| 摘要 |
An improved aircraft instrument flight display system employs primary and secondary video graphics processors for generating graphics video imaging information. Both the primary and secondary video graphics processors have associated potential failure threads and are preferably chosen to have different potential failure threads so that the same failure problem will not have a tendency to occur in both of the video graphics processors. The primary video graphics processor generates a graphical display of the aircraft flight information for use by the flight crew in operating the aircraft. The system also includes a video switch for switching between the primary and secondary video graphics processors under control of the integrity checking processor based on the integrity of the graphical display provided by the primary video graphics processor. The switch switches its output to the secondary video graphics processor when the integrity checking processor detects a mismatch condition for the primary video graphics processor in order to maintain critical display data availability when a mismatch has been detected with respect to the primary video graphics processor. The video imaging information provided by the secondary video graphics processor can be a subset of the video imaging information provided by the primary video graphics processor or it can be the same. The integrity checking function may be accomplished by storing a complex checksum, such as a CRC, for a predefined image of each graphics image capable of being rendered as a baseline, and calculating an image checksum for the rendered image and comparing it against the stored complex checksum corresponding to the image for determining any deviations from the baseline. |
