Vehicle Speedometer Calibration Using GPS and Speed-Range Tolerances
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Solution Overview
Problem
Existing vehicle speedometers often display an indicated speed that is higher than the actual speed, leading to discrepancies that can be exacerbated by tire tuning, causing consumer dissatisfaction and legal non-compliance.
Innovation Solution
An indicated speed tolerance apparatus that dynamically corrects the displayed speed using GPS information and wheel speed data to minimize errors within legal tolerance ranges, adjusting for vehicle and road conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed tolerance value is used for indicated speed calculation, then the device complexity is reduced, but the measurement precision deteriorates due to large errors between indicated speed and actual speed
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed tolerance value to a dynamically adjustable tolerance value that changes based on vehicle speed sections. The processor automatically selects appropriate tolerance values from a pre-stored set corresponding to different speed ranges, enabling the system to adapt to varying operating conditions without requiring complex real-time calculations or additional hardware.
Solution Approach 2:
The patent implements parameter changes by modifying the tolerance value parameter based on the vehicle speed section. Different tolerance values are pre-stored for different speed sections, and the processor selects the appropriate parameter value according to the current speed range, thereby improving measurement precision across various operating conditions while maintaining system simplicity.
2Measurement precision
If dynamic correction using GPS information is implemented, then the measurement precision is improved, but the use of energy increases due to continuous GPS data processing
Solution Approach 1:
The patent applies preliminary action by pre-storing multiple tolerance values corresponding to different vehicle speed sections before the vehicle operation begins. This allows the system to quickly select the appropriate tolerance value based on the current speed section without requiring complex real-time calculations or continuous GPS data processing, thereby reducing energy consumption while maintaining improved measurement precision.
3Adaptability or versatility
If tolerance range is varied based on vehicle condition and road type, then the adaptability is improved, but the device complexity increases due to multiple sensing requirements
Solution Approach 1:
The patent applies universality by designing a speed correction system that can handle multiple vehicle conditions and road types using a unified approach. The processor varies the tolerance range based on vehicle speed sections that encompass different operating conditions, eliminating the need for separate sensing systems for each condition while maintaining high adaptability across diverse scenarios.
Data Source
AI summary
An embodiment apparatus for correcting an indicated speed tolerance includes a global positioning system (GPS) receiver, a processor, a memory coupled to the processor and storing instructions that, when executed by the processor, cause the processor to calculate an indicated speed by using a tolerance value for each vehicle speed section of a plurality of vehicle speed sections based on a wheel speed, and to correct an error between the indicated speed and a vehicle speed by using an actual speed of a vehicle based on GPS information received from the GPS receiver, and a display device configured to display the indicated speed.