Improvement of terrain following flight adaptive angle method under small field of view conditions

The causes of two wavy tracks were examined in light of the phenomenon of aircraft moving forward in a wavy mode during terrain following flight with the adaptive angle method under the condition of a small field of view. An improved adaptive angle method formula was also proposed when terrain information is lost. A new suppression function was designed and the command gain was derived for the improved formula which verified its consistency with altitude control. The guidance instruction can be given continuously by combining the information before terrain loss with the real-time altitude in the stage of no terrain information. Through the avoidance of frequent changes in flight path angle and normal overload, the method is confirmed to be effective in addressing the wavy track issue in visual simulation experiments with various real terrain data. This allows the aircraft to fly over the peak at the expected safe height and significantly improves the terrain following effectiveness.