Misaligned interferometer cavity optics introduce into the retrieved spectra multiplicative noise terms. Low frequency or static tilts convey a moderate impact on system performance and are manifested as amplitude distortion of the reconstructed spectrum, through a reduction of the instrument line shape function, while dynamic tilts convey a strong impact on system performance manifested as radiometric errors through a multiplicative noise term. Dynamic alignment which is an electromechanical feedback control technique of the interferometer cavity optics eliminates some extremely exacting design and fabrication requirements and provides safety margin for thermally or vibrationally induced structural distortions. Employing both coherent and incoherent radiation, several optical or electro-optical sub aperture and full aperture measurement techniques have been employed to determine the static and dynamic alignment characteristics of a customized brassboard Bomem, Inc. instrument. The unit evaluated was configured as an adaptation of their commercial DA-2 unit and employed galvanometric alignment actuators with amplitude reduction mechanical linkages.

Date Published: 21 November 1996
PDF: 29 pages
Proc. SPIE 2832, Optical Instruments for Weather Forecasting, (21 November 1996); doi: 10.1117/12.258879

Published in SPIE Proceedings Vol. 2832:
Optical Instruments for Weather Forecasting
Gary W. Kamerman, Editor(s)