摘要
针对双通道噪声相加型辐射计存在的视频信号处理电路复杂、系统稳定观测时间缺乏定量分析等问题,结合目标辐射特性测量需求,改进了一种测量目标辐射特性的W波段辐射计。该辐射计采用基于直接数字采样的视频信号处理方法,在降低视频信号处理电路复杂度的同时,增加了系统的灵活性。结合短周期定标技术与Allan方差分析方法,建立了目标亮温测量方程并推导了系统的理论灵敏度,在实现接收机稳定性评估的基础上确定了系统稳定观测时间。实验结果表明,设计的辐射计在积分时间为1s时灵敏度为0.3K,系统稳定观测时间可达40s,在0°-70°天顶角范围内对天空观测亮温与理论计算差值小于2.6K,系统整体性能指标优于双通道型噪声相加型辐射计。
In view of the requirement for target radiometric characterization and the problems of the dual-channel noise-adding radiometer like the complicated video signal processing circuits,and the lack of quantitative analysis for the stable observation time,an improved W-band radiometer is proposed for radiometric characterization.A video signal processing approach based on the direct digital acquisition is employed to reduce the complexity and strengthen the flexibility of the system.The object brightness temperature measurement equation is established and the system theoretical sensitivity is derived by combining the short periodic calibration technique and Allan variance analysis.Also the stable observation time is determined by the stability evaluation of the system.The experimental results show that the sensitivity of a designed radiometer is 0.3Kwith an integration time of 1s,the available stable observation time is able to reach to 40 sand the difference between the measurement and theoretical calculation of the sky brightness temperature is less than 2.6K within a zenith angle range of 0°-70°.The overall performances of the proposed system are superior to that of the dual-channel noise-adding radiometer.
出处
《系统工程与电子技术》
EI
CSCD
北大核心
2016年第7期1502-1507,共6页
Systems Engineering and Electronics
基金
国家自然科学基金(61301213
61501234)
江苏省自然科学基金(SBK20130768)资助课题
