面向应用需求的遥感卫星载荷空间分辨率标准化研究

遥感应用需求是对地观测卫星载荷设计的出发点和落脚点,载荷的通用化、标准化、系列化是未来载荷发展的必然趋势。在对遥感应用需求分析的基础上,从应用部门关注的空间分辨率这一主要指标对遥感卫星载荷标准化进行了研究,提出了我国对地观测卫星载荷的空间分辨率设计标准,对促进遥感卫星载荷的大规模批量生产、节约设计成本具有重要意义。     

硒化铜修饰海绵烟气脱汞研究

在气相元素汞(Hg0)吸附剂的设计和生产中,如何获得性能和经济性之间的平衡是最大的挑战.本文设计了一种化学镀偶联原位硒化方法,开发了硒化铜修饰商用聚氨酯海绵(Cu2Se/PUS)吸附材料,用于燃煤烟气脱汞.Cu2Se/PUS具有优异的Hg0吸附性能,海绵的物理结构特征以及Cu2Se前驱体用量对其吸附性能均没有明显影响;Cu2Se/PUS具有良好的抗H2O和SO2干扰能力,O2对Cu2Se/PUS的Hg0吸附能力具有一定的促进作用,NO存在时会与Hg0产生竞争吸附,抑制Hg0的吸附脱除.本研究不仅为燃煤烟气Hg0的脱除提供了有效的吸附材料,也为海绵在环境修复中的应用提供了通用的功能化策略.     

实践十号返回式卫星自主安全控制策略设计

自主运行和健康管理是航天技术发展的一个重要趋势。为确保实践十号返回式卫星在飞行中的设备安全、整星能源安全和自主运行需求,从卫星系统层面进行了自主安全控制设计。首先,可以使卫星在测控弧段之外出现地面无法反应的故障时能够启动自主安全保护模式;其次,可以使卫星自主执行程序化的功能,减轻地面人员的遥控数据上注压力。实践十号卫星在轨飞行中所采取的系统级自主安全控制策略以及工程设计经验,是对航天自主运行和健康管理技术的有益探索和尝试,对后续航天器的设计有很大的借鉴意义。     

第三届高光谱成像技术及应用研讨会征文通知

正会议宗旨:以"高分五号"卫星各型载荷为主,兼顾高分专项航空系统以及其他方面支持的相关高光谱载荷为牵引开展交流;权威专家报告引领,研讨高光谱共性关键技术、数据处理和应用;注重地矿、环保、农业、林业、气象、海洋等众多领域对高光谱数据的广泛应用需求以及载荷数据的应用前景主办单位:国家自然基金委员会中国光学工程学会中国工程院信息与电子工程学部中国遥感应用协会     

航天卫星遥测数据管理与应用系统设计过程控制方法研究

过程控制技术应用于航天器地面系统开发过程已成为航天领域研究的热点问题。本文基于航天卫星遥测数据管理与应用系统的设计过程,研究了航天卫星遥测数据管理与应用系统设计过程的基本框架,分析了系统结构,以模块化化设计的理念,搭建了遥测数据管理系统的设计过程,给出了各模块系统的定义和功能结构,分析了系统模块的通信协议,最后对系统设计过程的基线确定和基线变更给出了统一的管理过程设计。     

中法海洋卫星有效载荷FDIR实现方法研究

中法海洋卫星搭载了波谱仪分系统、微波散射计分系统和数据传输分系统三种载荷，三类载荷在轨每天连续24小时不间断工作。为提高卫星在轨期间有效载荷运行的安全性，提出了有效载荷系统级故障检测隔离与恢复（FDIR, Fault detection, isolation and recovery）实现方法。有效载荷FDIR由卫星主机和载荷下位机协同完，各载荷下位机实时监测自身运行状态，发现故障时按照故障预案执行隔离操作或上报故障信息交由卫星主机处理。卫星主机还能通过平台其他分系统获得更高级别的有效载荷状态参数，综合分析后及时执行故障隔离操作。文章介绍了三类有效载荷故障监测参数选择方法、故障判断准则和故障隔离措施。各有效载荷的FDIR功能都能够独立使能/禁止，FDIR门限值、连续异常错误次数在轨均可软件调整。中法海洋卫星有效载荷的FDIR实现方法已通过地面试验验证，符合设计要求，其方法可推广至其他卫星型号。     

主被动星载大气探测载荷性能对比与分析

卫星遥感能够获取全球范围的大气环境参数,主要包括主动和被动两类探测技术。星载激光雷达作为典型的主动光学遥感载荷可以用于探测全球大气气溶胶、云、大气风场和温室气体等,并可以反演垂直廓线信息。本文概述了星载激光雷达探测技术的发展历程,较为全面地总结了星载激光雷达载荷轨道及技术参数,并与被动光学遥感载荷进行了比较,探讨了主被动星载大气探测载荷各自的优劣势和未来发展趋势。通过对比分析,为未来不同应用场景的大气探测载荷选择提供参考,有助于更好地利用卫星数据反演全球大气参数。     

基于数据模型的卫星XTCE文件设计及应用

对XTCE的内容和特点进行了介绍,给出了基于数据模型的卫星XTCE文件设计思路,详细描述了XTCE文件中空间系统,遥测遥控统一模型的设计方法,以及XTCE文件的应用方法;基于数据模型的卫星XTCE文件设计方法在实际项目中的应用表明,该方法可以快速、高效的进行XTCE文件的设计和修改,简化了卫星数据交换格式设计的流程,增强了数据交换格式的通用性和继承性,促进了各应用系统间的信息交换,提高了卫星研制的效率和可靠性。     

大型通用静力试验平台研制与应用

为了验证大型结构体的设计合理性和产品可靠性,掌握结构体负荷承载能力,给出科学评价依据和指导意见,需要科学有效的试验手段为受试对象施加载荷,获取结构体应变、位移等信息,为力学分析提供必要数据支撑。分析了试验平台的主要功能需求,研究了由荷载测控系统、应变测量系统、位移观测系统、试验管理系统和图像监控系统组成的试验平台方案,重点论述了平台的核心关键技术,通过具体应用实例和试验数据,指出了试验平台的应用领域及所能解决的实际问题,最后总结了试验平台的特点和意义。     

精密离心机测控与加速度计标校自动化系统设计

惯导加速度计在精密离心机上的标校应用试验,涉及精密离心机动态半径和静态半径的精密测量、转速的精确测控以及被校加速度计信号的正确采集与实时传输等操作,需严格控制各类测控仪器的动作时序逻辑实现精密离心机精密测控与加速度计标校应用试验的自动化操作。介绍一种精密离心机测控与加速度计标校应用试验自动化系统设计,硬件上基于LAN总线组网集成精密离心机各类测控仪器,构建分布式测控系统,并应用外部光栅编码器脉冲信号作为触发信号控制测控仪器的硬件时序同步逻辑;软件上应用共享变量技术实现各类测控参数的有序传输,针对动态波形类大数据测试信号的共享变量传输可靠性差问题,提出一种基于文件动态拷贝的网络数据传输方案,设计严格的共享变量传输逻辑机制,实现了各类测控参数正确有序采集与传输。应用试验表明,设计的精密测控与加速度标校应用试验自动化系统满足加速度计在精密离心机上的标校自动化需求,显著提高了加速度计标校应用试验效率。     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.