{TAIL ~ The navigation computer} 10 is adapted to receive update vehicle position from {HEAD ~ a terrain comparison processor} 11, shown in dash lines in FIG 5, and shown in more detail in FIG 6 
{ TAIL ~ The navigation computer } 10 is adapted to receive update vehicle position from { HEAD ~ a terrain comparison processor } 11 , shown in dash lines in FIG 5 , and shown in more detail in FIG 6
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH