近地轨道高精度一体式星敏感器热设计及仿真验证

Thermal Design and Simulation Verification of High-precision Integrated Star Sensor in Near-Earth Orbit

某型高精度一体式星敏感器指向精度高,对温度变化非常敏感。其所处近地轨道外热流复杂多变,一体式结构和内热源集中的综合因素不仅导致散热设计困难,而且镜头直接受到内热源发热影响难以保障指向精度。首先,结合轨道参数,安装布局获得星敏感器平均吸收外热流。然后,通过分析外热流与内热源工作情况,采用被动热控和主动热控相结合的热设计方法,并对星敏感器散热面的位置与大小进行设计与计算。最后,根据轨道环境和热控措施并利用热仿真软件进行热分析验证。仿真结果表明,安装法兰温度为19.82℃~20.10℃,镜头轴向温差小于2.23℃,周向温差小于0.48℃,电路盒温度为19.10℃~23.49℃,满足热控指标。通过合理的热控设计保证了极高精度星敏感器的稳定工作条件,星敏感器的热设计合理有效。

High-precision integrated star sensors have a high pointing accuracy and are highly sensitive to temperature changes.The external heat flow in near-Earth orbits is complex and variable.The comprehensive factors of the integrated structure and the concentration of the internal heat source not only lead to difficulty in the heat dissipation design,but also make it difficult to guarantee the pointing accuracy of the lens directly affected by the internal heat source.First,combined with the orbital parameters,the installation layout provides the average absorbed external heat flux of the star sensor.Subsequently,by analyzing the working conditions of the external and internal heat flows,a thermal design method combining passive and active thermal control is adopted,and the position and size of the heat dissipation surface of the star sensor are designed and calculated.Finally,thermal analysis and verification are performed using thermal simulation software according to the orbital environment and thermal control measures.The simulation results show that the installation flange temperature is 19.82-20.10℃,the axial temperature difference of the lens is less than 2.23℃,the circumferential temperature difference is less than 0.48℃,and the circuit box temperature is 19.10-23.49℃,which meets the thermal control index.The stable working conditions of the extremely high-precision star sensor are ensured by a reasonable thermal control design,and the thermal design of the star sensor is reasonable and effective.