With continuous development, the hyperspectral imaging has become a hot topic in the field of remote sensing, since its enormous advantage in obtaining the material composition of atmosphere, land resources, battlefield environment and marine resources while observing the Earth in space. However, some challenges have hindered the application of space-based hyperspectral imaging system. To fulfill the requirements of the spectral imager especially for space use, the lightweight and stable structure is especially important. Here the implementation of a Large Aperture Hyperspectral Imaging Optical System is presented. The optical system achieves hyperspectral imaging from ultraviolet to infrared spectral bands. The different spectral bands share a large common aperture of Ø1.8m. A lightweight primary mirror is designed and supported by bipod structure. To keep the large distance between the primary mirror and second mirror, a Lightweight and high-strength truss has been applied. A hierarchical structure is adopt as the main structure of the whole system. With the diffraction gratings and optical slits, the image information of different spectral bands are detected by the different lines of pixels in a focal plane of planar array. By the creative works of the optical and mechanical design, a hyperspectral imaging optical system is implemented and shows the extensive application potential in space remote sensing.
High performance infrared lens used in aerospace optical remote sensing systems have great benefit in resource exploration, pollution monitoring etc. However the high technical threshold of manufacture, the production and launch cost due to the heavy infrared optical materials, and the long period of alignment have restricted its use especially for civil and commercial aerospace. Here we present a realization of aerospace infrared lens for mass production. An unique opto-mechanical structure design has been implemented in order to meet the requirements of the mass production of space infrared lens. Some high effective, low cost processing technology are used both for optical and mechanical parts. The produced lenses have the biggest diameter of 300mm and the best RMS of λ/50(λ=632.8nm). A smart alignment based on an online device with lens alignment and image quality measurement reduces the period from 30 days to 7 days. With the well assembled infrared lens, the space camera has a system wavefront of 0.1λRMS (λ=3.39μm) and the MTF of 0.38(@25lp/mm).
Discrete support technology has been widely used in the mirror support of space optical remote sensor due to its high lightweight and good environmental adaptability. In this paper, a six point discrete structure is designed to meet the high force and thermal stability requirements of a lightweight mirror with a diameter of Φ550mm in a high-resolution space camera. Through the analysis of the mirror stiffness and the adaptability under various environmental effects such as gravity, temperature, shrinkage of glue spots and overload, the rationality of the structural design is verified, and the indicators meet the application requirements of space optical remote sensor.
This paper analyzes the optical characteristics of the filter as a plane-parallel plate glass, and discusses the influence of the filter on the optimal focal plane position of the system according to the nature of the backward focus position, and proposes a large field of view space remote sensor sub-field of view The fixed focus scheme; through analyzing the working principle of the splicing instrument, the influence of the filter on the distance measurement of the splicing instrument is discussed, and the precautions of the mixed splicing of a variety of different filter detectors are studied, and a variety of detector confocal surfaces are obtained The calculation formula of splicing optical path difference, a variety of detectors hybrid splicing confocal surface scheme is proposed.
With the increasing function density of space optical remote sensor, the integration of visible and infrared space camera has become an important development direction. As the main vibration, the micro-vibration of refrigerator is the key to affect the imaging quality of optical remote sensor. In this paper, three commonly used micro-vibration test methods are compared, and the fixed-support force test method is used to test and analyze the micro-vibration performance of a pulse tube refrigerator under different power and use state. It is pointed out that the strategy of using compressor vibration isolation to mount satellite is more suitable for the Visible and infrared integrated space camera.
In order to realize MTF detection without collimator, first establish an auto collimate detect system, analysis its principles and requirements. Then, simplify its optical path , give the formula of reflexed direction angle of target fringes, give the formula of its effect on MTF. Compare the coaxial system and off-axial system: target deflection caused the test MTF to drop to 87.9% of the actual MTF. Give the design method of autocollimation target, using this method, for an off-axis camera, the MTF test error due to target deflection can be reduced from 12.1% to a negligible level. Finally, discusses the splicing of detector and target, analysis the effect of filter on focal plane, propose the confocal design and splicing.
Space infrared sensor must be assembled on a small satellite platform, so its whole mass and structure dimensions are
strictly restricted by the satellite platform. The mechanical structure must be compacted, light, handy and reliable. Task
of space infrared sensor structure system is to integrate each parts of system and provide a stable and reliable work
platform for the whole body. The transfer functions of flexible object and base are analyzed by using mechanical
impedance method and compared with stiffness models. It indicates that space infrared sensor must be considered the
flexible body influence for transfer function on some certain conditions. Using second order Krylov method expresses
multi-DOF flexible substructure, which combines with modal synthesis method to model and analyze two substructures
connecting with springs and dampers. Compared with direct FEM arithmetic, it can improve the calculation efficiency
and handle variable-rate stiffness and damping model or complex stiffness model of flexible connection, which is cannot
do for common commercial FEM software.
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