Mid-air, near mid-air, and on-ground collisions are main causes of accident in general aviation. The aim of ODESSA (Obstruction DEtection Sensor for Surveillance on Aircraft) project is to provide both airplanes and helicopters, piloted on board or remotely, with a small, light, and low-cost sensor (compared to the present ones) to prevent collisions while maneuvering close to the terrain (i.e. take off and landing phases) or on-ground (i.e. taxi phase). This objective will be achieved by exploiting the experience gained in the automotive market, where low-cost and reliable radars combined with video cameras are mounted on motor vehicles for the early detection of the obstacles. By equipping the avionic system with this kind of sensors, the collision avoiding capabilities will be dramatically enhanced with a quite small investment. It will result in increased safety during landing approach and on-ground handling or taxi phases, regardless of the airport infrastructure. The final ambition of ODESSA is to improve the TAWS or TCAS capabilities, already provided for civil aviation platforms, contributing to the development of the Modular Surveillance System (MSS) in the Clean Sky 2 Systems ITD WP1.3