The invention can enable the position (i.e., location and/or orientation) of one or more untethered objects to be tracked. One or more transmitters, each of which has a fixed and known positional relationship to a corresponding object, each emit a sequence of position tracking signals. Each transmitter can emit a unique, identifiable position tracking signal so that the transmitter (and the object to which the transmitter is coupled) from which a signal was emitted can be identified, thereby enabling the position of multiple objects to be tracked. Multiple receivers receive the position tracking signals emitted by each transmitter. The receivers record the times at which signals are received. These recorded times can be communicated to a controller, which can determine from the recorded times the location of each object at a time that a position tracking signal was emitted from the corresponding transmitter. If multiple transmitters are coupled to each object, the orientation of the object can be determined in addition to the location. The position tracking signals can advantageously be ultrasonic signals, which require relatively little power, thus enabling the transmitters to be embodied in a physically small device, so that correspondingly small objects can be tracked. The invention can be used to track objects in small and medium-scale tracking spaces and can be adapted to track the position of an object or objects in one, two or three dimensions. An inertial device can be added to the object, in addition to the transmitter, to enhance the tracking of the object's location.