Mobile Device Orientation Estimation Using GPS and Accelerometer Fusion
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Solution Overview
Problem
Conventional techniques for estimating the orientation of a mobile device with respect to a vehicle are unreliable and inaccurate due to limitations such as reliance on linear acceleration events and directional ambiguity, which restricts the accuracy of orientation estimations and fails to provide reliable information about vehicle impacts and user identity.
Innovation Solution
The system determines the orientation of a mobile device with respect to a vehicle by combining local motion information from inertial sensors with global displacement information from GPS, using a processor to analyze acceleration, gravity, and other data to improve accuracy and reliability, including the use of expanded time windows and quality indicators to filter estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional techniques use only accelerometer data during straight-line travel periods, then device complexity is reduced, but orientation estimation accuracy deteriorates due to directional ambiguity and limited measurement conditions
Solution Approach 1:
The patent combines multiple data sources (accelerometer, GPS, gyroscope) that were previously used separately to merge their advantages: accelerometer provides high-frequency local motion data, GPS provides global displacement information, and gyroscope provides orientation data. This integration resolves directional ambiguity and improves orientation estimation accuracy without requiring complex dedicated hardware
Solution Approach 2:
The system makes mobile device sensors multi-functional by using the same accelerometer and GPS for both traditional navigation functions and for determining vehicle impact characteristics. The sensors serve multiple purposes: device orientation tracking, vehicle crash detection, impact direction determination, and driver behavior analysis, eliminating the need for separate dedicated crash sensors
2Loss of time
If conventional techniques rely on limited straight-line acceleration events, then data processing time is reduced, but reliability of orientation estimation deteriorates due to insufficient data samples
Solution Approach 1:
The system continuously collects and pre-processes motion data during normal vehicle operation before impact events occur. By maintaining an ongoing record of accelerometer and GPS data with proper timestamping and synchronization, the system has ready-to-analyze data when impact occurs, eliminating the need to wait for specific straight-line conditions and enabling immediate reliable analysis
Solution Approach 2:
The patent implements continuous data collection from accelerometers and GPS throughout vehicle operation rather than intermittent sampling during specific conditions. This continuous monitoring ensures that sufficient data samples are always available for reliable orientation estimation and impact analysis, while efficient processing algorithms maintain acceptable processing speeds
3Measurement precision
If the system expands the time window for analysis to improve orientation accuracy, then measurement precision improves, but loss of time increases due to larger data sets requiring processing
Solution Approach 1:
The system pre-organizes continuous sensor data into timestamped segments with proper synchronization between accelerometer, GPS, and gyroscope data during normal operation. This preliminary structuring allows the expanded time window analysis to efficiently access and process only the relevant pre-organized data segments needed for accurate orientation determination, rather than searching through unstructured data
Solution Approach 2:
The patent applies selective processing to the expanded time window data, focusing computational resources on the most informative portions of the data set. By identifying and prioritizing key measurement periods within the expanded window that contain the most orientation information, the system achieves high measurement precision while minimizing unnecessary processing of less informative data
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 significantly enhances the reliability and accuracy of orientation estimation, enabling the determination of impact directions, evasive maneuvers, and user identity, reducing directional ambiguity and improving the accuracy of orientation determination.
Implementation Method 1
estimates of the orientation of a mobile device with respect to a vehicle rely on information from inertial sensors of the device, such as an accelerometer
Implementation Method 2
receive global displacement information regarding the mobile device
Data Source
AI summary
A system for determining an orientation of a mobile device with respect to a vehicle. The system comprises at least one computer processor programmed to: receive local motion information regarding the mobile device; receive global displacement information regarding the mobile device; and based on the local motion information regarding the mobile device and the global displacement information regarding the mobile device, determine the orientation of the mobile device with respect to the vehicle. A method for determining an orientation of a mobile device with respect to a vehicle, and at least one computer-readable storage medium having instructions recorded thereon which, when executed by a computer, cause the computer to perform the method.