<title>Obstacle detection and warning for helicopter flight using infrared and millimeter wave</title>

Abstract

Helicopters often strike against thin obstacles such as power lines. To prevent such collisions,we are developing an obstacle detection and warning system for helicopters. An Infrared (IR)camera,a color camera and a Millimeter Wave (MMW)radar are employed as its sensor components.This paper describes the performance of the system. 94GHz FMCW radar has been developed for this system. The Vivaldi antenna has been fabricated for the radar. The range accuracy of the radar is tested by the measurements. The radiation pattern of the Vivaldi antenna is measured in the anechoic chamber. The validity of the IR camera to detect obstacles is evaluated by the flight measurements.IR images, collected by the measurements are employed to analyze the effect of the background brightness and to develop new rendering techniques to enhance obstacles. The results show that the accuracy of the FMCW radar is within 5%. The Vivaldi antenna has good characteristics but its transition circuit deforms the total antenna pattern. It is shown that IR camera greatly increases the possibility to detect obstacles even in poor visibility. The normal distribution in the IR spectrum proves to be enough to analyze the image and to derive the obstacle information. The IR image rendered by the pseudo color method is effective to enhance obstacles.