Systems and methods for constraining growth in position uncertainty of a mobile device are based on determination that the mobile device is in a pedestrian mode. Determination of the pedestrian mode is based on detection of steps by a pedometer, speed of motion of the mobile device, turn rate determination by a gyroscope, charging condition of the mobile device, availability of satellite signals, etc. Step counts and/or turn rate information are used to ascertain the distance that a pedestrian user may have traversed from a last known position, based on which growth of position uncertainty is controlled.