MICROWAVE RADIOMETER AND METHODS FOR SENSING ATMOSPHERIC MOISTURE AND TEMPERATURE

摘要

ABSTRACT OF THE DISCLOSUREA passive, multi-channel microwave radiometer includes anantenna-lens assembly for receiving, and a first waveguidedesigned to provide a common path for propagating, 23.8 GHz and31.4 GHZ atmospheric signals. The 23.8 GHz signal is above thefrequency of relative maximum water vapor absorption and the31.4 GHz signal is near a relative minimum in the water vaporabsorption spectrum. Circuitry is responsive to theatmospheric signals for generating output signals representingthe respective water vapor and liquid content in and thetemperature of the atmosphere. For realtime calibration ablackbody assembly is mounted in the near field of the antenna-lens assembly. The blackbody assembly emits known blackbodymicrowave signals at 23.8 GHz, 31.4 GHz and in the V band. Theradiometer is calibrated during its normal operation by causinga mirror to select the blackbody signals for propagation alongthe common path. The circuitry responds to the blackbodysignals to represent them as first blackbody reference signals.A factory calibrated noise diode assembly adds a known noisymicrowave signal to the first waveguide when a blackbody signalis being processed. The circuitry separately responds to suchcombined blackbody and noisy signals to separately generate asecond blackbody reference signal. These first and secondblackbody reference signals and the known temperature of theblackbody assembly are used to provide realtime calibrationdata that is used in realtime to obtain the output signals inresponse to the atmospheric signals.62207