APPLICATION OF REAL-TIME FLIGHT SIMULATION FOR DESIGN OF A HELICOPTER OBSTACLE AVOIDANCE SYSTEM

An analysis of the current Northrop helicopter obstacle avoidance system (OASYS) prototype was conducted to determine system effectiveness during simulated aircraft level flight accelerations in the airspeed range from 0 to 100 knots, and at acceleration rates of from 0 to 2.9 meters per second squared. The fixed, forward mounted OASYS prototype with a 25 x 50 degree field of view features an 860 nanometer wavelength LADAR. This is similar to conventional radar except that it provides much better detection of thin targets such as wires, thus giving excellent protection against the wire-strike threat. Computer simulation flights were conducted using flight parameter data at the Army Aero-flightdynamics Directorate Crew Research and Development Facility's (CSRDF) advanced concepts flight simulator. A multiple-program computer simulation was used to model the helicopter and sensor dynamics over a tactical data base of numerous obstacles consisting of trees, wires, and poles. The resulting window of safety (WOS) displays were analyzed by comparing each acceleration maneuver with a control maneuver in which the sensor was horizon stabilized. Based on these simulations, a mathematical model was developed for those maneuvers for which the OASYS prototype operated effectively. The limits of this analytical flight envelope were then verified using a series of computer simulations of maneuvers conducted over a standardized obstacle base.