 1:
The patent combines GPS positional data with geomagnetic sensor data to determine running distance. The geomagnetic sensor detects changes in magnetic field direction at street corners, providing complementary information that corrects GPS measurement errors. This merging of multiple sensing modalities resolves the contradiction by using the strengths of each sensor to compensate for the weaknesses of the other.
Solution Approach 2:
The system continuously compares GPS-derived position with geomagnetic sensor-derived orientation and provides feedback to correct distance measurements. When the geomagnetic sensor detects a street corner (sudden change in magnetic direction), the system adjusts the distance calculation to account for the actual running path, creating a closed-loop correction mechanism that improves measurement precision over time.
2Measurement precision
If GPS positional data is skipped at preset intervals to reduce error, then measurement precision improves, but detection of street corners deteriorates
Solution Approach 1:
The system uses periodic sampling of geomagnetic data at fixed time intervals to detect street corners. This periodic action allows the system to maintain accurate street corner detection without requiring continuous high-frequency GPS updates, thus improving overall measurement precision while maintaining detection capability through the periodic geomagnetic checks.
Solution Approach 2:
The geomagnetic sensor acts as an intermediary that detects street corners independently of GPS sampling frequency. By using the geomagnetic field as an intermediate reference, the system can accurately identify street corners even when GPS data is sparse, allowing preset skipping of GPS positional data while maintaining street corner detection accuracy.
3Measurement precision
If multiple sensors are integrated to improve detection accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The geomagnetic sensor serves multiple functions: it detects street corners, determines running orientation, and provides feedback for distance correction. This multi-functionality reduces the need for additional specialized sensors, thereby improving measurement precision without proportionally increasing device complexity. The same sensor performs multiple detection tasks that would otherwise require separate components.
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 system provides precise detection of street corners, reducing measurement errors and ensuring accurate distance tracking along marathon courses by integrating GPS and geomagnetic data for improved positional accuracy.
Implementation Method 1
a GPS receiving unit which receives a GPS signal and outputs a current position
Implementation Method 2
a geomagnetic sensor which detects geomagnetism
Data Source
AI summary
A running condition detection device includesa GPS receiving unit configured to receive a GPS signal and output a current position,a geomagnetic sensor configured to detect geomagnetism,a direction determination unit configured to obtain a current moving direction based on current positional data and last positional data from the GPS receiving unit,a first bend determination unit configured to compare current moving direction data obtained by the direction determination unit and reference direction data to determine passage of a street corner,a second bend determination unit configured to compare geomagnetic data detected by the geomagnetic sensor and reference geomagnetic data to determine passage of a street corner, anda determination prohibition unit which prohibits the first and second bend determination units from determining passage of a street corner during a given period of time when passage of a street corner is determined by one of the first bend determination unit and the second bend determination unit.