Integration of Active and Passive Sensors for Obstacle Avoidance

This paper studies the automatic obstacle-avoidance guidance problem under the operational constraints imposed by the rotorcraft nap-of-the-earth (NOE) environment. The topic is discussed under two different circumstances. The first one assumes that a full range map is available, irrespective of the type of sensor being used. Two approaches are proposed to extend a two-dimensional obstacle-avoidance concept presented in a previous report. The second part of the paper deals with the situation where only a sparse range map is available from a passive sensor. An integrated approach to augment the passive sensor with an active one is discussed, along with the problem of data fusion and how it is affected by the characteristics of NOE flight.