ANOE is a NASA project concerned with developing technology to aid helicopter pilots during low-altitude and nap-of-the-earth (NOE) flight through computer and sensor augmentation. The work encompasses pilot-directed guidance, machine vision, active sensors and non-linear inverse control.
Our group has been working on this technology for six years. We are now in the integration and flight demonstration phase. Not all of our technical papers are on-line yet, though some group members have their own papers within their personal pages.
The front cover of the August 1993 issue of the IEEE Control Systems Magazine shows a time-lapse image of our ANOE simulator, helsim, flying a UH-60 Blackhawk. The straight line segments are a portion of the high-level path from a course planner. The guidance system job is to try to follow this nominal trajectory (at a low altitude) until the sensor subsystem detects an obstacle. The guidance system plans an evasive maneuver (a change in velocity vector) based on the latest sensor information.
If the helicopter strays too far from the nominal trajectory while seeking a low-level path, the guidance system would give a bob-up command (fly up and over the offending obstacles). You can see the little yellow helicopter flying over some trees in the middle-left portion of the image.
There are two very difficult asspects of this technology. The first is attaining reliable obstacle information from the sensor subsystems in a timely fashion, and the second is how to make such an obstacle avoidance system acceptable to pilots (i.e., what is the best pilot/system interface). The latter problem is not to be under estimated; if pilots do not trust such a system they would not use it... period.