Abstract: The time tagged data are directly related to whether the task can be realized, which is very important for a satellite. The time tagged data are executed according to the timetable and often stored in on board computer for a long time. Fault tolerance design is needed to mitigate the influence of single event upsets. By function,the time tagged data which has different length can be classified as Time Tagged Telecommand, Time Tagged Data Block, and Relative Time Tagged Telecommand. An SEU mitigation method of time tagged details is proposed. Error correction coding and frame annotation for time tagged data of different length are done on the ground, and the information bits and the supervision bits are checked by the on board computer periodically or before the data to be used. The error correcting capability of the new method does not  rely on hardware and is better than the traditional three mode redundancy method, and the memory space can be saved greatly.

Key words: time tagged data, single event upsets (SEU), error detection and correction (EDAC)