The visually guided control of simulated altitude
Johnson, W.W.; Tsang, P.S.; Bennett, C.T.; Phatak, A.V.
Aviation Space and Environmental Medicine 60(2): 152-156
1989
ISSN/ISBN: 0095-6562 PMID: 2930427 Document Number: 328938
Simulated "flights" over three different ground textures were used to examine people's ability to extract optical information useful for active regulation of altitude. The textures were regularly spaced lines as follows: 1) orthogonal to the direction of flight (latitude textures); 2) parallel to the direction of flight (meridian textures); and 3) both parallel and orthogonal (square texture). Visual constant velocity forward flight simulations were displayed on a CRT screen, and subjects asked to maintain one of three initial altitudes using a rate control stick. This task was made difficult by the presence of lateral (irrelevant) and vertical (relevant) "wind gusts". The attitude never varied as winds, forwards speed, and vertical rate control resulted in only translational movements. Adjusted root mean square errors (ARMSE) showed altitute regulation was more difficult at higher altitudes and when flying over meridian textures. Refined analysis of a single subject's data showed that his was due both to poorer regulation of the vertical wind disturbance and to a tendency to confuse the lateral wind disturbance for a vertical disturbance.