Pilot Oriented Aids For Helicopter Automatic Nap-Of-The-Earth Flight

There is currently a high degree of interest in Nap-of-the- Earth (NOE) helicopter flight as is evidenced in the mission requirements for the LHX program. Low altitude flight, particularly at NOE elevations, can be a high stress operating environment in which reaction times are minimal and tolerance for error nonexistent. There are recent advances in technology which can provide significant support to the pilot. A combination of digital map technology and accurate navigational aids such as GPS and inertial reference units can furnish an accurate knowledge of the local terrain and the helicopter position with respect to it. Advances in sensor technology are beginning to afford rapid. detailed and reliable near-field navigational information. Forward Looking Infrared sensors (FLIR), millimeter wave radar (MMW) and CO2 laser radars are being used, in tests, to detect wires. tree limbs, and other hazards as well as for exposing targets and threats. There has also been an evolution of significant real-time software which can aid in navigation in the NOE environment. Two recent developments hold promise for helping to automate NOE navigation. Dyna path a dynamic programming-based set of algorithms developed by TAU Corporation, is currently being evaluated by NASA-Ames in real-time man-in-the-loop simulations as an NOE pilot aid. Dynapath solves for the optimal (light path in the near field (next 30 seconds) environment using digital terrain and on-board sensor data. Another tool, Dynaplan, performs globally optimized flight path determination using digital terrain data, threat information, and helicopter performance parameters. This sof'tware tool is reliable, relatively fast and can be implemented both in planning a mission and can potentially be used on-board, for rapid mission replanning.