低轨互联网卫星在轨单粒子翻转分析及防护措施

空间单粒子翻转（SEU）对于在轨卫星寿命和可靠性有着较大的影响，然而，针对低轨互联网卫星1000～1200 km的典型极地轨道空间SEU，目前缺少在轨试验验证结果。文章对某型号的两颗卫星在轨7个月以来的SEU事件记录数据进行处理和分析，给出互联网卫星1050～1425 km不同轨道高度上的SEU事件发生的频度、区域及概率，结合在轨运行情况提出互联网卫星在轨单粒子翻转的软硬件防护设计措施。数据表明，在当前低轨互联网卫星的典型轨道高度上，对于抗单粒子翻转阈值为0.7 MeV·cm2/mg的低阈值SRAM器件，在轨SEU事件大部分发生在SAA区域，发生概率约为7.63×10-7 bit-1·d-1。结合卫星在轨空间防护设计经验，通过加强元器件选用控制、软硬件冗余设计、关键器件限流等措施，可以有效提高低轨互联网卫星的在轨可靠性。

Analysis of in-orbit single event upset of low-Earth-orbit internet satellite and protection measures

The single event upset (SEU) of low-Earth-orbit (LEO) satellites has a great impact on the lifetime and the reliability of the in-orbit satellites. But the in-orbit verification results are few for the SEU of the internet satellite at a typical polar orbit altitude in the range of 1000 km to 1200 km. This paper analyzes and processes the SEU record data of the two satellites in-orbit for seven months, and gives the frequency, the area and the orbital heights of SEUs at different orbital altitudes from 1050 km to 1425 km for the internet satellites. It is shown that the probability of the in-orbit SEU for the onboard SRAM is about 7.63×10-7 bit-1·d-1, and most in-orbit single event upsets occur in the South Atlantic Anomaly (SAA) area. And it is shown that the reliability of the LEO internet in-orbit satellites can be effectively improved by strengthening the control of the component selection, the software and hardware redundancy design and the current limiting of the key components.