Methods and systems for orienting a mobile device to a vehicle's reference frame

A method of providing a quaternion for reference frame transformation, the method comprising:

• (a) initiating a driving event in a vehicle having a vehicle reference frame;
• (b) receiving, from a mobile device having a mobile device reference frame, mobile device data associated with a time stamp;
• (c) determining, from the mobile device data, a first orientation of a gravity vector with respect to a first axis of the mobile device reference frame;
• (d) determining, from the mobile device data, a second orientation of a magnetic direction with respect to a second axis of the mobile device reference frame;
• (e) determining, using Global Positioning System (GPS) data provided by a GPS unit, a direction of travel for the vehicle with respect to the magnetic direction;
• (f) determining a vertical inclination angle for the vehicle, wherein determining the vertical inclination angle for the vehicle comprises determining an altitude change and a distance change using the GPS data provided by the GPS unit;
• (g) computing a quaternion that represents a rotation between the mobile device reference frame and the vehicle reference frame using the first orientation, the second orientation, the direction of travel and the vertical inclination angle for the vehicle;
• (h) determining if the driving event is complete;
• incrementing the time stamp and iterating steps (b), (c), (d), (e), (f), (g), and (h) if the driving event is not complete;
• and
• providing the quaternion for reference frame transformation if the driving event is complete.