Research Of On-Board Data Processing Techniques For Fourier Transform Spectrometer

Fourier Transform Spectrometer is a high spectral resolution measurement instruments with high spectral efficiency, multichannel, high resolution characteristics, and is widely used in meteorology, environmental analysis or planetary atmosphere. Plane array imaging Fourier spectrometer can obtain larger area detection data by single measurement, so it’s data contain two ground dimensions, vertical dimension and time dimension. According to the characteristics of Fourier transform spectrometer, the data produced in the detector of the target radiation is very large, especially the data of the plane array imaging type interference of space borne Fourier spectrometer bring pressures for the data transfer system. So it is necessary to do on-board data processing to reduce the data size. The 3D data structure of inteferogram contains so much data that make it harder to produce in-orbit. As a high spectral instrument, the precision of spectrum obtained by the Fourier Transform Spectrometer determines the vertical distribution accuracy of the temperature, humidity and other gas molecules. So, the accuracy of spectral should be taken into consideration when data is processing.First, the development of the Fourier spectrometer on-board data processing technology is introduced with summarizing of the typical on-board data-processing scheme of some instruments. Based on the analysis of the error of the spectrum obtained by Fourier spectrometer, this paper research spectral accuracy improving method, such as spike correction, the nonlinear correction of detector, apodization, interferograms overlay, phase correction, spectral calibration, radiation calibration, and so on.According to the principle of high compression ratio and high precision spectral fidelity, dissertation compares several common on-board data processing scenarios, and then gives the on-board spectrum transform system for reducing the downloading data size. This system contains several interferogram correction algorithms like spike correction, nonlinear correction of detector, apodization, interferograms overlay, phase correction, FFT. These algorithms are optimized for the hardware system design. This on-board data processing system will not introduce additional error to the spectrum, and 32 bit Single-precision floating point data format will reserve spectra precision. After analysis and verification, this on-board data processing system can reduce the amount of data more than 40 times without losing spectra precision, and the design of multi-channel parallel processing system is scalable for larger area array or more pixels’ data processing.At last, this dissertation gives the validation of the improvement of the on-board data processing algorithm based on the experimental data produced in the calibration experiments. And then, an introduction of the data processing software, which is used for data analysis on ground is given.The results show that, this design of on-board data processing scheme and the relevant algorithm is feasible. Implementations of on-board processing algorithms can dramatically reduce the data rates, and improve the spectral accuracy. The research results of this dissertation has great reference value to the data processing technique of space borne interferometer.