In this paper, a calibration method of LVF-based spectroradiometer is summarize, including spectral calibration and radiometric calibration. The spectral calibration process as follow: first, the relationship between stepping motor’s step number and transmission wavelength is derivative by theoretical calculation, including a non-linearity correction of LVF;second, a line-to-line method was used to corrected the theoretical wavelength; Finally, the 3.39 μm and 10.69 μm laser is used for spectral calibration validation, show the sought 0.1% accuracy or better is achieved.A new sub-region multi-point calibration method is used for radiometric calibration to improving accuracy, results show the sought 1% accuracy or better is achieved.
Proc. SPIE. 8910, International Symposium on Photoelectronic Detection and Imaging 2013: Imaging Spectrometer Technologies and Applications
KEYWORDS: Digital signal processing, Detection and tracking algorithms, Calibration, Satellites, Error analysis, Fourier transforms, Field programmable gate arrays, Data processing, Space operations, Computer architecture
Historically,computationally-intensive data processing for space-borne instruments has heavily relied on groundbased processing system.But with recent advances in FPGAs such as Xilinx Virtex-4 and Virtex-5 series devices that including PowerPC processors and DSP blocks thereby provding a flexible hardware and software co-design architecture to meet computationally-intensive data processing need,So it is able to shift more processing on– board;for high data active and passive instruments,such as interferometer,Implementations of on-board processing algorithms to perform lossless data reductions can dramatically reduce the data rates,therefore relaxing the downlink data bandwidth requirements.The interferograms are performs the inverse fourier transform on-board in order to decrease the transmission rate.In [Revercomb et al.] paper show that only use the modulus of the complx spectrum will lead to big calibration errors.So the amplitude and angle of the complex spectrum is need for radiometric cablibration,but there have a big challenge for on board obtained the amplitude and angle of the complex spectrum.In this paper,we introduce the CORDIC algorithm to slove it. The CORDIC algorithm is an iterative convergence algorithm that performs a rotation iteratively using a series of specific incremental rotation angles selected so that each iteration is performed by shift and add operation,which fit for FPGA implementation,and can be parallel in a chip to fullfill different latency and throughput.Implemention results with Xilinx FPGA are summarized.