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