US 2006/0214843 A1Published application

A Ground-Based or Airborne Scanning Radiometer with Precision All-Weather Calibration.

OwnerMarian Klein, Albin Gasiewskiinventors

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Abstract

This invention describes a design of a structure that allows microwave radiometers to be calibrated under all conditions of weather and atmospheric fallout. The thermal emission standards radiating surfaces are kept free of hydrometeors (liquid water, ice, or snow), dust, dirt, soot, oils, ash, or other organic and inorganic matter during extended operation. Meanwhile, the radiometer are allowed an unobstructed view of scene under observation, for example, the entire sky from horizon to horizon as well as most of the ground underneath. The effects of any attenuating or scattering matter that accumulates on the elements of the beam forming system are compensated for since the thermal emission standards are viewed in front of the first element of beam forming system (e.g. lens, radome, protective window). In this manner the same amount of dirt, hydrometeors, etc. on radiometer first element of beam forming system as present during the viewing of the scene under observation will be present during calibration. The thermal emission standards' radiating surfaces are kept clean and free of attenuating or scattering matter, thus the precision, stability, and radiation characteristics of thermal reference are maintained.

Claims13

Dependent claims

A passive radiometer system for operation within an atmosphere that provides unobstructed viewing of the environment's radiation field along with calibration of the system's radiometers under nearly all conditions of weather and atmospheric fallout, comprising:

means for forming and pointing the radiometer beams in one or more viewing modes, including any of the following:
an elevation scan over a range of angles up to a full circle;
an azimuth scan over a range of angles up to a full circle;
a two-dimensional scan using a combination of elevation and azimuth angles;
a fixed viewing angle or set of angles;
a stepwise scan over a discrete set of azimuth, elevation, or azimuth and elevation angles;
and
means for calibrating each radiometer accounting for the attenuating and scattering effects of all reflecting, refracting, diffracting, and protective elements of each radiometer's beam forming and pointing system by periodically training the radiometer beams on one or more thermal reference standards while simultaneously measuring the radiometer output;
and
means for maintaining the precision of said thermal reference standards by protection from external environmental influences;
and
means for rapidly moving (a) the radiometer assembly consisting of said radiometers, beam forming, and beam pointing apparatus and (b) the thermal reference standards relative to each other so as to provide an unobstructed view of the environment by the radiometers over any predetermined viewing mode.

9 more elements

Dependencies are inferred from the claim text.