Image Integrity monitoring is a mechanism used to independently check that any image produced from a complex programmable GPU can be considered correct and consistent with the intended image output.
Rapidly evolving graphics display generation technology from the commercial PC industry provides low cost and exceptionally powerful solutions for implementing ever more capable and complex display systems. As the Graphics Processing Units (GPU) become increasingly complex, so does the associated driver and application code required to render an image on the screen.
This growing code size and complexity is problematic because the FAA and other international certification authorities mandate that the software be designed and tested to the DO-178C guidelines for flight critical airborne equipment in order to be certified for use in aircraft systems.
DO-178 certification requires that the software used to render flight critical data undergo exhaustive and carefully documented testing and verification procedures that are prohibitively expensive.
Further complicating the certification process is the fact that the low cost, high performance GPU from the PC industry do not have design history and verification data available from the manufacturer, nor has sufficient support data and testing been done by the manufacturer to demonstrate operational reliability and design integrity. This makes DO-254 certification of the hardware impossible.
We have extensive experience developing DO-178C DAL A certifiable Image Integrity Monitoring functions suitable for real-time verification of the Graphics Processing Unit (GPU) in the Cockpit Display System and ensuring that it is accurately rendering flight critical information for critical applications (e.g. Primary Flight Display) in the correct screen location, color, intensity and source data value.
This approach minimizes the level of DO-254 data for the GPU, and also allows the GPU driver and rendering software to be certified to a reduced Design Assurance Level than DAL A (typically DAL C).