基于冷空观测单元的综合孔径微波辐射计幅度定标方法  

Amplitude Calibration Method for Synthetic Aperture Radiometer Based on Cold-sky Observation Unit

作　　者：仝星 牛立杰 韩东浩 刘浩 TONG Xing;NIU Lijie;HAN Donghao;LIU Hao(National Space Science Center,Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院国家空间科学中心,北京100190 [2]中国科学院大学,北京100049

出　　处：《空间科学学报》2024年第5期832-845,共14页Chinese Journal of Space Science

基　　金：国家自然科学基金项目资助(42206185)。

摘　　要：微波辐射计通过定标获取目标准确的亮温,是数据定量化应用的必要手段.综合孔径微波辐射计由多个辐射计单元组成,定标需求从单一接收机扩展至所有接收单元.噪声注入是包括综合孔径微波辐射计在内的固定波束指向辐射计所常用的定标方法.作为定标参考的噪声二极管在轨会受到温度影响发生短期波动,并受器件老化影响发生长期漂移,从而导致系统定标精度恶化.针对上述问题,提出一种基于冷空观测单元的综合孔径辐射计幅度定标方法.通过设计专门的冷空观测辐射计通道,对综合孔径辐射计的公共噪声源进行实时标定,减小其噪声温度不确定性对综合孔径辐射计系统所有观测通道幅度定标的影响.结合中国海洋盐度探测卫星主被动探测仪中K波段一维综合孔径辐射计的实际系统方案,建立了辐射计系统模型及定标模型,开展了数值仿真及样机定标实验验证.仿真及实验结果验证了方法的有效性.Microwave radiometers obtain the accurate brightness temperature of the target scene through calibration,which is a necessary means for quantitative data application.The synthetic aperture microwave radiometer consists of multiple radiometer units,and the calibration requirement extends from a single receiver to all units.Noise injection is a calibration method for fixed antenna beam radiometers,including synthetic aperture microwave radiometers.However,the noise diode used as the calibration reference encounters issues such as short-term fluctuation caused by temperature and longterm drift resulting from the aging of the device,leading to the deterioration of the system's calibration accuracy.To address the aforementioned problems,this paper proposes a method of amplitude calibration for synthetic aperture radiometers based on a special cold-sky observation unit.By designing a dedicated cold-sky observation radiometer channel,the common noise source of the synthetic aperture radiometer is calibrated in real-time,reducing the influence of noise temperature uncertainty on the amplitude calibration of all observation channels in the synthetic aperture radiometer system.Based on the system scheme of the K-band one-dimensional synthetic aperture radiometer in the Microwave Imager Combined Active and Passive of China’s Ocean Salinity Detection Satellite,the radiometer system model and calibration model are established,and numerical simulations and prototype calibration experiments are carried out.Simulation and experimental results validate the effectiveness of the proposed method.

关 键 词：综合孔径微波辐射计 幅度定标 冷空定标 噪声注入 

分 类 号：TP73[自动化与计算机技术—检测技术与自动化装置]