斜视步进画幅遥感相机像移补偿方法研究

提出一种通过扫描镜两轴旋转与像面旋转机构,配合使用实现斜视画幅相机像移补偿方法.首先,在扫描镜处建立飞机牵连铅锤坐标系、机体坐标系、航迹坐标系、扫描镜补偿坐标系、提取相机几何模型,假定机体坐标系与镜头光学系统物方主点重合.为求得两轴补偿角速度,必须经过坐标变换解算出目标在扫描镜补偿坐标系下的速度和视轴长度;为计算像面旋转机构的位置,必须计算目标在机体坐标系下像面上的像移速度.由于获得的姿态角信息来自飞机惯导系统,受实际条件制约,须对上述理想算式进行简化,以便工程应用,最终给出了简化后的补偿公式.     

弹载星敏感器像移模型及其仿真分析

星敏感器像移模型是星图运动补偿算法的关键技术,也是动态星模拟算法中的重要组成,它为高分辨率星敏感器的全链路运动模糊的建模仿真提供支撑。首先,借助正态分布的静态星像能量模型,引入星像移速度,得到匀速运动星像的能量分布函数。其次,为了获取星像移速度,研究了两种解算方法:（1） 基于坐标系转换的星像移模型;（2） 基于星光矢量旋转的像移几何模型。最后,建立仿真环境,通过调整积分时间、三个姿态角变化率、发射时间、地点、观星时弹体姿态角等输入参数,可以获取弹载星敏感器在轨运动时观测星像的重要仿真数据:如导航星信息,像移大小、方向,灰度分布,信噪比等。这对星图运动补偿算法的研究和评价都显得十分必要。     

航空遥感器扫描反射镜与窗口尺寸的计算与分析

航空遥感器扫描反射镜按照给定的速度旋转,补偿飞行器运动以及姿态变化引起的像移,为此需要确定补偿后反射镜的大小、航空遥感器窗口的位置与大小.运用光学反射矢量的基本理论,给出扫描反射镜的反作用矩阵,补偿后光线矢量间的关系;通过推导建立扫描反射镜转轴位置与反射镜大小、窗口位置及大小的理论计算公式;以实际遥感器的的工作参数为条...     

姿态变化对航空推扫式成像的影响分析

航空推扫成像时,由载机的姿态变化产生的像移是影响光学成像质量的主要因素之一,可由稳定平台进行补偿。基于某机载成像光谱仪系统,首先利用齐次坐标变换法建立像移速度矢量的精确计算模型,分析了成像质量对飞行姿态精度的要求,从而选定稳定平台参数。接着,分析了姿态补偿残差对成像质量的影响,得出引起的相对像移速度偏差仅为10-1,为后续光谱定标和几何校正提供了参考。再次,研究了给定成像要求的飞行参数指标的分配问题,进行了像移速度误差分析。最后,开展了飞行成像试验。结果表明所选的PAV30稳定平台能够确保成像期间的姿态稳定,验证了上述分析正确合理。所提出的方法简单,易于实现,具有一定的工程应用价值。     

对地观测相机像移速度矢量建模

基于矢量关系运算和不同坐标系之间的转换, 推导了对地观测相机的像移速度矢量模型。该模型适用于机载和星载两种平台, 且在模型中考虑了地球扁率、姿态指向精度、姿态角速度等因素对像移的影响。对所提出的像移速度矢量计算模型进行了仿真分析。仿真结果表明, 机载成像时, 像移速度随载体飞行速度的增加而增加, 随飞行高度的增加而减少; 地球扁率因素对星载相机像移有重要影响, 在近极处引起的误差可达4.60%; 姿态参数对星载相机像移的影响大于机载相机。     

面阵CCD航测相机像移补偿技术研究

航空相机在拍照瞬间由于飞机的飞行运动和姿态变化而产生像移,要提高照相分辨率必须通过像移补偿来实现。采用在相机与飞机间增设三轴稳定平台的机械式像移补偿法来补偿姿态像移和前向像移,三轴稳定平台的三轴按照与飞机姿态变化角速率相等、方向相反进行旋转补偿姿态像移,三轴稳定平台的俯仰轴以飞行方向反方向、角速率等于速高比旋转补偿前向像移,并采用坐标变换法计算像移补偿后的残差,通过分析面阵CCD相机像面各点在进行像移补偿后的像移残差均小于1/3像元,符合成像要求。     

星载遥感相机像移分析

随着航天遥感技术的不断发展,遥感相机对地分辨率不断提高。在空间遥感成像过程中,由于成像载体与地面目标之间存在相对运动,导致目标图像在成像介质上产生像移,使遥感图像模糊不清,所以像移补偿成为提高成像质量和相机分辨率不可缺少的环节。通过建立计算遥感像移的数学模型,对各种因素产生的像移影响进行定量分析。结果表明:对星载遥感相机进行像移补偿时,可以忽略由于卫星姿态改变等随机因素产生的像移,而主要补偿因卫星沿轨道运动和地球自转造成的像移。最后,通过对实例的仿真验算,提出了一套针对星载遥感相机的机械式像移补偿方案。     

星载TDICCD 相机方位扫描像移模型研究

在应用坐标系变换方法实现星载TDICDD 相机星下点扫描像移模型的基础上,将45旋转扫描反射镜（以下简称45镜）用于TDICCD 相机成像以扩大扫描视场。首先深入分析了45镜的成像特性及K 镜消像旋的原理,并利用Matlab 对K 镜消像旋效果进行仿真,验证了加入K 镜的合理性。然后利用45镜及K 镜对光矢量的转换矩阵,建立了TDICCD 相机方位扫描时的像移模型,为后续像移分析提供理论依据。     

框幅式航测相机中像移量对直接地理定位精度影响的研究

在航空摄影测量中,载机前向飞行和姿态旋转引起的像移模糊会为同名像点的量测引入误差,使共线方程偏离共线的条件,进而导致直接地理定位的精度下降。为定量分析像移对物点直接定位的影响,从摄影测量的共线方程出发,在充分考虑前向飞行和姿态旋转的条件下,建立了框幅式相机中CCD靶面各点像移量的数学模型。根据该模型计算出像移轨迹中的质心坐标和其对应的曝光时标,并以质心确定同名像点坐标,以中心曝光时间作为曝光时标以获得对应的外方位元素。仿真结果表明,在理想条件下,以上述方法进行双像前方交会的物方定位误差最大为0.12 mm,有效降低了像移对直接地理定位的影响。文中为分析框幅式航测相机中像移量对位置精度的影响和曝光时标的确定提供了理论依据。     

面阵CCD航测相机前向像移补偿技术研究

航空相机在拍照瞬间由于飞机的飞行运动和姿态变化而产生像移,要提高照相分辨率必须进行像移补偿。文章介绍了两种面阵CCD航测相机前向像移补方法,即旋转俯仰轴补偿法和面阵CCD TDI功能补偿法,计算了两种方法的像移残差及误差精度,给出了旋转俯仰轴方法的适用范围,对比了两种方法的优劣,通过实验室拍摄验证了方法的有效性。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its