Abstract

This paper introduces an intensity simulation for the Fourier transform infrared spectrometer whose core element is the Michelson interferometer to provide support for the on-orbit monitoring of the instrument and to improve the data processing and application of the Fourier transform spectrometer. The Geostationary Interferometric Infrared Imager (GIIRS) aboard on Fengyun-4B (FY-4B) satellite, which will be launched in 2020, aims to provide hyperspectral infrared observations. An intensity simulation of the Michelson interferometer based on the GIIRS’s instrument parameters is systematically analyzed in this paper. Off-axis effects and non-linearity response are two important factors to be considered in this simulation. Off-axis effects mainly cause the wavenumber shift to induce a large brightness temperature error compared with the input spectrum, and the non-linearity response reduces the energy received by the detector. Then, off-axis effects and a non-linearity response are added to the input spectrum successively to obtain the final spectrum. Off-axis correction and non-linearity correction are also developed to give a full simulation process. Comparing the corrected spectrum with the input spectrum, we can see that the brightness temperature errors have a magnitude of 10−3 K, and this fully proves the reliability and rationality of the whole simulation process.

Highlights

  • The Michelson interferometer is a precision optical instrument designed and manufactured by American physicist Michelson and Morey in 1883, with the aim of studying the “ether” drift.It is a split-amplitude interferometer, which generates interference by splitting the amplitude of the input light into two parts, and by adjusting the distance of the moving mirror from the beam splitter, changes in interference fringes can be observed [1,2]

  • Rayleigh found that the interferogram generated from the Michelson interferometer has a mathematical relationship with the spectrum of the light source, and he obtained the spectrum using the Fourier transform [3]

  • This paper demonstrates an interference intensity simulation of the Michelson interferometer following the FY-4B GIIRS’s instrument parameters, including off-axis effects and the nonlinearity response

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Summary

Introduction

Spectrometer is taken as an example to show the results of Following orderthe of Fourier addingtransform the off-axis effect, non-linear response, non-linearity correction the ILS and correction, intensity computation. Theused space-borne interferometer in geostationary and off-axis the changesFY-4B in BTGIIRS errorisare to illustrate the reliability of the full orbit, which we use to measure the three-dimensional atmospheric structure, whose core simulation process. In this simulation, the input spectral bands are medium wave ), andFigure the Set placement of of detectors inprocess

The Principle of the Michelson Interferometer
Introduction of the Simulation
Radiative
Computation of the ILS
Geometry
Intensity
Nonlinearity Response of the Detector
ILS for Various Positions of Detectors
Intensity with
10. Analysis
Analysis of the Nonlinearity Response
Intensity Simulation with Off-Axis Effects and the Non-Linearity Response
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