Design and Implementation of Ultra-Low Speed Optical Path Scanning Control System for Space-Borne Fourier Spectrometer

In order to achieve high signal-to-noise ratio spectral detection performance, the time modulation Fourier transform spectrometer based on Michelson interferometer theory has a strict requirement on velocity stability of the swing arm in scanning movement. In this paper, an ultra-low speed optical path scanning control system with the angular velocity of 0.1311°/s is designed and implemented for a space-borne Fourier spectrometer system. The control algorithm is given, and the nonlinear parts which have a great effect on velocity stability in the feedback path are explained. The simulation of control system by different velocity measurement methods is introduced with detailed descriptions of simulation steps, parameter settings and simulation results. An improved low-delay T-method for velocity measurement is proposed and applied to the control system in the space-borne Fourier spectrometer prototype. The experimental results for this improved method is obtained from the prototype and the velocity stability reaches 99% above, which meets the requirement of spectrometer system for high signal-to-noise ratio spectral detection performance.