Inference of vehicular trajectory characteristics with personal mobile devices
AssigneeCambridge Mobile Telematics Inc.
InventorsLewis D. Girod, Hari Balakrishnan, Samuel Ross Madden
Life of this patent
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Abstract
Accurate longitudinal acceleration, lateral acceleration (perpendicular to the principal direction of motion, and velocity, is inferred by processing raw data from a commodity three-axis accelerometer that may be oriented arbitrarily in a moving vehicle (or carried by a moving user), and whose orientation and position may change arbitrarily during the motion. The approach is applicable to a range of applications, including insurance telematics, driver behavior and risk assessment, and road surface quality assessment.
Claims31
A method comprising inferring vehicular trajectory characteristics, said inferring comprising:
- acquiring using a machine-implemented processor data representing a sequence of acceleration-related measurements of a device, the device being in an unknown and changeable orientation relative to the frame of reference of a vehicle in which the device is traveling;
- forming using a machine-implemented processor a plurality of time segments of the acceleration-related data, wherein the orientation of the device relative to the vehicle when acquiring the data differs between at least some of the time segments;
- for each time segment of a plurality of time segments, using a machine-implemented processor,
- determining data characterizing an orientation of the device relative to a frame of reference of the vehicle during that time segment,
- forming motion-related data in the frame of reference of the vehicle during the time segment, and
- determining data characterizing trajectory characteristics of the vehicle in the time segment;
- and
- storing data characterizing trajectory characteristic of the vehicle determined from the data characterizing the trajectory characteristics in multiple of the time segments.
(canceled)
The method of claim 30 wherein determining a time interval in which the vehicle is stationary uses a threshold picked from statistics of the acceleration-related measurements.
Software stored on a non-transitory machine-readable medium comprising instructions for causing a processor to:
- acquire data representing a sequence of acceleration-related measurements of a device traveling in a vehicle;
- form a plurality of time segments of the acceleration-related data, such that the orientation of the device relative to the vehicle when acquiring the data differs between at least some of the formed time segments;
- for each of a plurality of the time segments,
- determine data characterizing an orientation of the device relative to a frame of reference of the vehicle,
- form motion-related data in the frame of reference of the vehicle during the time segment, and
- determine data characterizing trajectory characteristics of the vehicle in the time segment;
- and
- store data characterizing trajectory characteristic of the vehicle determined from the data characterizing the trajectory characteristics in multiple of the time segments.
Dependencies are inferred from the claim text.