Calibration method suitable for surface source lunar measurement of ground-based microwave radiometer

Abstract

The invention relates to a calibration method suitable for surface source lunar measurement of a ground-based microwave radiometer, which belongs to the technical field of calibration of a microwave radiometer. The calibration method relies on the microwave radiometer mounted on a satellite, a working wave band of the microwave radiometer is a microwave wave band of 1-1000 GHz, and wave beam widthof an antenna main wave beam 3dB is less than 0.25 degree, and the method includes the following steps: step one. performing calibration on a receiver of the rear end of an antenna; step two. allowing a main beam of the microwave radiometer to be aligned with the moon; step three. observing the moon to obtain observation output; and step four. obtain an absolute brightness temperature curve of the moon according to a time sequence, allowing the transverse axis to represent time, and allowing the longitudinal axis to represent the absolute brightness temperature of the moon. In order to correct the influence of an external antenna and secondary reflection, the method adopts a mode of observing the moon, and performs a certain mathematical process to obtain the absolute brightness temperature of a black body of the moon, and the method has the advantages of high precision, low cost, easy popularization, and the like, and therefore, the method is suitable for being utilized as the methodfor calibrating high-temperature sources with full aperture by a satellite-borne large-caliber antenna microwave radiometer.

Description

technical field [0001] The invention relates to a calibration method suitable for ground-based microwave radiometer surface source moon measurement, and belongs to the technical field of microwave radiometer calibration. Background technique [0002] In the microwave and millimeter wave bands, in order to improve the sufficient spatial resolution of the satellite-mounted microwave radiometer to observe the earth, it has to use a large-caliber antenna to increase the antenna beam width. The antenna diameter often reaches several meters or even tens of meters, and the satellite body is difficult to carry. A blackbody of sufficient size to calibrate the whole radiometer can only rely on a small blackbody to calibrate the receiver at the rear end of the antenna at two points, while the exposed large antenna and sub-reflector cannot be accurately calibrated. Contents of the invention [0003] The purpose of the present invention is to find a suitable full-aperture calibration b...

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Problems solved by technology

[0002] In the microwave and millimeter wave bands, in order to improve the sufficient spatial resolution of the satellite-mounted microwave radiometer to observe the earth, it has to use a large-caliber antenna to increase the antenna beam width. The antenna diameter often reaches several meters or even tens of meters, and the satellite body is difficult to carry. A blackbody of sufficient size to calibrate the whole radiometer can only rely on a small blackbody to calibrate the receiver at the rear end of the antenna at two points, while the exposed large antenna and sub-reflector cannot be accurately calibrated

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