1. A method for determining a crab angle of a portable electronic device, wherein the crab angle is an angle by which the device direction of travel differs from the device orientation, and wherein the device is provided with a vector accelerometer, the method comprising: determining an acceleration vector using the vector accelerometer; rotating the acceleration vector so that one component is parallel to the vertical; and computing the device crab angle by finding the direction in the horizontal plane having maximal energy associated therewith.