Numerical processing of dynamic subaperture testing measurements.

Subaperture testing is a technique for interferometrically testing optical telescopes with an array of small flats rather than the usual single large flat. Special subaperture testing analysis algorithms are then required to remove the effects of small misalignments of the subaperture flats. Classical subaperture testing theory treats the analysis of measurements or interferograms one frame at a time. This paper covers the case where a series of measurements are taken over a period of time. This paper begins with a description of the static subaperature testing problem and a review of classical solutions. The dynamic subaperture testing problem is then defined as an extention of the static problem. A dynamic subaperture testing numerical processor is presented which incorporates a discrete Kalman filter to exploit the sequential nature of these measurements. The processor is then simplified so that it may be used when subaperture dynamics are not known. Tuning the Kalman filter and simulating interferometer measurements of known aberrations are discussed. The results of tests using these computer simulated measurements show that the new processor is considerably more accurate than any previous method.