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