A detector is configured to determine the position of the tracking device so that the determined position of the tracking device associated with the second linkage member determines the position of {HEAD ~ the first linkage member} which is physically coupled to {TAIL ~ the trackable object} 
is physically coupled to
A detector is configured to determine the position of the tracking device so that the determined position of the tracking device associated with the second linkage member determines the position of { HEAD ~ the first linkage member } which is physically coupled to { TAIL ~ the trackable object }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL