Mobile Device Orientation to Vehicle Reference Frame
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Solution Overview
Problem
Existing systems for tracking and evaluating driving behavior lack accuracy in collecting and interpreting data related to driver behavior during driving events.
Innovation Solution
The use of a mobile device to orient itself relative to a vehicle's reference frame, utilizing sensors such as accelerometers and magnetometers to determine orientation and transform data into a vehicle-centric frame, allowing for the identification of driver behavior and exit detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mobile device data is collected in the mobile device's own reference frame, then data collection is simple and device complexity is low, but measurement precision and reliability of driving behavior tracking deteriorate due to mismatch with vehicle reference frame
Solution Approach 1:
The patent introduces an intermediary computational process (reference frame transformation using quaternions) that mediates between the mobile device's reference frame and the vehicle's reference frame. This transformation acts as a bridge, converting accelerometer and magnetometer data from the mobile device coordinate system into the vehicle coordinate system, thereby resolving the mismatch without requiring physical reorientation of the device.
Solution Approach 2:
The patent changes the parameter representation of spatial orientation by using quaternions instead of traditional Euler angles. This parameter transformation enables more efficient and numerically stable reference frame transformations, improving measurement precision while managing computational complexity through a different mathematical representation of the same physical orientation data.
2Measurement precision
If external devices are integrated with vehicles to track driving behavior, then data accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent makes the mobile device universal by enabling it to perform multiple functions: it serves as both a general-purpose consumer device and a specialized driving behavior tracking instrument. By utilizing the mobile device's existing sensors (accelerometer, magnetometer) and applying reference frame transformations, the system achieves vehicle-specific measurement capabilities without requiring dedicated hardware integration, thereby reducing device complexity while maintaining data accuracy.
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 enables more accurate and comprehensive tracking of driving behavior, including distracted driving and exit detection, by aligning mobile device data with the vehicle's reference frame, thereby improving data accuracy and applicability.
Implementation Method 1
determining an orientation of a gravity vector and aligning a first axis of the mobile device with respect to the gravity vector
Implementation Method 2
determining an orientation of a magnetic direction and aligning a second axis of the mobile device with respect to the magnetic direction
Data Source
AI summary
Techniques for identifying mobile device use by a driver of a vehicle during a driving event are provided. In an example, motion data collected by one or more sensors of a mobile device during a driving event are obtained. Using the motion data, the motion data is reoriented to the reference frame of the vehicle. From the reoriented motion data, it is determined that the mobile device moved toward a driver's side of the vehicle and a front screen of the mobile device faced the driver's side of the vehicle during the driving event. Based on the movement and orientation of the mobile device toward the driver's side, a use of the mobile device by the driver is identified.