Effect of Platform Attitude Stability on Image Quality of Spatially Modulated Imaging Fourier Transform Spectrometer

Abstract

The data acquired by the spatially modulated imaging Fourier Transform spectrometer(SMIFTS) contain one dimensional spatial information, one dimensional interference information, and one dimensional pushbroom scanning spatial information. This kind of spectrometer theoretically requires that flying platform keeps uniform moving velocity and steady attitude in the imaging mode, as well as the imaging motion in each two neighboring interferograms is one array of pixels. The unsteadiness of platform would not only cause problems such as distortion, mixed pixels and lower signal-noise ratio on acquired spatial images, but also produce deviation and decadence of interferograms away from ideal ones, bringing the distortion of real spectra. The abnormal image motion model between satellite attitude and the data acquired by SMIFTS is built based on the theory that projection center of a sensor, an image point and an object on the ground are in the same line. This paper calculates the image motions between different frames, assuming that the pitch angle and yaw angle are same, And moreover, analyzes the effect of the attitude steadiness on the data quality of SMIFTS. The results show that, pitch angle bringing distortion of neighboring interferograms in alongorbit directions has most serious effect, the image gradient decrease obviouly and the discrepancy between interferogram and spectra is bigger; yaw angle bringing the relative rotation of neighboring interferograms has the less serious effect on images and spectra. To get the real spectra of the object, we should take some measures to correct it.

Theoretical Study of the Spectrum Detection and Imaging for the New Double-Sided Mirror Optical Path

“…Triangular common path interferometer imaging spectrometer [3] has a Sagnac prism, two lens optical system from the front to the detector between. There is about half of the light energy losses respectively in the second and third time through the Sagnac prism splitting surface before entering the detector.…”