Testing of Real time Embedded Onboard Software : a Launch Vehicle Case Study

The avionics system in safety critical aerospace systems plays an extremely important role in ensuring proper performance as well as safety of the mission. The Onboard Computer (OBC) that functions as the master in the avionics bus in launch vehicles is based on an indigenous processor. The development and testing of the Real Time Executive (RTE) software for the OBC, satisfying all requirements is a daunting task. This work describes the testing techniques employed for the RTE software in the reusable launch vehicle. Various dynamic testing techniques like unit testing, integration testing and system testing were employed to validate the OBC software. Validations were also carried out for the entire system utilizing different test beds, where all the subsystems are connected. In addition, the software was subjected to code inspection and rigorous reviews which constitutes static testing. The results of testing the onboard software are also elaborated. Subsequent to detailed analysis of all test results and incorporation of necessary corrections, the software was cleared for final flight use and its performance was normal in flight.