Peripheral scan hazard detection system

Power lines represent a major hazard to low flying helicopters. In the past, systems developed to warn pilots of power lines and other obstructions in the vehicle´s projected flight path have been heavy, expensive, subject to high false alarm rates and have operated too slowly to be suitable for highly agile aircraft. This paper addresses a design that suffers from none of these problems. The design is based on the fact that for a target to be in the aircraft´s flight path it must first pass through the perimeter of a “cone of protection”. Using simple cw laser diodes, we scan along the surface of this cone rather than the entire volume of space in front of the aircraft. This permits the use of lower laser power and much faster scan frame times-on the order of 2.5 msec. These faster frame times are more consistent with aircraft dynamics and permit noise filtering