星锁异常分析方法及处置策略

Satellite Lock Anomalies and Handling Strategies

扩频模式星锁指示是判断上行信号锁定与否的重要参数,它是关系到双捕能否完成的关键。针对地面测控设备跟踪某遥感卫星时星锁异常的问题,采用FTA（故障树分析法）从星地两方面查找原因,找出了造成星锁异常的主要因素是扩频应答机下行测量帧中CRC（交叉冗余码校验）计算错误,诱因归结为扩频应答机FPGA（现场可编程门阵列）存储器中程序码受SEE（单粒子效应）干扰所致。提出一种针对性处置策略,为后续星的工程应用提供切实可行的途径。

Satellite lock sign in spread spectrum mode is a very important parameter for judging the lock of an uplink signal and it is the key for successful bi-directional capture.FTA（Fault Tree Analysis） method is used to identify the causes of satellite lock anomalies from both the satellite and ground TT＆C equipment.It is found out that the main reason of satellite lock anomaly is CRC（Cyclic Redundancy Check） computation error in the downlink measurement frames of the spread spectrum transponder,and the root reason is the interference of SEE（Single Event Effect） on programs in the FPGA memory.A handling strategy is given to avoid similar anomalies in follow-up satellite projects.