This PDF file contains the front matter associated with SPIE Proceedings Volume 9678, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

This paper puts forward a method by realizing the internal and external radiation calibration transfer for infrared radiation characteristics quantitative measuring system. Through technological innovation and innovation application to establish a theoretical model of the corresponding radiated transfer method.

This method can be well in engineering application for technology conversion process of radiometric calibration that with relatively simple and effective calibration in the half light path radiation instead of complex difficult whole optical path radiometric calibration. At the same time, it also will provide the basis of effective support to further carry out the target radiated characteristics quantitative measurement and application for ground type infrared radiated quantitative measuring system.

In this paper, an improved Active Disturbance Rejection control (ADRC) method is proposed to enhance the tracking precision of telescope if the telescope runs in a low velocity. Low velocity telescope system usually suffers some obvious nonlinear disturbances, such as nonlinear friction and unknown external disturbance. Thereby, to ensure the tracking precision, multiple loops control structure is a common control method in telescope system, which includes current loop, velocity loop and position loop. The proposed control method is used in the velocity loop which consists of a PD controller and an Extend State Observer (ESO). The ESO is designed to estimate the disturbance involved in the telescope system. Besides, the PD controller is designed to stabilize the closed-loop system. Furthermore, this control method theoretically guarantees a prescribed tracking performance and final tracking accuracy. Finally, the experiment results show that the proposed control method has excellent performance for reducing the tracking error of low velocity.

Aerial cameras exist the image motion on the flight. The image motion has seriously affected the image quality, making the image edge blurred and gray scale loss. According to the actual application situation, when high quality and high precision are required, the image motion compensation (IMC) should be adopted. This paper designs galvanometer control system of IMC. The voice coil motor as the actuator has a simple structure, fast dynamic response and high positioning accuracy. Double-loop feedback is also used. PI arithmetic and Hall sensors are used at the current feedback. Fuzzy-PID arithmetic and optical encoder are used at the speed feedback. Compared to conventional PID control arithmetic, the simulation results show that the control system has fast response and high control accuracy.

Most of the telescope focusing systems adopt the measuring distance method to focus the quick-moving target because the imaging position of moving target is constantly changing. The focusing system calculates the focal position, controls the motor according to the distance of the target. This focusing method has a faster focusing and a better real-time performance compared to the image focusing method based on the image quality. But restricted by the external environment, the precision of instruments and technical level, Distance measuring focus system(DMFS) generally have low precision, higher dynamic adjusting delay problem. This paper mainly analyses the main error sources affecting the accuracy of DMFS, aiming at the existing defects of commonly used current speed compensation method, put forward a kind of solution path delay lag method predicted method measuring focusing system, and then simulate it, the result shows that this method can greatly improve the precision of DMFS.

In this paper, delta-M and delta-fit approximation methods for the scattering phase function in a radiative-transfer equation are reviewed. Radiance in different streams was calculated by a discrete-ordinate algorithm, and the single-variate factor method was used to investigate the influence of phase-function expansion terms on the scattering intensity. The radiance obtained by the delta-M and delta-fit methodologies was compared and discussed under different optical-depth conditions. The results show that, from the aspect of relative error, these two methods come close to standard intensity as optical depth increases, and the bias error of delta-fit is always smaller than that of delta-M for a fixed optical thickness. Delta-fit does well for all of optical depths, whereas delta-M is only good for thick optical depth. From the aspect of absolute error, delta-M is better than delta-fit under small optical depth, whereas the reverse is true when the optical depth is large.

Recently, a new kind of optical zooming technique in which no moving elements are involved has been paid much attention. The elimination of moving elements makes optical zooming suitable for applications which has exacting requirements in space, power cost and system stability. The mobile phone and the space-borne camera are two typical examples. The key to realize non-moving elements optical zooming lies in the introduction of variable curvature mirror (VCM) whose radius of curvature could be changed dynamically. When VCM is about to be used to implement optical zoom imaging, two characteristics should be ensured. First, VCM has to provide large enough saggitus variation in order to obtain a big magnification ratio. Second, after the radius of curvature has been changed, the corresponding surface figure accuracy should still be maintained superior to a threshold level to make the high quality imaging possible. In this manuscript, based on the elasticity theory, the physical model of the annular force based variable curvature mirror is established and numerically analyzed. The results demonstrate that when the annular force is applied at the half-the-aperture position, the actuation force is reduced and a smaller actuation force is required to generate the saggitus variation and thus the maintenance of surface figure accuracy becomes easier during the variation of radius of curvature. Besides that, a prototype VCM, whose diameter and thickness are 100mm and 3mm respectively, have been fabricated and the maximum saggitus variation that could be obtained approaches more than 30 wavelengths. At the same time, the degradation of surface figure accuracy is weakly correlated to the curvature radius variation. Keywords: optical zooming; variable curvature mirror; surface figure accuracy; saggitus;

The pre-slit system of Chinese SONG spectrograph is a multi-function unit. The main function is to direct the incoming light from the coudé path to the entrance slit of the spectrograph. The specific functions includes maintaining exit pupil stable, fast guiding and telescope focus corrections. The original optics of this pre-slit system were designed by Aarhus University in Denmark. We built the system and designed the software for it. This system holds a guide/slit-viewing camera, a pupil-viewing camera, two tip-tilt mirrors and its tip-tilt controllers. So it includes two sets of the fast-steering mirror systems applied to image tracking and correction. When this image tracking and correction systems is running, the real-time software algorithm will be presented and simulated simultaneously. From the images taken with camera, a closed loop signals are generated for the tip-tilt mirror to correct image motion. When the camera exposure time is 25ms,the correcting frequency of slit imge tip-tilt motion is about 30Hz. The correcting frequency of pupil imge tip-tilt motion is about 1Hz. In addition, a temperature control system surrounding the spectrograph is necessary to keep spectrograph at a constant temperature. The test results shows that the error is about ±0.005°C in 69.4 hours. The results prove that the pre-slit system of Chinese SONG spectrograph is effective and feasible.

High precision camera, designed for advanced optical system, with a wide field of vision, high resolution and fast response, has a wild range of applications. As the main payload for spacecraft, the optical remote sensor is mounted exposed to the space, which means it should have a reliable optical performance in harsh space environment during lifetime. Because of the special optical characteristic, imaging path should be accurate, and less thermal deformation for the optical parts is required in the working process, so the high precision camera has a high level requirement for temperature. High resolution space camera is generally required to own the capability of adapting to space thermal environments. The flexible satellite's change of rolling attitude affects the temperature distribution of the camera and makes a difference to optical performance. The thermal control design of space camera is presented, and analysis the temperature data in orbit to prove the thermal design correct. It is proved that the rolling attitude has more influence on outer parts and less influence on inner parts, and active thermal control can weaken the influence of rolling attitude.

The atmospheric temperature is an important meteorological parameter. The rotational Raman lidar temperature measurement system is usually used for retrieval of atmospheric temperature according to the echo signal intensity ratio. UV double grating monochromator (DGM) is a kind of spectroscopical equipment for extracting the rotational Raman's spectra. The UV DGM consists of optical fibers , focal plates , lenses and gratings. Correct parameters of the gratings, lenses, fibers are essential to the successful development of DGM. First, a suitable grating is selected according to the grating diffraction theory. Second, the diameter and focal length of lens are chosen according to ruled area and blaze angle of grating, the numerical aperture of fiber and how difficult machining is . Finally, the range of fiber core diameter is chosen according to the distance between the sixth and the twelfth spectral line on the focal plane. In order to compare the different fiber core diameter's statistical temperature error, and suppression ratio of elastic scattering light, some numerical calculations are conducted. The simulation results show that the measurement accuracy increases in the evening and approximately decreases during daytime with the increase of input fiber core diameter .As the input fiber core diameter increases, the rejection ratio is decreasing ,but they are all more than 7 orders of magnitude. It is preferable to choose input fiber with core diameter of 300um during the daytime and 600um at night. The correct parameters of grating, lens and fiber provide theoretical basis for the development of the UV DGM.

Space sensors are used in navigation sensor fields. The sun, the earth, the moon and other planets are used as frame of reference to obtain stellar position coordinates, and then to control the attitude of an aircraft. Being the “eyes” of the space sensors, Optical sensor system makes images of the infinite far stars and other celestial bodies. It directly affects measurement accuracy of the space sensor, indirectly affecting the data updating rate. Star sensor technology is the pilot for Space sensors. At present more and more attention is paid on all-day star sensor technology. By day and night measurements of the stars, the aircraft’s attitude in the inertial coordinate system can be provided. Facing the requirements of ultra-high-precision, large field of view, wide spectral range, long life and high reliability, multi-functional optical system, we integration, integration optical sensors will be future space technology trends. In the meantime, optical technologies for space-sensitive research leads to the development of ultra-precision optical processing, optical and precision test machine alignment technology. It also promotes the development of long-life optical materials and applications. We have achieved such absolute distortion better than ±1um, Space life of at least 15years of space-sensitive optical system.

There has been much recent interest in quantum technology for applications to high resolution imaging and interference measurement. Due to noise and photon loss in the transmission between the telescopes, the current optical interferometers have quite limited baselines to a few hundred meters at most, which limit the resolutions. Here we propose to use noiseless linear amplifier (NLA) to reduce optical loss in the transmission. We also show that NLA can be further improved with local squeezing operator. We envisage that our analysis on this squeezing operator assisted NLA method could help to develop higher resolution interferometers, which would have many applications in stellar observation.

The sky background infrared radiation characteristic is of great significance to target detection and extraction is of great significance. Using 3~5 micron medium wave, 8~12 microns long wave infrared measuring equipment has carried on the long-term measure to the sky background infrared radiation intensity. In this paper, the difference of the sky background infrared radiation brightness was contrast researched between the cloudless fine weather and cloudy sky of foggy weather, the influence was also analyzed of the different observation angles, the sun position and atmospheric temperature on the sky background radiation. The research results show that the infrared radiation intensity in the cloudy sky background under foggy weather is greater than in the cloudless weather clear sky, background infrared radiation intensity of long wave under the condition of same sky background radiation luminance brightness is higher than that of bilateral radiation. As the observation Angle increases, the sky background radiation intensity decreased significantly, and the decreased amplitude of sky background radiation brightness is higher under small angle than under large angle. At the same time, the factors such as solar radiation, air temperature also have a great influence on the sky background radiation. The researched result will be useful to the infrared target detection and indentification.

Mesospheric gravity waves play important roles in atmospheric circulation and variability. It is meaningful to obtain the features of the mesospheric gravity waves on a global scale, such as the distribution and the sources. However, limited by the field of view, the ground-based instrument can only access some local information. We developed a space-borne imager to observe the global gravity waves by collecting the O2 airglow with TDI (Time Delayed and Integration) method. The function of the imager was testified in our laboratory with a led screen, where the gravity waves were simulated and shown. On a satellite orbit with the altitude of 700 km and inclination of 73 degree, the imager can obtain the gravity waves with horizontal wavelength more than 10 km, even taking the effect induced by the earth rotation into account.

When the image matching method is used for motion estimation, the performance parameters like searching scope, searching speed, accuracy and robustness of the method normally are significant and need enhancement. In this paper, a novel method of block matching containing the wide range image block matching strategy and the strategy of multi-start points and parallel searching are presented. In the wide range matching strategy, the size of template block and searching block are same. And the average value of cumulative results by pixels in calculation is taken to ensure matching parameters can accurately represent the matching degree. In the strategy of multi-start points and parallel searching, the way of choosing starting points evenly is presented based on the characteristic of the block matching search, and the adaptive conditions and adaptive schedule is established based on the searching region. In the processing of iteration, the new strategy can not only adapt to the solution that lead the objective to the correct direction, but also adapt to the solution that have a little offset comparing with the objective. Therefore the multi-start points and parallel searching algorithm can be easy to keep from the trap of local minima effectively. The image processing system based on the DSP chip of TMS320C6415 is used to make the experiment for the video image stabilization. The results of experiment show that, the application of two methods can improve the range of motion estimation and reduce the searching computation.

With the increasing attention to accurate measurements of the content of atmospheric Carbon dioxide (CO₂) and its impact on climate change, satellite observation of XCO₂ (the dry air column averaged mixing ratio of CO₂) has been primarily used to monitor CO₂ source strengths because of its high spatial and temporal resolution, global coverage as well as low cost. The influence of satellite instrument index (including selection of observation bands, spectral resolution and signal to noise ratio (SNR) on XCO₂ retrieval accuracy is analyzed for typical atmospheric conditions and imaging geometry using SCIATRAN radiative transfer code. For the selection of observation bands, it is found that the maximum retrieval error appears when the right branch of 1.6μm band was used individually (~3.49ppm)，while the minimum appears when 1.6μm and 2.05μm bands were used together(~0.44 ppm). The combination of 2.05μm band with whether the left or the right branch of 1.6μm band leads to similar retrieval errors. With the decrease of spectral resolution, the retrieval error increases from 0.03ppm to 0.12ppm. While after ten percent uncertainty in Aerosol Optical Depth (AOD) was introduced, the retrieval errors increase for both high and low spectral resolution (~2.73 and 3.42ppm, respectively). For the same SNR error type (negative, positive or random), higher SNR results in better XCO₂ retrieval accuracy. Negative systematic error in SNR results in smaller retrieval error as compared to positive systematic error. And random error lies between them. SNR in the range of 300-600 can meet the requirement of the retrieval error smaller than 2ppm.

For supplying the reference to the spaced-based optical observation system design and performance analysis, the space-based observation mode for space debris is established. Considering the geometry size, the material characteristics, and the distribution region of the debris, the visual magnitude of space debris is calculated in the condition of different detection range and different phase angle. Based on the typical instance, the simulation analysis of the space debris detection ability of space-based optical observation system, which is in LEO orbit and Sub-GEO orbit respectively, is carried out. The results show that the LEO spaced-based optical observation system having an aperture of 25cm can detect the LEO 3cm space debris, which is 100km far away and has the relative velocity of 1km/s, and can also detect the GEO 1m space object, which is 37000km far away and has the relative velocity of 4km/s. The Sub-GEO spaced-based optical observation system having an aperture of 25cm can detect the GEO 1cm space debris, which is 800km far away and has the relative velocity of 15m/s.

The main difficulty in satellite retrieval of XCO₂ (the dry air column averaged mixing ratio of Carbon dioxide) from near-infrared spectra comes from the uncertainty of light path change brought by scattering of the atmospheric aerosols. The scattering effect described by different aerosol models and surface reflectances may lead to different light path change. This study aims to investigate the influence of neglecting aerosol scattering on CO₂ retrieval accuracy for different aerosol models. It is found that for rural, tropospheric and marine aerosol models, the neglecting of aerosol scattering results in underestimation of CO₂ retrievals at low surface reflectances (<0.1), but overestimation at surface reflectance over 0.1 and the retrieval errors increase with increasing surface reflectances. For urban aerosol model, the neglecting of aerosol scattering results in underestimation of CO₂ retrievals at any surface reflection, and the retrieval errors decrease with increasing surface reflectances. For typical imaging geometry, a surface reflectance of 0.1-0.3 at 1.6μm and AOD(Aerosol Optical Depth) of 0.1-0.3 at 550nm, the neglecting of aerosol scattering leads to retrieval errors of (-0.1%) - (-0.5%), 0.22%-1.92%, 0.09%-1.46% and 0.02%-0.45% for urban, marine, rural and tropospheric aerosol models respectively. XCO₂ was retrieved from GOSAT observations with in-situ measured aerosol properties during the Dunhuang2013 field experiment as input. Comparison with ground-based XCO₂ measurements shows that the retrieved XCO₂ (390.95ppm) is more consistent with the measured XCO₂ (390.737ppm) as compared to that of GOSAT L2 product (389.814ppm). Comparison of XCO₂retrieved from GOSAT measurements with in-situ measured AOD and the assumption of different aerosol models shows that the assumption of urban and marine aerosol models results in the maximum error of -1.97ppm and 1.58ppm respectively, while the rural aerosol model corresponds to the minimum error of 0.48ppm, which is mainly attributed to little difference between SSA (~0.01) of rural aerosol model and the in-situ measurements.

A new approach is presented to reduce turbulence-induced scintillation by use of a phase-locked beams array composed of linearly polarized beams with different polarization angles. The noninterference of orthogonal polarizations suggests that the beams array mentioned above can act effectively as a two-mode partially coherent beam, and the percentage of a single mode is controllable by changing the polarization angles of the beams. Numerical calculation using a multiple-phase screen method is performed to analyze the on-axis scintillation index σ_I² and mean received intensity ⟨I⟩ for the beams array propagating through weak, moderate, and strong turbulence. The effects of different polarization angles on σ_I² and ⟨I⟩ at the receiver are studied. When the turbulence is weak, numerical calculations show that both σ_I² and ⟨I⟩ are closely related to the polarization angles of the beams. And there will be a smaller scintillation index for a phase-locked beams array comprising beams with different polarization angles as compared to a uniformly polarized beams array. As the beams are phase-locked, the mean received intensity provided by them is larger than that provided by an incoherent beams array. For it is quite easy to change the polarization angles, phase-locked beams array comprising beams with different polarization angles can be a promising source in the applications that need a balance between scintillation and mean received intensity in weak turbulence conditions. When the turbulence is moderately strong, incoherent beams array is actually a better choice, because the scintillation index is smaller and the mean received intensity is as much, compared to a phase-locked beams array.

This paper describes how to design and develop an advanced Charge Coupled Device (CCD) timing generator which can obtain high precise CCD output signals. Above all, theory of the design and implementation of CCD timing generator is introduced based on Field Programmable Gate Array (FPGA) devices in detail. Secondly, it studies and analyzes the influencing factors that the waveform of CCD driving timing signals have on qualities of CCD output signals, which contain duty-cycle of HCCD clock, positive width of RST, signal-skew and delays among these signals. Then some skills are presented to improve and optimize the design in the phase of coding, compiling and placement and routing, which include code constraint, incremental placement and so on. Finally, simulation and verification of the design are performed with simulation tools, and hardware tests are carried out and experiment results are proved by oscilloscope.

The imaging spectrometer supplies spectral images in one spectral dimension and two spatial dimensions simultaneously. The Offner spectral imaging system was outstanding because of its small volume, light weight, free spectral smile and little keystone. However, the manufacture of the convex grating is a challenge and the cost is high. Here, an optical design of a compact 400-1000nm spectral imaging system using a planar grating based on a single freeform mirror was proposed. The spectrograph was similar with the Offner structure, only the grating is planar. The multi-spectra was split by the planar diffraction grating, and the collimating mirror and the focusing mirror were the same freeform surface by using it twice. The freeform surface was non-rotational symmetry. Its large degree of freedom can correct kinds of aberration, such as astigmatism, smile and keystone. The system has a compact volume as 120×100×100mm³. The entrance slit was 6mm, and the object NA(numerical aperture) was 0.12. The pixel size of the detector was 16μm×16μm, and its resolution was 375(spatial)×400(spectral). The design result showed that image quality close to the diffraction limit has been obtained. The maximums of the keystone and the smile at all working wavelengths in all fields were respectively 1.6μm and 7.5μm, which were both less than half of the pixel size. At last, the tolerance analysis considering manufacture and alignment of the system was done, the result showed that the manufacturability of the existing diamond turning machining technology can satisfy the accuracy need of the freeform mirror.

Carbon dioxide is commonly considered as the most important greenhouse gas. Ground-based remote sensing technology of acquiring CO₂ columnar concentration is needed to provide validation for spaceborne CO₂ products. A new groundbased sunphotometer prototype for remotely measuring atmospheric CO₂ is introduced in this paper, which is designed to be robust, portable, automatic and suitable for field observation. A simple quantity, Differential Absorption Index (DAI) related to CO₂ optical depth, is proposed to derive the columnar CO₂ information based on the differential absorption principle around 1.57 micron. Another sun/sky radiometer CE318, is used to provide correction parameters of aerosol extinction and water vapor absorption. A cloud screening method based on the measurement stability is developed. A systematic error assessment of the prototype and DAI is also performed. We collect two-year DAI observation from 2010 to 2012 in Beijing, analyze the DAI seasonal variation and find that the daily average DAI decreases in growing season and reaches to a minimum on August, while increases after that until January of the next year, when DAI reaches its highest peak, showing generally the seasonal cycle of CO₂. We also investigate the seasonal differences of DAI variation and attribute the tendencies of high in the morning and evening while low in the noon to photosynthesis efficiency variation of vegetation and anthropogenic emissions. Preliminary comparison between DAI and model simulated XCO₂ (Carbon Tracker 2011) is conducted, showing that DAI roughly reveals some temporal characteristics of CO₂ when using the average of multiple measurements.

Space Objects Identification(SOI) and related technology have aroused wide attention from spacefaring nations due to the increasingly severe space environment. Multiple ground-based assets have been employed to acquire statistical survey data, detect faint debris, acquire photometric and spectroscopic data. Great efforts have been made to characterize different space objects using the statistical data acquired by telescopes. Furthermore, detailed laboratory data are needed to optimize the characterization of orbital debris and satellites via material composition and potential rotation axes, which calls for a high-precision and flexible optical measurement system. A typical method of taking optical measurements of a space object(or model) is to move light source and sensors through every possible orientation around it and keep the target still. However, moving equipments to accurate orientations in the air is difficult, especially for those large precise instruments sensitive to vibrations. Here, a rotation structure of "3+1" axes, with a three-axis turntable manipulating attitudes of the target and the sensor revolving around a single axis, is utilized to emulate every possible illumination condition in space, which can also avoid the inconvenience of moving large aparatus. Firstly, the source-target-sensor orientation of a real satellite was analyzed with vectors and coordinate systems built to illustrate their spatial relationship. By bending the Reference Coordinate Frame to the Phase Angle plane, the sensor only need to revolve around a single axis while the other three degrees of freedom(DOF) are associated with the Euler’s angles of the satellite. Then according to practical engineering requirements, an integrated rotation system of four-axis structure is brought forward. Schemetic diagrams of the three-axis turntable and other equipments show an overview of the future laboratory layout. Finally, proposals on evironment arrangements, light source precautions and sensor selections are provided. Comparing to current methods, this design shows better effects on device simplication, automatic control and high-precision measurement.

A novel redundant dictionary of sparse representation is proposed to detect infrared small targets. Redundant dictionary plays an important role in sparse representation, and is the key point to guarantee the sparseness of solution. Different from traditional intensity dictionary, in this letter, the gradient information and retinal sampling pattern are used to construct the novel redundant dictionary, in which pixels near the centre have higher sampling density. It can effectively reduce the influence of background clutter around target. Consequently, it is easy to discriminate target from background according to the sparsity of the representation coefficient vector. Experimental results demonstrate that the presented method is robust and efficient.

The traditional Space Telescope has a tremendous potential shortcoming for very large aperture space telescopes. The total mass of the conventional monolithic mirror will skyrocket along with the increase of the apertures; even so much as cannot be launched to space even with the best current lightweight mirror designs. The use of a membrane diffractive optical element (DOE) can reduce the mass of large space telescopes and achieve as much as a factor of seven in mass savings per unit aperture area compared to lightweight mirrors. The primary lens of this telescope is a transmissive membrane etched with a diffraction pattern that offers a significant relaxation in the control requirements on the membrane surface figure. In 2012, the meter-scale transmissive membrane DOE was successfully developed. In 2014, the brassboard telescope of 5-meter diameter successfully demonstrates the ability to collect polychromatic high resolution imagery over a representative object using the transmissive DOE technology. All in all, the development of diffractive telescope with apertures in excess of 5 meter diameter has been put on the agenda. In this paper we first discuss the diffractive imaging system. Then some traditional deployable space optical systems are analyzed in the aspects of deployment methods and characteristics and a conceptual design for a 10m-diameter diffraction telescope is proposed. At last we talk about the key technologies for membrane diffractive telescope.

One space-based astronomy telescope will observe astronomy objects whose brightness should be lower than 23th magnitude. To ensure the telescope performance, very low system noise requirements need extreme low CCD operating temperature (lower than -65°C). Because the satellite will be launched in a low earth orbit, inevitable space external heat fluxes will result in a high radiator sink temperature (higher than -65°C). Only passive measures can’t meet the focal plane cooling specification and active cooling technologies must be utilized. Based on detailed analysis on thermal environment of the telescope and thermal characteristics of focal plane assembly (FPA), active cooling system which is based on thermo-electric cooler (TEC) and heat rejection system (HRS) which is based on flexible heat pipe and radiator have been designed. Power consumption of TECs is dependent on the heat pumped requirements and its hot side temperature. Heat rejection capability of HRS is mainly dependent on the radiator size and temperature. To compromise TEC power consumption and the radiator size requirement, thermal design of FPA must be optimized. Parasitic heat loads on the detector is minimized to reduce the heat pumped demands of TECs and its power consumption. Thermal resistance of heat rejection system is minimized to reject the heat dissipation of TECs from the hot side to the radiator efficiently. The size and surface coating of radiator are optimized to compromise heat reject ion requirements and system constraints. Based on above work, transient thermal analysis of FPA is performed. FPA prototype model has been developed and thermal vacuum/balance test has been accomplished. From the test, temperature of key parts and working parameters of TECs in extreme cases have been acquired. Test results show that CCD can be controlled below -65°C and all parts worked well during the test. All of these verified the thermal design of FPA and some lessons will be presented in this paper.

Hyperspectral imaging system for Unmanned Aerial Vehicle (UAV) is proposed under airborne remote sensing application background. By the application of Offner convex spherical grating spectral imaging system and using large area array detector push-broom imaging, hyperspectral imaging system with the indicators of 0.4μm to 1.0μm spectral range, 120 spectral bands, 5nm spectral resolution and 1m ground sampling interval (flight altitude 5km) is developed and completed. The Offner convex grating spectral imaging system is selected to achieve non-spectral line bending and colorless distortion design results. The diffraction efficiency is 15%-30% in the range of 0.4μm to 1.0μm wavelength. The system performances are tested by taking spectral and radiometric calibration methods in the laboratory. Based on monochromatic collimated light method for spectral performance parameters calibration of hyperspectral optical remote sensor, the analysis results of spectral calibration data show that the calibration test repeatability is less than 0.2 nm within one hour. The spectral scaling results show that the average spectral resolution of hyperspectral optical remote sensor is 4.94 nm, and the spatial dimension of the high-spectral optical remote sensor spectral resolution is less than 5 nm, the average of the typical spectral bandwidth is about 6 nm, the system average signal-to-noise ratio (SNR) is up to 43dB under typical operating conditions. Finally the system functionalities and performance indicators are verified by the aviation flight tests, which it’s equipped on UAV. The actual image quality is good, and the spectral position is stable.

In this paper a novel fully automated 3D reconstruction approach based on low-altitude unmanned aerial vehicle system (UAVs) images will be presented, which does not require previous camera calibration or any other external prior knowledge. Dense 3D point clouds are generated by integrating orderly feature extraction, image matching, structure from motion (SfM) and multi-view stereo (MVS) algorithms, overcoming many of the cost, time limitations of rigorous photogrammetry techniques. An image topology analysis strategy is introduced to speed up large scene reconstruction by taking advantage of the flight-control data acquired by UAV. Image topology map can significantly reduce the running time of feature matching by limiting the combination of images. A high-resolution digital surface model of the study area is produced base on UAV point clouds by constructing the triangular irregular network. Experimental results show that the proposed approach is robust and feasible for automatic 3D reconstruction of low-altitude UAV images, and has great potential for the acquisition of spatial information at large scales mapping, especially suitable for rapid response and precise modelling in disaster emergency.

A hyper spectral ground-based instrument named Atmosphere-Surface Radiation Automatic Instrument (ASRAI) has been developed for the purpose of in-situ calibration of satellites. The apparatus has both upward and downward looking views, and thus can observe both the atmosphere and land surface. The solar transmitted irradiance can be derived from the measured full spectral irradiance and diffused spectral irradiance of atmosphere within visible spectrum (0.4-1.0μm). A method similar to that of King et al. which originally intended to apply to multi-wavelength measurements, is adopted to determine absorptive gaseous columnar amount from hyper spectrum. The solar irradiance at top of atmosphere and absorption coefficients of water vapor (H₂O), ozone (O₃), oxygen (O₂) and nitrogen dioxide (NO₂) are recalculated at an instrumental spectral resolution by convolution method. Based on the gaseous characteristics of absorption, the total columnar amounts of water vapor and oxygen are first inferred from solar transmitted irradiance at strong absorption wavelength of 0.934μm and 0.763μm respectively. The total columnar amounts of ozone and nitrogen dioxide, together with aerosol optical depth, are determined by a nonlinear least distance fitting method which minimizes a χ² statistic to obtain optimal solutions. ASRAI was deployed for observation in Dunhuang site in China in August of 2014. Our results demonstrate that the algorithm is reasonable. Although the validation is preliminary, the hyper spectrum measured by ASRAI exhibits good ability to retrieve the abundance of absorptive gases and aerosols.

An attitude-varied space camera changes attitude continually when it is working, its attitude changes with large angle in short time leads to the significant change of heat flux; Moreover, the complicated inner heat sources, other payloads and the satellite platform will also bring thermal coupling effects to the space camera. According to a space camera which is located on a two dimensional rotating platform, detailed thermal design is accomplished by means of thermal isolation, thermal transmission and temperature compensation, etc. Then the ultimate simulation cases of both high temperature and low temperature are chosen considering the obscuration of the satellite platform and other payloads, and also the heat flux analysis of light entrance and radiator surface of the camera. NEVEDA and SindaG are used to establish the simulation model of the camera and the analysis is carried out. The results indicate that, under both passive and active thermal control, the temperature of optical components is 20±1°C,both their radial and axial temperature gradient are less than 0.3°C, while the temperature of the main structural components is 20±2°C, and the temperature fluctuation of the focal plane assemblies is 3.0-9.5°C The simulation shows that the thermal control system can meet the need of the mission, and the thermal design is efficient and reasonable.

The reflected Solar radiance at top of atmosphere (TOA) are, to some degree, sensitive to the vertical distribution of absorbing aerosols, especially at short wavelengths (i.e. blue and UV bands). If properly exploited, it may enable the extraction of basic information on aerosol vertical distribution. In recent years, rapid development of the advanced spectral multi-angle polarimetric satellite observation technology and aerosol inversion algorithm makes the extraction of more aerosol information possible. In this study, we perform a sensitivity analysis of the reflection function at TOA to the aerosol layer height, to explore the potential for aerosol height retrievals by using multi-angle total and polarized reflectance passive observations at short wavelength. Employing a vector doubling-adding method radiative transfer code RT3, a series of numerical experiments were conducted considering different aerosol model, optical depth (AOD), single-scattering albedo (SSA), and scale height (H), also the wavelength, solar-viewing geometry, etc. The sensitivity of both intensity and polarization signals to the aerosol layer height as well as the interacted impactions with SSA and AOD are analyzed. It’s found that the sensitivity of the atmospheric reflection function to aerosol scale height increase with aerosol loading (i.e. AOD) and aerosol absorption (i.e. SSA), and decrease with wavelength. The scalar reflectance is sensitive to aerosol absorption while the polarized reflectance is more influenced by the altitude. Then the aerosol H and SSA may be derived simultaneously assuming that the total and polarized radiances in UV bands deconvolve the relative influences of height and absorption. Aerosol layer height, Atmospheric reflection function, Sensitivity, Ultraviolet (UV) band.

Mechanical stability is a significant segment for an on-axis space telescope to assure its assembly accuracy as well as the image quality in the rigorous space environment, supporting structure between the primary mirror and the secondary mirror as a main structure of the on-axis space telescope must be designed reasonably to meet the mission requirements of the space telescope. Meanwhile, in view of the limitation of the satellite launching cost, it is necessary to reduce the weight and power compensation during the supporting structure design based on the satisfaction of telescope performance. Two types of supporting structure for a space telescope are designed, one is three-tripod structure which has three tripods located on the optical bench to support the secondary mirror assemblies and keep the distance between the primary mirror and the secondary mirror, the other is barrel supporting structure which includes a tube and a secondary mirror support with four spider struts. To compare the mechanical performance and launching cost of the two kinds of supporting structure, both structural and thermal analysis model are established. The analysis results indicates that the three-tripod support is lighter, has better mechanical performance and needs less power compensation than the barrel support.

The new progress of ground-based long-wave infrared remote sensing is presented, which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details. The prototype forms the interference fringes based on the corner-cube of spatial modulation of Michelson interferometer, using cooled long-wave infrared photovoltaic staring FPA (focal plane array) detector. The LWIR hyperspectral imaging is achieved by the process of collection, reorganization, correction, apodization, FFT etc. from data cube. Noise equivalent sensor response (NESR), which is the sensitivity index of CHIPED-1 LWIR hyperspectral imaging prototype, can reach 5.6×10^-8W/(cm^-1.sr.cm²) at single sampling. Hyperspectral imaging is used in the field of organic gas VOC infrared detection. Relative to wide band infrared imaging, it has some advantages. Such as, it has high sensitivity, the strong anti-interference ability, identify the variety, and so on.

With the diameter increasing for large aperture telescope primary mirror, the gravity caused by the increased of surface size will directly affect the quality of optical imaging, the adjustment of large aperture primary mirror will be frequent according to the requirement of observation. As the angle and the azimuth’s transformation of primary mirror influences the surface shape accuracy immediately, the rational design of the primary mirror supporting structure is of crucial importance. Now the general method is to use ANSYS APDL programming, which is inconvenient and complex to fit for the different components, the calculation require much time and the analysis is lack of efficient. Taking the diameter of 1.12 m telescope primary mirror as the research objection, the paper combine the actual design parameters of SONG telescope, respectively using ANSYS WORKBENCH to employ the primary mirror axial and lateral support model in finite element method, the optimal solution is obtained by optimization design and the change rule of mirror surface deformation under inclined condition is studied. The optimization results according with the requirements of the primary mirror comprehensive error proves that the optimization analysis method is available and applicable.

With the polynomial fitting of source function in each order of scattering calculation and the effective process of aerosol forward scattering peak, a polarized radiative transfer (RT) model based on the improved successive order of scattering (SOS) method has been developed to solve the vector radiative transfer equation. By our RT model, not only the total Stokes parameters [I, Q, U] measured by the satellite (aircraft) and ground-based sensors with linear polarization could be approximately simulated, but also the results of parameters for each scattering order event could conveniently calculated, which are very helpful to study the polarization properties for the atmospheric aerosol multiple scattering. In this study, the synchronous measured aerosol results including aerosol optical depth, complex refractive index and particle size distribution from AERONET under different air conditions, are considered as the input parameters for the successive scattering simulations. With our polarized RT model and the Mie code combined, the Stokes parameters as well as the degree of polarization for each scattering order are simulated and presented; meanwhile, the polarization (depolarization) properties of multiply scattering are preliminary analyzed and compared with different air quality (clear and pollution). Those results could provide a significant support for the further research of polarized aerosol remote sensing and inversion. Polarization properties of aerosol, successive order of scattering, vector radiative transfer equation, polynomial fitting of source function , multiply scattering

Aim to the current situation that the haze distribution detection is limited by network of point-type instruments, a three dimension scanning micro pulse lidar is researched on the basis of the Mie scattering theory of atmospheric particles. In order to strengthen detective ability of fine particles having a significant effect on human respiratory system, we choose a diode-pumped Nd:YAG solid laser with 532-nm wavelength and wind cooled technique as excited optical source to actualize lidar miniaturization. The pulse energy of 50 μJ and pulse repetitive frequency of 1 kHz are configured to ensure the eye-safety and high temporal-spatial resolution, while the lidar operates in the horizontal scanning mode. A Cassegrain telescope with clear aperture of 254 mm is utilized to collect the backscattering signal for portable multi-location observation. The lidar echo signal is filtered through an interference filter with passed bandwidth of 0.2 nm to implement all-time efficient detection. The experimental observation of atmospheric particle distribution is carried out in horizontal scanning mode. Each plane- position-indication of atmospheric particle distribution contains approximately 300 profiles in the horizontal plane within 6-min interval. Experimental results show that this lidar prototype can probe the space distribution of atmospheric particle with the range of 6 km, and that the influence of industrial production on the atmospheric particle density is 2-3 times as much as that of human activity.

In adaptive optics (AO) system, the detector noise is one of the main error sources of Shack-Hartmann wavefront sensor (SH-WFS). Based on the statistical analysis of the noise, a noise error estimation method is presented by using multiframe of the Hartmann spots pattern and the centroid displacements calculated from them. A numerical simulation system for wavefront measuring is built, and used to verify the validity of this method. It shows that the estimation error of this method could be lower than 2%, provided that the signal-noise-ratio (SNR) is sufficient for the WFS working normally. We studied the least frames of data that are required for the method when the SNR of the WFS is at different levels. It indicates that fewer frames are required as the SNR level is higher, and only 2 frames of data are required when the SNR level is high enough. For different types of detector noise, we have analyzed the influence of the accuracy of their prior information on the estimation error. It shows that the influence of the readout noise is strong, and the influence of the photon-noise, the dark-current noise and the sky-background noise is neglectable, since the WFS is usually exposed shortly. The work in this paper can be of certain significance in estimating the point spread function of AO system with the WFS measurements.

It is inevitable that tracking high-elevation object exists blind region with horizontal gimbal, need to take some control methods to improve the system for high-elevation target tracking capability and reduce the blind region. This paper compares several common tracking control methods, including compound axis control of dual detector, compound axis control of single detector, compound axis control of single detector with modified guidance, analyzes the principle of operation, advantages and disadvantages, and validates by experiments. The experimental results showed that it is stable and reliable using guide modified compound axis control of single detector when the target position information is more accurate. On the other hand, it is able to meet the needs to track target with high speed and high acceleration using improved compound axis control of single detector when the target position information is not very accurate.

Mask exchange system is an important part of the Multi-Object Broadband Imaging Echellette (MOBIE) on the Thirty Meter Telescope (TMT). To solve the problem of stiffness changing with the gravity vector of the mask exchange system in the MOBIE, the hybrid parallel mechanism design method was introduced into the whole research. By using the characteristics of high stiffness and precision of parallel structure, combined with large moving range of serial structure, a conceptual design of a hybrid parallel mask exchange system based on 3-RPS parallel mechanism was presented. According to the position requirements of the MOBIE, the SolidWorks structure model of the hybrid parallel mask exchange robot was established and the appropriate installation position without interfering with the related components and light path in the MOBIE of TMT was analyzed. Simulation results in SolidWorks suggested that 3-RPS parallel platform had good stiffness property in different gravity vector directions. Furthermore, through the research of the mechanism theory, the inverse kinematics solution of the 3-RPS parallel platform was calculated and the mathematical relationship between the attitude angle of moving platform and the angle of ball-hinges on the moving platform was established, in order to analyze the attitude adjustment ability of the hybrid parallel mask exchange robot. The proposed conceptual design has some guiding significance for the design of mask exchange system of the MOBIE on TMT.

Mask exchange system is the main part of Multi-Object Broadband Imaging Echellette (MOBIE) on the Thirty Meter Telescope (TMT). According to the conception of the TMT mask exchange system, the pre-design was introduced in the paper which was based on IRB 140 robot. The stiffness model of IRB 140 in SolidWorks was analyzed under different gravity vectors for further error compensation. In order to find the right location and path planning, the robot and the mask cassette model was imported into MOBIE model to perform different schemes simulation. And obtained the initial installation position and routing. Based on these initial parameters, IRB 140 robot was operated to simulate the path and estimate the mask exchange time. Meanwhile, MATLAB and ADAMS software were used to perform simulation analysis and optimize the route to acquire the kinematics parameters and compare with the experiment results. After simulation and experimental research mentioned in the paper, the theoretical reference was acquired which could high efficient improve the structure of the mask exchange system parameters optimization of the path and precision of the robot position.

The rotational Raman lidar is a valid tool to profile atmospheric temperature. But the fact that its proper operation generally needs a certain collocated device for calibration seriously restricts application in the meteorology and environment fields. We propose an absolute detection technique of atmospheric temperature with the rotational Raman lidar, which is based on the dependence of rotational Raman spectral envelope on temperature. To retrieve atmospheric temperature without calibration, six rotational Raman spectra of nitrogen molecule are chosen from the anti-Strokes branch. A temperature retrieval algorithm is presented and analyzed based on the least square principle. A two-cascade Raman spectroscopic filter is constructed by one first-order diffraction grating, one convex lens, one linear fiber array and 6 groups of fiber Bragg gratings. This lidar is configured with a 300-mJ pulse energy laser and a 250-mm clear aperture telescope. Simulation results show that it can extract the nitrogen molecules rotational Raman spectral lines, and that atmospheric temperature profile obtained through absolute retrieval algorithm can be up to 3.5 km with less than 0.5-K deviation within 17 minutes interval.

Automatic focusing (AF) technology plays an important role in modern astronomical telescopes. Based on the focusing requirement of BSST (Bright Star Survey Telescope) in Antarctic, an AF system is set up. In this design, functions in OpenCV is used to find stars, the algorithm of area, HFD or FWHM are used to degree the focus metric by choosing. Curve fitting method is used to find focus position as the method of camera moving. All these design are suitable for unattended small telescope.

Microorganism aggregated particle swarm, which is quite an important composition of complex media environment, can be developed as a new kind of infrared functional materials. Current researches mainly focus on the optical properties of single microorganism particle. As for the swarm, especially the microorganism aggregated particle swarm, a more accurate simulation model should be proposed to calculate its extinction effect. At the same time, certain parameters deserve to be discussed, which helps to better develop the microorganism aggregated particle swarm as a new kind of infrared functional materials. In this paper, take Aspergillus Niger spore as an example. On the one hand, a new calculation model is established. Firstly, the cluster-cluster aggregation (CCA) model is used to simulate the structure of Aspergillus Niger spore aggregated particle. Secondly, the single scattering extinction parameters for Aspergillus Niger spore aggregated particle are calculated by using the discrete dipole approximation (DDA) method. Thirdly, the transmittance of Aspergillus Niger spore aggregated particle swarm is simulated by using Monte Carlo method. On the other hand, based on the model proposed above, what influences can wavelength causes has been studied, including the spectral distribution of scattering intensity of Aspergillus Niger spore aggregated particle and the infrared spectral transmittance of the aggregated particle swarm within the range of 8～14μm incident infrared wavelengths. Numerical results indicate that the scattering intensity of Aspergillus Niger spore aggregated particle reduces with the increase of incident wavelengths at each scattering angle. Scattering energy mainly concentrates on the scattering angle between 0～40°, forward scattering has an obvious effect. In addition, the infrared transmittance of Aspergillus Niger spore aggregated particle swarm goes up with the increase of incident wavelengths. However, some turning points of the trend are associated with the absorption capacity of the swarm. When parameters of the swarm are set as follows: each Aspergillus Niger spore aggregated particle contains 40 original particles, the radius of original particle is 1.5μm, the density of aggregated particles is around 200/cm³, the measurement area is 4 meters thick, under conditions mentioned above, the infrared transmittance can be less than 10% between the incident wavelengths of 9.5～13μm. In the end, all the results provide the basis for better developing the microorganism aggregated particle swarm as a new kind of infrared functional materials and precisely choosing the effective defiladed infrared band.

The performance of The Grating Exchange System can satisfy the Thirty Meter Telescope - TMT for astronomical observation WFOS index requirements and satisfy the requirement of accuracy in the grating exchange. It is used to install in the MOBIE and a key device of MOBIE. The Wide Field Optical Spectrograph (WFOS) is one of the three first-light observing capabilities selected by the TMT Science Advisory Committee. The Multi-Object Broadband Imaging Echellette (MOBIE) instrument design concept has been developed to address the WFOS requirements as described in the TMT Science-Based Requirements Document (SRD). The Grating Exchange System uses a new type of separate movement way of three grating devices and a mirror device. Three grating devices with a mirror are able to achieve independence movement. This kind of grating exchange system can effectively solve the problem that the volume of the grating change system is too large and that the installed space of MOBIE instruments is too limit. This system adopts the good stability, high precision of rotary stage – a kind of using air bearing (Air bearing is famous for its ultra-high precision, and can meet the optical accuracy requirement) and rotation positioning feedback gauge turntable to support grating device. And with a kind of device which can carry greater weight bracket fixed on the MOBIE instrument, with two sets of servo motor control rotary stage and the mirror device respectively. And we use the control program to realize the need of exercising of the grating device and the mirror device. Using the stress strain analysis software--SolidWorks for stress and strain analysis of this structure. And then checking the structure of the rationality and feasibility. And prove that this system can realize the positioning precision under different working conditions can meet the requirements of imaging optical grating diffraction efficiency and error by the calculation and optical performance analysis.

The concepts of atmospheric refraction and atmospheric dispersion are introduced and the method of how to eliminate atmospheric dispersion. This article introduces the structure of Atmospheric Dispersion Correction , the installation position of ADC in TMT telescope and the introduction to the principle of ADC in detail. Using the finite element analysis software Ansys Workbench to analyze the rationality of the ADC structure. Static analysis The ADC structure is loaded with two tape lens, which is more 400kg in weight, as well as itself weight, will deform in x, y, z directions. Dynamic analysis The dynamic performances of ADC structure are very important for the construction of the instrument, for the environmental vibration need to be tested. That is the effect of ADC dynamic deformation on optical accuracy is crucial for imaging quality. Here three order modes of dynamic performance are presented for the references of ADC design. They are 1st order mode , 2nd order mode and 3rd order mode. Thermal deformation according to the ADC working environment temperature change, the instrument temperature would be from -5 to 9 degree. So the thermal deformation of ADC is performed in this temperature fluctuation. ADC structure FEA conclusions: The ADC tapered lens are assumed as a rigid body and the mechanical analysis results are: Static analysis, Kinetics analysis and Thermodynamic analysis. Based on the FEA results, we get the image motion information in the telescope plane. Then, we draw a conclusion that: image motions induced by current structure design are very small and meet the requirements of ADC.

Information on the vertical distribution of aerosol is important for understanding its transport characteristics as well as aerosol retrieval uncertainty. In this paper, the believable lidar ratio under clear sky condition during December 2014 is determined from ground-based lidar and sun-photometer site in Beijing. Then two methods are adopted to derive typical aerosol extinction profiles by averaging attenuated backscatter and retrieved extinction profiles respectively. The results indicate that the former vertical gradient of dispersion (standard deviation) is smaller than the latter. Moreover, the comparison of the aerosol extinction coefficient profiles shows a good consistency above 2km but significant difference below that altitude.

Sodium laser guide star is an ideal source for astronomical adaptive optics system correcting wave-front aberration caused by atmospheric turbulence. However, the cost and difficulties to manufacture a compact high quality sodium laser with power higher than 20W is not a guarantee that the laser will provide a bright enough laser guide star due to the physics of sodium atom in the atmosphere. It would be helpful if a prediction tool could provide the estimation of photon generating performance for arbitrary laser output formats, before an actual laser were designed. Based on rate equation, we developed a Monte Carlo simulation software that could be used to predict sodium laser guide star generating performance for arbitrary laser formats. In this paper, we will describe the model of our simulation, its implementation and present comparison results with field test data.