Effect of "Inside-Out" and "Outside-In" Attitude Displays on Off-Axis Tracking in Pilots and Nonpilots

David Cohen, B.A., M.S., Shinji Otakeno, M.D., Fred H. Previc, M.S., Ph.D., and William R. Ercoline, B.S., M.S.
Aviat Space Environ Med 2001; 72:170-6

Abstract

Background: Pilots employing helmet-mounted displays spend sustained periods of time looking off-axis, necessitating the inclusion of attitude symbology on the helmet to maintain spatial awareness. We examined how fundamentally different attitude references, a moving-horizon ("inside-out") or a moving-aircraft ("outside-in"), affected pilot and nonpilot attitude control when looking on- or off-axis. Both a rear-view and a side-view outside-in perspective were depicted to investigate the effect of control-display compatibility. Methods: Subjects performed a compensatory pitch-roll tracking task either looking on-axis or 90° off-axis using three symbologies: 1) a compressed pitch ladder with horizon line; 2) a 3-D aircraft representation viewed from the rear; and 3) a 3-D aircraft representation viewed from the side. Tracking error in roll and pitch, control bias, and subjective ratings were collected and analyzed. Results: There was no significant difference in the tracking performance of U.S. Air Force pilots in pitch and roll using the inside-out or outside-in rear-view formats on- and off-axis, although they preferred the inside-out format. Nonpilots tracked significantly better using the outside-in rear-view format, which they also preferred. Both groups tracked poorly using the outside-in side-view format and control-display compatibility had no important effect. Conclusions: Pilots are equally adept using outside-in and inside-out displays. Given that an outside-in display may better reflect a person's inherent frame of reference for orientation (as evidenced by the nonpilots' superior performance with it), the results seem to indicate that pilots, through experience, have adapted to an inside-out frame of reference.

Keywords: spatial disorientation, situation awareness, attitude displays, helmet-mounted displays, tracking, control-display compatibility.

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Table of Contents for Volume 72, Number 3 of the ASME journal.