Since the early 1940s the number of displays and controls per aircraft has rapidly increased (Fig I), simultaneously system complexity has increased dramatically (Fig 2) and the number of crewmen per system platform has been decreasing Ways of alleviating operator workload in this deteriorating situation have had to be found Part of the answer has been in automation and in the change from "stand alone systems", as currently used on ships, to "integrated systems" and to full ‘3ystems integration’
However, all this counts for nothing if the original system design is incorrect, and to avoid this a rigorous, structured design methodology called controlled operational requirements expression (CORE) has been employed This methodology is used to provide structured requirements and design It has several clearly defined levels, each of which was audited at the completion of that level, the production of CORE diagrams was also automated Thus the design process is highly visible and can be validated all the way from high level requirements down right down to software coding level CORE forces the engineer to differentiate between a "requirement", such as the ability to navigate, and the "implementation of that requirement" As an example, when CORE was retrospectively applied to Tornado, it resulted in a massive decrease in the number of gyroscopes carried on the aircraft.
To get the initial requirement correct a Fast Prototype of part of the Man-Machine Interface for a ship command centre was built using commercially available equipment, while the design process was still at a high level and well before any design freeze The advantages of this were that the designers, customer, and users could see a simulated working system in operation. A consultative process then eliminated design errors and refined the system long before the design freeze On a system being taken to completion, the finalized requirement for the equipment may then be written, which in turn leads to the equipment specification and to building of the real equipment.
The current rapid increase in aircraft systems complexity causes difficulty in both defining and implementing the system requirement Errors in the requirement and in (Fig. 1 and Fig. 2 are available in full paper) the implementation of the requirement, inevitably led to an extension in the timescales and cost required for system development. An effective method of defining the requirement is by using fast prototyping and simulation software.
There is little problem in defining the requirement if the system being designed is similar to a previously produced system. However, given the rapid developments in the field of avionics and the long gestation period of fighter aircraft, the system being designed will bear little relation to its predecessor. Additionally, little of the hardware and none of the software will exist, and so the designer has a real problem in sensibly defining the requirement.
It was realized early on in the CORE design exercise that three multifunction displays would be required for the main command and control positions. The formats for these were developed on a format generator (Fig. 3). In the initial stages the architecture was fairly rudimentary, allowing only static formats to be represented, but format layout, symbology, and colour usage were investigated. The interface for the format generator used is very user friendly, allowing bitpad and mouse inputs.
