A 60-GHz Multifrequency Radiometric Sensor for Detecting Clear Air Turbulence in the Troposphere

The temperature profile in a horizontal path forward of an aircraft canbe sensed with a multichannel 5-mm passive radiometric receivingsystem. The characteristic signature of the multichannel radiometricoutput as a function of time would provide a measure of the range tothe region of temperature discontinuity forward of the aircraft.Applicability to clear air turbulence (CAT) detection is predicatedon the assumption that temperature discontinuities, at least in somecases, are associated with regions of such turbulence. It is thereforeconcluded that such a device has potential application as a CATdetector.Preliminary calculations indicate that the presence of a CATregion could be detected approximately 5 to 6 minutes before penetration,on, assuming an aircraft speed of 0i/nm/ h.A description is given of the design and construction of a two-frequency instrument which will be used to support the measurementprogram for determining the correlation between the meteorologicalparameters that are associated with the phenomenon called CAT.A multifrequency multibeam system is also described as the detectorsystem for future supersonic aircraft.