A method of determining a corrected control surface angle for use in
single viewpoint photogrammetry to correct control surface angle
measurements affected by wing bending. First and second visual targets
are spaced apart from one another on a control surface of an aircraft
wing. The targets are positioned at a semispan distance along the
aircraft wing. A reference target separation distance is determined using
single viewpoint photogrammetry for a "wind off" condition. An apparent
target separation distance is then computed for "wind on." The difference
between the reference and apparent target separation distances is
minimized by re-computing the single viewpoint photogrammetric solution
for incrementally changed values of target semispan distances. A final
single viewpoint photogrammetric solution is then generated that uses the
corrected semispan distance that produced the minimized difference
between the reference and apparent target separation distances. The final
single viewpoint photogrammetric solution set is used to determine the
corrected control surface angle.