A storage strategy based on "three-level data storage

three-mode fault-tolerant structure" is proposed to improve the performance and the reliability of the data storage system for nano-pico satellites. Firstly

the storage device is selected based on the analysis of the onboard storage media and fault characteristics. After analyzing the error sources of the file system

a scheme combining the ECC error correction

the redundancy backup and the current protection is applied to improve the reliability of the system. The file space is pre-allocated and a ring data storage structure is established to reduce errors and decrease the operating complexity for the file system. Finally

taking the advantages of RAM

FRAM and SD card

a three-level data storage method is utilized to improve the storage speed and the fault tolerance. writing speed increases by about 4.7 times when the data size is 1 MB

and the SDC abnormality or abrupt power-off of the system can not affect the system; in addition

the fault switching time is less than or equal to 10 ms when the fault switching time is less than or equal to 1 frame. In orbit operation process

all the FS

files and the storage media work well. The ground test and the in-orbit operation show that the proposed data storage strategy is feasible

and the system reliability and the performance of data reading and writing can meet the mission requirements of satellite system.