Abstract: A system and method for determining the optimal path for an aircraft to fly from a first position to a second position so that the aircraft heading at the second position is within preselected minimum and maximum heading limits. A two-dimensional reference grid is constructed so that the first position is in the center cell of the first rank of the grid and the second position is adjacent to the center cell of the last rank thereof. Dynamic programming techniques are used to determine the possible flight paths between the first and second positions and to select the path of minimum cost as the optimal path. The possible flight paths are constructed by identifying the possible connections between the last rank and the second postion and then between each pair of adjacent ranks, working backward from the last rank to the first position, which is located in the first rank. A possible connection is deemed to exist when the aircraft can fly from one point to a target point (e.g.

Abstract: An apparatus and method for adjusting set clearance altitude of an aircraft to control the aircraft to fly along a predetermined path relative to the terrain below. A terrain following radar system and a stored terrain elevation data base are used to determine the respective positions and elevations of selected portions of the terrain downrange from the aircraft. This information is used along with pre-stored information relating to the ability of a ground threat to detect the aircraft and the roughness of the terrain to compute three different altitudes. The first altitude (Ia) represents the maximum height at which the aircraft can fly without being detected by the ground threat. The second altitude (Da) represents the maximum desired altitude of the aircraft at any time during a flight. The third altitude (Ra) represents the minimum altitude at which the aircraft is allowed to fly.