A portable position tracking apparatus including: a power supply; a position sensor that receives signals and uses the signals to determine an absolute position of the apparatus; a trigger sensor; and, an electronic processing device in communication with the position and trigger sensor (121, 122) that: monitors the power supply to determine an available power; determines a trigger in response to a signal from the trigger sensor; in response to detection of the trigger, uses the available power to control operation of the position sensor to thereby selectively determine the absolute position; and, stores an indication of a position of the apparatus in a store at least partially in accordance the absolute position, characterized in that the trigger includes a change in movement of the apparatus, and wherein the electronic processing device: determining the trigger in response to the signal from the trigger sensor includes: (a) detecting movement of the apparatus using a motion sensor as trigger sensor; selectively determining the absolute position includes: (a) estimating trip duration using historical position tracking data; and, (b) selecting a sampling strategy using the estimated trip duration and the available power to allow selective sampling of the absolute position in response to the trigger and based upon the available power of the apparatus. a power supply; a position sensor that receives signals and uses the signals to determine an absolute position of the apparatus; a trigger sensor; and, an electronic processing device in communication with the position and trigger sensor (121, 122) that: monitors the power supply to determine an available power; determines a trigger in response to a signal from the trigger sensor; in response to detection of the trigger, uses the available power to control operation of the position sensor to thereby selectively determine the absolute position; and, stores an indication of a position of the apparatus in a store at least partially in accordance the absolute position, monitors the power supply to determine an available power; determines a trigger in response to a signal from the trigger sensor; in response to detection of the trigger, uses the available power to control operation of the position sensor to thereby selectively determine the absolute position; and, stores an indication of a position of the apparatus in a store at least partially in accordance the absolute position, characterized in that the trigger includes a change in movement of the apparatus, and wherein the electronic processing device: determining the trigger in response to the signal from the trigger sensor includes: (a) detecting movement of the apparatus using a motion sensor as trigger sensor; selectively determining the absolute position includes: (a) estimating trip duration using historical position tracking data; and, (b) selecting a sampling strategy using the estimated trip duration and the available power to allow selective sampling of the absolute position in response to the trigger and based upon the available power of the apparatus. determining the trigger in response to the signal from the trigger sensor includes: (a) detecting movement of the apparatus using a motion sensor as trigger sensor; (a) detecting movement of the apparatus using a motion sensor as trigger sensor; selectively determining the absolute position includes: (a) estimating trip duration using historical position tracking data; and, (b) selecting a sampling strategy using the estimated trip duration and the available power to allow selective sampling of the absolute position in response to the trigger and based upon the available power of the apparatus. (a) estimating trip duration using historical position tracking data; and, (b) selecting a sampling strategy using the estimated trip duration and the available power to allow selective sampling of the absolute position in response to the trigger and based upon the available power of the apparatus.