Inertial Navigation Sensor Integrated Motion Analysis for Obstacle Detection

There exists a significant need for automatic obstacle detection systems onboard rotorcraft due to the heavy workload demands that are imposed upon the pilot and crew. The current purpose of obstacle detection systems is not to replace pilot functions; rather the systems must augment the pilot’s ability for the sake of improving mission safety. The benefits of such systems are needed in both military and civilian rotorcraft, although, military usage dictates maximally passive (i.e., covert) operation of the system to minimize the probability of rotorcraft detection. Hence, this paper describes a maximally passive system which relies upon the use of passive imagery and the minimal use of an active component (laser radar). The processing of passive imagery yields range measurements to world points ahead of the rotorcraft, and provides scene analysis functions which are capable of characterizing the terrain. Knowledge of vehicle motion as provided by an onboard Inertial Navigation System (INS) improves the robustness of the techniques of passive ranging which include motion analysis and binocular stereo. In this paper a maximally passive, INS integrated obstacle detection system is described in terms of its processing components, the sensor options which are available, and the requirements which it must satisfy. In addition, high level system implementation issues are discussed.