A system for determining orientation of an apparatus, the system comprising: one or more accelerometers rigidly mounted to the apparatus; one or more magnetometers rigidly mounted to the apparatus; and a controller configured to (i) receive signals from the one or more accelerometers and the one or more magnetometers and (ii) determine tilt, roll, and yaw angles of the apparatus, wherein the controller is configured to: determine the tilt and roll angles of the apparatus based on the signals from the one or more accelerometers; and determine the yaw angle of the apparatus based on (a) the determined tilt and roll angles and (b) the signals from the one or more magnetometers, CHARACTERIZED IN THAT: at least one pair of accelerometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction; and / or at least one pair of magnetometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction. one or more accelerometers rigidly mounted to the apparatus; one or more magnetometers rigidly mounted to the apparatus; and a controller configured to (i) receive signals from the one or more accelerometers and the one or more magnetometers and (ii) determine tilt, roll, and yaw angles of the apparatus, wherein the controller is configured to: determine the tilt and roll angles of the apparatus based on the signals from the one or more accelerometers; and determine the yaw angle of the apparatus based on (a) the determined tilt and roll angles and (b) the signals from the one or more magnetometers, CHARACTERIZED IN THAT: at least one pair of accelerometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction; and / or at least one pair of magnetometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction. determine the tilt and roll angles of the apparatus based on the signals from the one or more accelerometers; and determine the yaw angle of the apparatus based on (a) the determined tilt and roll angles and (b) the signals from the one or more magnetometers, CHARACTERIZED IN THAT: at least one pair of accelerometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction; and / or at least one pair of magnetometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction. at least one pair of accelerometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction; and / or at least one pair of magnetometers is arranged as antipodes with their X axes pointing in opposite directions, their Y axes pointing in opposite directions, and their Z axes pointing in the same direction.