Ensuring Software Quality-Experiences of Testing Tejas Airdata Software

摘要

Two major safety-critical elements of the onboard software for the Tejas digital flight control computer software are the control laws and the airdata algorithm. The airdata algorithm computes essential parameters like static and dynamic pressures, altitude, speed, angle of attack, etc from the airdata sensor input. These parameters are used by the control laws to stabilise the aircraft and to provide the required uniform handling qualities over the complete flight envelope. The algorithm is provided by the Control Law Design Team and coded by the Software Design Group of Software House, ADA, Bangalore, in Ada language. The Independent Verification and Validation Group is responsible for ensuring that the software is bug-free and certifiable. A non-real time (NRT) test methodology has been developed in-house to stress test the onboard software. This paper gives an overview of the methodology used to carry out the NRT test of the airdata algorithm and some of the testing experiences.