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A brief study has been conducted to investigate several visual anomalies reported by test pilots using a Display Night Vision Goggle (DNVG) that superimposed symbols onto the intensified image seen by the right eye. A survey of relevant research suggests that one oddity, an apparent focus mis-match between the scene image and the injected symbols, is an irremovable facet of the perception of bright, contrasting, overlaid symbols. A second oddity, an uncomfortable and distracting blurring of the under-stimulated left eye during periods of flight in cloud, was eventually experienced by several people in a laboratory simulation, the effect being more noticeable if the under-stimulated eye was the dominant eye. A subsequent apparent enlargement of the HUD symbols and a post-flight focussing delay by the left eye seemed to be after-effects of whatever caused the ocular discomfort. As about 30% of the population are left eye dominant, the disturbing discomfort and aftermath could affect this proportion of pilots using a right-eye DNVG. Although further work is needed to understand the phenomena, it would be wise to warn aircrew and enable the symbol injection unit to be fitted to either channel of the DNVG.

This paper describes the Virtual Environment Integration Laboratory (VEIL) of the Royal Aerospace Establishment (RAE). The VEIL programme is intended to provoke appropriate technological developments by exploring the human requirements of operating within a virtual cockpit whilst conducting demanding missions. Under construction is a light-weight binocular, colour helmet-mounted display with a wide field of view, driven by a versatile parallelarchitecture computer graphic system which accommodates simulated sensor images from a camera and terrain model. Prototypes of suitable display formats will be developed using a bench-mounted stereoscopic viewing rig which will also facilitate investigation of critical psychophysical issues. The complete VEIL hardware will integrate eye and head position sensors, three dimensional sound, direct voice input, and tactile sensors with the binocular display system. When allied to the ground-attack, helicopter and air-combat simulator facilities of Mission Management Department, it will enable the practicality of operating virtual cockpit systems in a wide variety of missions and tasks to be addressed.