Fault Tolerance And Recovery Design Of CubeSat Onboard Computer Based On Software Redundanc

With the advantages of low cost,high integration and short development cycle,Cube Sats have become a hot spot for development in the space field.As one of the core components of the Cube Sat,the reliability of the on-board computer is affected by various radiation effects generated by high-energy particles in the space environment.Due to energy and space constraints,the traditional methods to improve the reliability of on-board computer based on hardware redundancy cannot meet the needs of Cube Sats,so improving the reliability of onboard computer by software means has become a research hotspot in the field of space and has important application value.Aiming at improving the reliability requirements of on-board computer,a multi bit error detection and correction scheme is designed,and based on the single board heterogeneous dual core structure system,a highly reliable on-board computer fault tolerance and recovery scheme for Cube Sats is proposed to support system recovery by both software triple modular redundancy boot and on-line reconfiguration.The main research of this paper is as follows.EDAC detection and error correction scheme based on Extended Hamming code and CRC cyclic redundancy code is designed.Aiming at the problem that the traditional detection and error correction algorithm can only realize single bit correction and double bit detection,the CRC cyclic redundancy code is used for error detection,and the combined row column Extended Hamming code scheme is designed for error correction.The detection and correction ability of the scheme under different error bit modes is analyzed,and it is verified that the scheme can completely detect and correct error bits of 3 bits and below.The on-board computer system and on-board software fault tolerance and recovery scheme based on ARM + FPGA single board heterogeneous dual core structure are designed.The fault tolerance and recovery schemes of software boot and on-line reconfiguration are proposed respectively for the two startup modes of on-board software.The software boot scheme is based on software three module redundancy,which realizes the verification and recovery of on-board software,and ensures that the system goes into the normal operation process.The online reconfiguration scheme enables re-burning of the on-board software through a set reconfiguration process,and the on-board software is maintained reliably through the EDAC scheme.Finally,the reliability analysis is carried out based on Markov theory model.The results show that the system meets the reliability requirements of design life.The software and hardware design of the fault-tolerant and recovery system of the onboard computer are completed,and the function test and the thermal vacuum reliability environment test at the appraisal level are carried out to verify the feasibility of the designed fault-tolerant and recovery scheme.The on-orbit data proves that the on-board computer has the ability to work normally in the space mission environment.