<title>Enhanced spatial-state feedback for night-vision goggle displays</title>

Abstract

A preliminary study was conducted to investigate the use of visual flow cues as an aid to ground and vertical drift awareness during helicopter flight and targeting while using night vision goggles (NVG&apos;s). Three displays were compared: 1) NVG display: simulated NVG image of cockpit and external environment; 2) Overlay display: NVG image with an overlay of a flow cue field and a surrounding wire-frame globe; 3) Cut-out display: same as the Overlay display but with symbology removed from the central region (leaving an unobscured 20 degree field-of-view of the NVG image). Three levels of contrast were also compared using each display type. The visual scenery was displayed to subjects using a helmet-mounted virtual reality device that had a 40 X 50 degree field-of-view liquid crystal display The study involved six pilots. Three tasks were given: 1) Search task: designate enemy targets with a helmet-mounted sight (no flight control inputs); 2) Hover task: null out all translational and yaw rates while in a hover; 3) Search/Hover task: perform both Search and Hover tasks simultaneously. These tasks were conducted in a fixed-based helicopter simulator which used the dynamics of a small-scale model helicopter. The following performance measures were collected: 1) Pilot ability to detect and recognize targets (Search and Search/Hover tasks); 2) Pilot ability to null translational and yaw rates (Hover and Search/Hover tasks); 3) Time scanning the instrument panel (Hover and Search/Hover tasks). Subjects also rated displays for efficacy in completing the three tasks.