A method for measuring sky brightness temperature in k-band

Abstract

The invention relates to a method for testing sky temperature at K band. The device used in the method comprises a K-band receiver, a bracket, a fixing frame, a rotating shaft, a bearing seat, an angle fixing nut, a first rotating shaft, a second rotating shaft, a first rotating table, a second rotating table, a normal-temperature blackbody, a high-temperature blackbody, and a high-temperature blackbody insulation cavity. The method comprises: calculating the response ratio of the strength and the temperature of the receiver by alternately introducing the normal-temperature blackbody and the high-temperature blackbody to a feeding surface of a separates K band receiver; removing the normal-temperature blackbody and the high-temperature blackbody to make the beam direction of the receiver toward cold sky at any elevation angle between 0-90 degrees, and recording the current radiation intensity; calculating the sky temperature at band at the current elevation angle by combining with thepreviously measured response ratio of the strength and the temperature of the receiver. The method for testing sky temperature at K band is not limited to the condition of clear night sky, can independently and quickly test the sky temperature at band at an elevation angle of 0-90 degrees, and provides real-time and accurate sky temperature values for intensity calibration in K band observations.

Description

technical field [0001] The invention relates to a method for testing the bright temperature of the K-band sky, in particular to an accurate and fast method for testing the bright temperature of the K-band sky in receiver intensity calibration, which is specially used for testing the bright temperature of the K-band sky. Background technique [0002] Radio astronomy is an important research field in modern astronomy. The purpose of intensity calibration in radio astronomy is to convert the response of any one receiving device to an astronomically observed source into an astronomical flux. The general calibration method is to use two radiation sources with different physical temperature broadband (such as cold and hot black body loads), place them respectively in front of the first stage amplifier or mixer of the receiver, and inject the radiation into the feed source or In the waveguide, this is used to calculate the noise temperature of the receiver. Once the noise tempera...

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Problems solved by technology

[0004] The main reason why the cold and hot load method test cannot be carried out during the observation process is that the cold load is inconvenient to use during the observation, so the related test is generally adjusted to the antenna elevation angle to 90 degrees before the observation, and is specially conducted by the receiver engineer , it cannot be implemented during the observation process

In addition, due to the different sizes of microwave components in different band receivers, the size of the feed source in the long centimeter band is too large. For example, the diameter of the feed source of the L-band receiver at Nanshan Station is 1.05 meters. Even using the cold and heat load method before observation is very difficult, because Difficult to provide a large enough cooling load to completely cover its feed port face

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