Method for testing sky brightness temperature of horn antenna

Abstract

The invention relates to a method for testing the sky brightness temperature of a horn antenna. The method comprises the steps of obtaining the power and temperature response ratio of a receiver through a normal-temperature and high-temperature load method, obtaining the noise temperature of the receiver through a theoretical calculation mode, and testing the power output of the receiver when a normal-temperature load covers the aperture of the horn antenna, acquiring the ground noise temperature of the receiver at the current elevation angle by combining the power and temperature response ratio and the theoretical noise temperature of the receiver, and then by testing the power output of the receiver corresponding to the sky radiation at the current elevation angle and combining the obtained power and temperature response ratio, the theoretical noise temperature of the receiver and the tested ground noise temperature, accurately calculating the sky brightness temperature under the current elevation angle. According to the method, the receiver power and the temperature response ratio can be obtained without depending on a low-temperature load which is not easy to operate, and ground noise generated by antenna side lobes and back lobes of a horn antenna main wave beam within the elevation angle of 0-90 degrees is tested, so that the sky brightness temperature is accurately separated from the system temperature; the method is directly applied to research work such as receiver strength calibration and atmospheric opacity measurement.

Description

technical field [0001] The invention relates to a method for testing the brightness temperature of the sky with a horn antenna, which is specially used for research work such as receiver intensity calibration and atmospheric opacity measurement in the field of radio astronomy. Background technique [0002] In the field of radio astronomy, there are many receiver intensity calibration methods, among which the chopper wheel calibration method is to alternately introduce and remove a normal temperature black body on the top of the receiver feed horn, so that the receiver can alternately test the radiation of the normal temperature black body and the sky, This is how you test receiver noise temperature. Its principle is the same as the traditional cold and hot load method, except that the black body load (cold load) soaked in liquid nitrogen, which is not easy to use in this method, is replaced by the sky. During the test, it is only necessary to alternately introduce or remove ...

AI Technical Summary

Problems solved by technology

In order to accurately obtain the average temperature of the atmosphere, it is necessary to combine a large number of meteorological parameters, such as the partial pressure of water vapor after atmospheric stratification, atmospheric temperature, etc., which makes it very difficult to solve the sky brightness temperature

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