L波段微波辐射计冷空定标源亮温分析

欧空局SMOS任务的塔克拉玛干沙漠地面定标实验，采用L波段微波辐射计测量塔克拉玛干沙漠的土壤亮温。此辐射计的定标采用冷空作为低温定标源。由于冷空的情况比较复杂,在L波段,其亮温受到诸多因素的影响。根据日地关系、太阳与天线的位置关系，建立太阳辐射模型，得出了任意时刻太阳进入天线视场范围内的影响亮温值,并简要分析了月球、其它星球、中性氢原子分立谱发射和热源连续谱发射对辐射亮温的影响，为选取冷空作为低温定标源提供了理论及数据参考。

Analysis of the Cold Sky Brightness Temperature of L-band Radiometry Calibration

The ground calibration experiment for ESA's SMOS Mission will use an L\|band radiometry to measure soil brightness temperature of Takelamagan Desert.This radiometry's calibration "cold" target is cold sky.Because of the complex condition,in L-band,many factors have effect on brightness temperature of cold sky.This issue establishes a sun radiation model to calculate real\|time brightness temperature when it crosses the view field of antenna to the position relationship between sun and earth， also between sun and antenna.It analyzes briefly the radiometric temperature under the influences of moon,planets in our solar system and galactic radio emission.This issue provides theoretical and numerical reference for choosing the cold sky as "cold" target in calibration.