Miniature radar may put UAVs in the air -- GCN

http://gcn.com/blogs/emerging-tech/2014/06/uav-radar-sense-and-avoid.aspx

The biggest hurdle for unmanned aerial vehicles to clear in order to gain Federal Aviation Administration approval for use in the national airspace is development of systems to prevent them from crashing into each other and, even more important, into manned aircraft.  And the key challenge in developing such a "sense-and-avoid" system has been developing technology that can reliably detect the presence – and the course – of other aircraft and to engineer it into a package small enough and light enough for UAVs.

Researchers at the University of Denver's Unmanned Systems Research Institute may have the answer.  The group has developed a phased-array radar system that weighs only 12 ounces and is small enough to fit in the palm of one's hand.