A method and apparatus for determining {HEAD ~ the relative positions} of a first object and {TAIL ~ a second object}  
of
A method and apparatus for determining { HEAD ~ the relative positions } of a first object and { TAIL ~ a second object }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH