星载软件的语句级高效更新方法

为减少星载软件在轨更新过程对测控资源的需求量,缩短更新上注时间,提出了一种无需操作系统支持、上注数据量低、版本可灵活控制的语句级软件更新方法。该方法首先利用预编译命令进行程序空间优化,使得不同模块的代码在编译后存储于不同的段中,减少代码修改对加载文件的影响；其次通过逐段求解参考段与更新段之间匹配路径,并基于此进行各段的差异内容提取,大大降低差异补丁规模；然后通过版本引导程序设计,实现对卫星软件版本的灵活控制；最后通过对文件和程序进行可靠性设计,保证整个更新过程的安全性。结果表明:该方法在ZDPS-3A卫星平台进行了充分的测试,所提出的更新方法可应用于无操作系统的星载计算机,支持软件状态可回滚且更新过程可靠,同时相比传统的差异内容提取方法,补丁文件的规模降低量均值超过50.00%,可显著缩短更新上注时间。本方法能够充分满足星载软件低数据量更新的需求,可推广应用至包括微小卫星在内的多种航天器。

Efficient statement-level update method for on-board software

To reduce the demand for telemetry, tracking, and command (TT&C) resources in the on-orbit software update process and shorten the update upload time, this paper proposes a statement-level software update method that requires no operating system support, has a small amount of upload data, and can be flexibly controlled. Firstly, precompiled command was used to optimize the program space to make the code of different modules stored in different segments after the compilation, so as to reduce the impact of code modification on the loaded file. Secondly, the matching path between the reference segment and the update segment was solved segment-by-segment, and the difference content of each segment was extracted, which could greatly reduce the size of the differential patch. Thirdly, through the design of version guidance program, the flexible control of satellite software version was realized. Finally, the reliability design of the files and the program was performed, which could ensure safety of the entire update process. The method was fully tested on the ZDPS-3A satellite platform. Results show that the update method proposed in this paper could be applied to on-board computers without operating systems. The software state could be rolled back and the update process was reliable. Besides, compared with the traditional method of extracting different content, the average reduction of patch file size generated by this method was more than 50.00%, greatly shortened the update upload time. Therefore, the proposed method can meet the demand for low volume data update of on-board software and can be applied to other spacecrafts such as micro-satellites.