FY-3卫星微波辐射热定标源设计与性能分析

基于FY-3卫星微波辐射热定标源周期性阵列角锥结构,采用时域有限差分算法(Finite Difference Time Domain,FDTD),对其发射率进行仿真分析,并采用空间驻波法(Space Standing Wave Method,SSMW)进行测试。计算表明:热定标源发射率随吸波涂层厚度的增加逐渐提升,但趋于稳定;随着中心频率的增加,热定标源发射率逐渐增大,在典型涂层厚度1 mm 参数下,工作频段内发射率已大于0. 999。测试结果表明:热定标源在工作频段内发射率大于0.995。综合地面热真空试验以及在轨测试结果,表明热定标源辐射面温度均匀度满足设计指标±0.25K的要求;在轨工作时,由于热定标源辐射面与深空背景辐射热量交换更为剧烈,从而导致其辐射面温度均匀度大于地面测试结果。该项研究为FY-3 后续型号以及其它型号星载微波辐射热定标源产品的升级换代提供工程应用基础。

Design and Performance Analysis of FY-3 Satellite Microwave Radiant Thermal Calibration Source

Based on the periodic pyramid structure of the FY-3 satellite microwaves radiation, the FDTD (Finite Difference Time Domain) is used to simulate the emissivity,as well as the SSWM(Space Standing Wave Method)is used for testing. The calculated results show that the emissivity of the thermal calibration source gradually increases with the thickness of the absorbing coating, but tends to be stable; The emissivity of the thermal calibration source increases gradually with the increase of the center frequency. In the typical coating thickness of 1mm, the emissivity in the working band is more than 0.999 by calculation,while the test result is greater than 0.995. The results show that the uniformity of the radiation surface of the thermal calibration source satisfies the requirement of ±-0.25K of the design specification. The temperature uniformity of the radiating surface is greater than that of the ground test results due to the more intense heat exchange between the radiant surface of the thermal calibration source and the deep space background in orbit. This study provides the engineering application basis for the upgrading of FY-3 follow-up models and other models of spaceborne microwave radiant thermal source products.