WAVEFRONT FOLDING INTERFEROMETER
Final rept. 1 Sep 1963-28 Feb 1965
BLOCK ENGINEERING INC CAMBRIDGE MA
Pagination or Media Count:
Results of a design study of a wavefront folding interferometer were applied to the fabrication of a prototype interferometer which was experimentally employed to make angular diameter measurements of missile re- entries. The interferometer, based on a modification to Lloyds mirror, displays the space frequency Fourier transform, including both amplitude and phase, of an incoherently illuminated object. Because the wavefront folding interferometer provides a direct positional reference, this instrument was used in the field to provide a measure of both apparent angular diameter and tracking error. The field instrument consists of a 14 cm collector telescope, a wavefront folding interferometer, and an 8 mm camera to record the fringe pattern. During the experimental program carried out on the Pacific Missile Range, the interferometer was installed on a Roti optical tracking mount. Because of the extreme pointing sensitivity of the instrument and the relatively crude tracking provided, difficulties were encountered which would be absent with more accurate tracking. Use of the folding interferometer to measure the apparent diameter of a time varying source such as a re-entry body is deemed a promising technique worthy of further investigation.
- Guided Missile Trajectories, Accuracy and Ballistics
- Optical Detection and Detectors