A passive microwave icing avoidance system (MIAS) senses atmospheric
conditions that lead to aircraft icing when the aircraft is flying at an
altitude above the earth's surface. The MIAS includes a 37 GHz receiver
and an 89 GHz receiver coupled to an antenna for sensing two microwave
frequencies at different angles creating six passive microwave beams. The
two receivers output data to a processor that processes the data to
determine the amount of cloud liquid water and generates signals to an
indicator/display to instruct the pilot of an aircraft to divert or
proceed along the flight path.