Abstract: A ground-based data collection, fusion, analysis and communication system and method are provided to effect collision avoidance for unmanned aerial systems. These systems and methods levy minimal demands on the very strict payload size, weight, and power constraints of many unmanned aerial system platforms by providing an off-board, rather than onboard, sensor system and data fusion capability supporting data acquisition and data fusion from a full spectrum of available sensors. These systems and methods include a capability for high-speed all-source data fusion and analysis with an objective of providing advisory information to a remotely-located pilot of an unmanned aerial system in a timely enough manner for the pilot to effect evasive maneuvers in situations to avoid collision between the unmanned aerial system and conflicting aerial traffic.