{HEAD ~ a second positioning system} arranged in {TAIL ~ the second vehicle} for determining the position of the second vehicle; and 
arranged in
{ HEAD ~ a second positioning system } arranged in { TAIL ~ the second vehicle } for determining the position of the second vehicle ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH