星载太阳辐射监测仪的太阳程控跟踪精度

为了避免太阳敏感器(DSS)指向故障导致星载太阳辐射监测仪(SIM)功能失效,为风云三号(FY-3(03))卫星的太阳辐射监测仪(SIM)设计了备份跟踪方式程控太阳跟踪并分析了其跟踪精度。利用星上儒略日时间和卫星轨道瞬根,基于类基准地表辐射网(BSRN)算法推导了轨道坐标系太阳矢量、俯仰角和偏航角。将计算结果与卫星给定指向数据进行了比较。结果表明:太阳矢量三轴偏差均小于0.1°,俯仰角平均偏差为0.024 6°,偏航角平均偏差为-0.080 4°。对利用程序计算的多轨道指向数据进行了太阳模拟跟踪控制实验,结果表明:SIM俯仰跟踪控制精度优于0.1°,偏航跟踪控制精度优于0.05°。为保证在轨跟踪精度,试验了俯仰零点角和偏航零点角,其分别为80.46°和-36.96°。最终分析结果表明,俯仰程控跟踪不确定度为±0.318°,偏航程控跟踪不确定度为±0.316°,满足SIM太阳跟踪精度±0.5°的要求。设计的太阳程控跟踪降低了SIM对光学指向器件的依赖,提高了在轨太阳跟踪的可靠性。

Program-controlled sun-tracking precision of spaceborne solar irradiance monitor

To avoid the function failure of a solar irradiance monitor (SIM) caused by the pointing faults of the Digital Sun Sensor(DSS), the program-controlled sun-tracking of SIM on the FY-3(03) satellite was explored as the backup sun-tracking, and its precision was analyzed. By using the Julian day time and the satellite orbital parameters, the sun vector in orbital coordinate system, pitch angle and the yaw angle were deduced on the basis of Baseline Surface Radiation Network(BSRN)-like algorithm. The calculated results were compared to that of the satellite-given sun-pointing data, it shows that the sun vector deviations in three axes are all less than 0.1°, and the average deviations of pitch angle and yaw angle are 0.024 6° and -0.080 4° respectively. Using the program-calibrated sun-pointing data of many orbits, a sun-tracking control simulation experiment was carried out, and the results show that the pitch tracking control precision is better than 0.1°, and the yaw tracking control precision is better than 0.05°. To guarantee the on-orbit tracking precision, the pitch zero-position angle and the yaw zero-position angle were measured, and they are 80.46° and -36.96° respectively. The final analysis results show that the pitch tracking uncertainty is ±0.318° and the yaw tracking uncertainty is ±0.316°, meeting SIM sun-tracking precision requirement of ±0.5°. The proposed program-controlled sun-tracking reduces the dependence on the optical pointing devices, and improves on-orbit sun-tracking reliability.