A hardware in the loop facility for testing multisensor sense and avoid systems

The Italian Aerospace Research Centre and the Department of Aerospace Engineering at University of Naples have been involved in a project for the development of an obstacle detection and tracking suite for autonomous collision avoidance of unmanned aerial systems. In this framework, a flight prototype of an autonomous obstacle detect sense and avoid system has been designed and realized. It is installed onboard a very light aircraft named FLARE. The system is based on multiple-sensor data integration and it includes several components, such as a Ka-band pulsed radar, four electro optical sensors and two processing units. A hierarchical sensor configuration has been chosen in which the radar is the main sensor while EO cameras are the auxiliary ones to increase accuracy and data rate. In order to maximize the outcome of flight tests, an indoor facility for hardware-in-the-loop tests has been developed. The indoor facility includes processing units dedicated to simulate aircraft and intruder dynamics that are provided as input to sensors. The radar is replaced by a simulator, while the real visible camera unit is used. Flight images are displayed on a LCD screen. The facility permits to test multiple critical flight configurations and different sensors combinations. Moreover, the availability of a well assessed simulator allows the research team to support several activities such as: i) tuning of the data fusion techniques (i.e. tracking based on Kalman filtering); ii) system performance validation for a wide range of scenarios; iii) evaluation of alternative architectures that are difficult to be reproduced during flights. Some results of hardware-in-the-loop tracking tests based on flight data are briefly summarized and expected flight performance of the electro-optical system as auxiliary sensor is discussed.