In accordance with this invention, generally stated, a navigation system for a vehicle is provided with {HEAD ~ terrain correlation} embodied in {TAIL ~ a construction} which is independent of vehicle altitude and which permits curvilinear vehicle course paths 
In accordance with this invention , generally stated , a navigation system for a vehicle is provided with { HEAD ~ terrain correlation } embodied in { TAIL ~ a construction } which is independent of vehicle altitude and which permits curvilinear vehicle course paths
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH