地基、空基、星基微波辐射计定标技术概览

A Review:The Calibration of Ground-based,Airborne and Satellite-borne Microwave Radiometers

微波辐射计是用于测量物体微波辐射能量的被动遥感仪器 ,在军事、环境科学上都有极大的作用。如果用于工作的微波辐射计没有经过统一、精确、可靠的定标和校验 ,各自测得的结果将十分混乱 ,所以定标技术是微波辐射计研究、应用中的关键课题之一。在不同的使用条件下 ,微波辐射计的定标有不同的技术要求和难点。按运载平台的不同 ,系统地阐述了微波辐射计定标技术的国内外研究现状和发展趋势 。

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.