21 October 2005 The ALISEO instrument: further improvements of calibration methods and assessment of interferometer response
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In recent years the Italian Space Agency funded a feasibility study for an aerospace imaging interferometer for Earth Observation. The instrument, named ALISEO (Aerospace Leap-frog Imaging Stationary Interferometer for Earth Observation), belongs to the class of the so called "stationary interferometers," and it operates in the common path Sagnac configuration not employing any moving parts to generate phase delay. ALISEO acquires the target image as modulated by a pattern of autocorrelation functions of the energy coming from each target's location. The complete interferogram is retrieved introducing relative source-observer motion. In order to calibrate the optical-path-difference (OPD) axis of the raw interferograms, a set of measurements have been carried out illuminating a double planar diffuser system by He-Ne lasers operating at different wavelengths. Standard reflectance tiles together with diffusers doped with Holmium and Rare Earths have been used to verify the wavelength calibration of the instrument. Finally, a procedure for raw data pre-processing aimed at retrieving at-sensor radiance spectra is developed taking into account the issues of dark signal subtraction, spectral instrument response compensation, effects of vignetting, and Fourier back-transform algorithm.
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Alessandro Barducci, Alessandro Barducci, Francesco Castagnoli, Francesco Castagnoli, Paolo Marcoionni, Paolo Marcoionni, Ivan Pippi, Ivan Pippi, } "The ALISEO instrument: further improvements of calibration methods and assessment of interferometer response", Proc. SPIE 5978, Sensors, Systems, and Next-Generation Satellites IX, 59781K (21 October 2005); doi: 10.1117/12.628810; https://doi.org/10.1117/12.628810


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