1. A method of determining vehicle acceleration information with a mobile device disposed in a vehicle, the method comprising: operating at least one sensor of the mobile device to obtain a plurality of movement measurements; calculating, based on input from the at least one sensor of the mobile device, a plurality of gravity vectors, each of the plurality of gravity vectors being associated with at least two movement measurements of the plurality of movement measurements; generating, with a vector analyzer of the mobile device, a gravity angle difference and a gravity magnitude difference associated with at least one movement measurement in which the mobile device was moving in the vehicle of the at least two movement measurements, and determining that the gravity angle difference is above a first threshold and that the gravity magnitude difference is above a second threshold; removing the at least one movement measurement from the plurality of movement measurements using the plurality of gravity vectors to provide a set of remaining movement measurements of the mobile device; and determining an acceleration measurement for the vehicle using the remaining movement measurements of the mobile device.