So-called synthetic vision systems are regarded as a candidate technology to increase safety and/ or enable operations that are impaired by reduced visibility conditions. Although there is no single agreed upon definition of synthetic vision, the common element in almost all definitions and implementations is a computer generated depiction of the environment as seen from the cockpit based on spatioal data. Some of the ideas date back to almost fifty years afo, long before the term synthetic vision was coined. The implementation of prototype synthetic vision systems on board aircraft started in the early nineties, enabled by the advances in the area of accurate real-time position determination, data storage and real-time spatially integrated data presentation. This paper discusses the concept, design and evaluation of a system that during the last five years has been flight tested on board six different aircraft, ranging from twin-turboprop to widebody jets. The discussion on the design rationale comprises the guidance and control task, situation awareness and data integrity monitoring using integration of imaging sensor data.@en

The basis for synthetic vision was established long before the term was coined. During the Eighties, extensive simulator evaluation using displays that presented a computer-generated, spatially integrated depiction of the environment, the planned path and threat areas, was performed. The anticipated advantages that were pursued comprised a reduction in signature made possible by a reduction in the use of active sensors and an increase in pilot situation awareness because of the integration of information regarding threat areas. In the early nineties, a proof-of-concept demonstrator was realized in which the combined use of database technology, advanced displays and forward-looking sensors has been explored to provide aircraft a nap-to-earth navigation capability. This paper describes the design and evaluation of a synthetic and enhanced vision system that has been extended with functions to provide a database derived terrain following capability, both on planned routes and off path. It will discuss the guidance cues implemented to provide both on-path and off-path TF guidance, illustrate how the integration of real-time imaging sensor data is ised to compensate for the limitations of the terrain elevation database, and show how information regarding known threats is integrated into the different displays. Furthermore, initial results from a flight test performed with the FAA 727 are presented.@en