In order to operate outside military ranges, UAVs need a means of achieving "see and avoid" at least equivalent to that achieved in manned aircraft. In this project, we propose to take low-cost visual image processing devices currently being developed by Mercedes-Benz as collision avoidance devices for the automotive market and adapt them for use in UAVs. We will use the analysis tools and encounter logic developed for the Traffic Alert and Collision Avoidance System (TCAS) to create an "Optical TCAS" that operates passively and can be installed at extremely low cost. We will use unique panospheric mirrors to achieve 360 degree coverage around the UAV without the need for complex and expansive scanning systems. Development and testing of this system will be facilitated through the use of Aurora's "Chiron" optionally piloted aircraft, which will allow continuous testing aboard an actual UAV operating in the National Airspace System. In Phase I, we will collect data on component performance and perform system trade studies. In Phase II, we will fabricate a prototype system, conduct ground tests, install the system Aurora's optionally piloted aircraft, the "Chiron," and fly actual test encounters to measure in-field effectiveness.