Proposed is a dual-mode sensor for use aboard unmanned aircraft for safe operation in the NAS that: 1. Incorporates high resolution Millimeter Wave radar with high resolution Electro-Optical sensor. 2. Achieves complete real time, full time spherical coverage around the UAS platform by employing two hemispherical dual mode sensors, one directed forward and one directed to the rear.[which exceeds the detection range and field-of-regard (FOR) for all nearby air platforms in FAA Regulation 7610.4 and other requirements from DOD/FAA documents]. 3. Utilizes multiple coherent transceivers. 4. Meets SWaP and cost requirements for most UASs, including price (less than $3000 in quantity), size (less than 1 cubic feet), weight (less than 2 lb) and power (less than 10W). 5. Leverages as needed the Automatic Dependent Surveillance Broadcast (ADS-B), which will be implemented by the FAA in the NAS. 6. Considers aircraft that operate without ADS-B. 7. Performs multiple functions; including autonomous detection, tracking, predicting of future track and specification of collision avoiding maneuvers. 8. Is self-contained, with sensor capability combined with on-board computing and flight control system, yet can be operated with sense and avoid interoperability.