title: Sustained acceleration on perception of relative position and motion.
abstract: BACKGROUND
  Air-to-air refueling, formation flying, and projectile countermeasures all rely on a pilot's ability to be aware of his position and motion relative to another object.
  
  
  METHODS
  Eight subjects participated in the study, all members of the sustained acceleration stress panel at Wright-Patterson AFB, OH. The task consisted of the subject performing a two-dimensional join up task between a KC-135 tanker and an F-16. The objective was to guide the nose of the F-16 to the posterior end of the boom extended from the tanker, and hold this position for 2 s. If the F-16 went past the tanker, or misaligned with the tanker, it would be recorded as an error. These tasks were performed during four G(z) acceleration profiles starting from a baseline acceleration of 1.5 G(z). The plateaus were 3, 5, and 7 G(z). The final acceleration exposure was a simulated aerial combat maneuver (SACM).
  
  
  RESULTS
  One subject was an outlier and therefore omitted from analysis. The mean capture time and percent error data were recorded and compared separately. There was a significant difference in error percentage change from baseline among the G(z) profiles, but not capture time. Mean errors were approximately 15% higher in the 7 G profile and 10% higher during the SACM.
  
  
  CONCLUSIONS
  This experiment suggests that the ability to accurately perceive the motion of objects relative to other objects is impeded at acceleration levels of 7 G(z) or higher.
authors.affiliation: Air Force Research Laboratory, Applied Neuroscience Branch, 2510 Fifth St., Bldg. 840, Wright-Patterson AFB, OH 45433, USA. andy.mckkinley@wpafb.af.mil
authors.forename: R Andrew
authors.initials: RA
authors.lastname: McKinley
authors.forename: Lloyd D
authors.initials: LD
authors.lastname: Tripp
authors.forename: Kathy L
authors.initials: KL
authors.lastname: Fullerton
authors.forename: Chuck
authors.initials: C
authors.lastname: Goodyear
mesh_terms: D000054:Acceleration; D000328:Adult; D001359:Aviation; D003198:Computer Simulation; D005260:Female; D005676:Gravity Suits; D006801:Humans; D018471:Hypergravity; D008297:Male; D008889:Military Personnel; D013647:Task Performance and Analysis