  The Spectral Airglow Temperature Imager is a ground-based spectral instrument
for spatial registration of airglow emissions. The basic aim of the instrument
development is the investigation of gravity waves based on the spatial
characteristics of the temperature field at the altitude of mesopause and its
evolution in the time. The temperature retrieval is based on matching measured
and preliminary calculated synthetic spectra. Possibilities are presented for
generalization of the basic regression equation which connects the measured and
the synthetic spectra. A linear change of the background for the entire filter
transmittance interval was presumed. Numerical experiments by Monte-Karlo
simulation were conducted. The presented results show a bigger stability of the
proposed approach in comparison with the traditional one, without considering
the linear background.
