A Review:The Calibration of Ground-based,Airborne and Satellite-borne Microwave Radiometers
地基、空基、星基微波辐射计定标技术概览

It has been proven that there exists heat radiation from any object whose temperature is greater than absolute zero by therories and studies.Brightness temperature is usually adopted to describe this radiation characteristic,which varies with the geometry and dielectric characteristics of targets.Microwave radiometer is a category of instrument,which is applied to measure the heat radiation characteristic of one target and very useful in observing the earth from satellite.In fact,it is one receiver with high sensitivity since the radiation signal is extremely weak,even weaker than the receiver background noise.This receiver consists of antenna,broad bandwidth receiver,and data recorder.Studies in the past have shown that the collected data are of very confusion if microwave radiometers are not calibrated and validated before application,so microwave radiometer calibration techniques are very important.Microwave radiometers can be utilized on ground-based,airborne and satellite-borne platforms,and there are different demands and difficulties about microwave radiometer calibration accordingly,so it is necessary to discuss the calibration on different platforms.In this paper,the calibration techniques of ground-based,airborne and satellite-borne microwave radiometers are discussed,and some problems are also mentioned.