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991.
高分辨率航天光学遥感器发展新思路研究 总被引:2,自引:1,他引:1
简要介绍了高分辨率航天光学遥感器的发展,重点分析了新一代更高分辨率航天光学遥感器所采用的理论基础和发展趋势,指出了传递函数补偿(MTFC)和系统优化设计是高分辨率航天光学遥感器发展的方向之一。 相似文献
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四十年空间交会对接技术的发展 总被引:2,自引:1,他引:1
空间交会对接问世至今,已经有40年历史,在轨成功实现交会对接约300多次。文章首先从技术发展角度分析研究40年来交会对接过去和现在的技术水平、空间活动典型事例;其次讨论在轨服务技术和分析常用7种交会对接敏感器的总体性能,并作相互比较;最后讨论未来交会对接技术发展趋势。 相似文献
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为了研究盘缝带(DGB)伞在超声速条件下的阻力特性、摆动角以及伞绳载荷分布的不均匀性,在FD 12风洞中开展了盘缝带伞的阻力特性风洞试验,并通过安装柔性传感器测量了伞绳所受载荷。试验结果表明,在Ma1.50到Ma2.50来流条件下,盘缝带伞的阻力系数随着马赫数的增大先增加后减小,在Ma1.75时达到最大,为0.60,而最大摆动角则是先减小后增大,在Ma2.00时摆动角最小,为7.4°,传感器的安装对降落伞风洞试验结果影响很小。通过柔性传感器的标定和误差分析,获取了伞绳载荷数据,结果显示不同伞绳所受拉力的比值可达到1.98。且传感器数据与风洞天平的测量降落伞总载荷结果吻合,进一步验证了柔性传感器结果的正确性。 相似文献
996.
针对移动机器人基于超声波传感器的地图创建,提出了一种双重环境模型。该模型同时包涵以直线段表示的几何模型和以概率形式表示的栅格模型,结合了几何模型与栅格模型的优点。给出了该模型的建立及更新算法,并基于该模型提出了一种主动探测策略,在保证探测效率的同时减小了超声波传感器的镜面反射产生的不良影响。在室内环境下进行移动机器人实验,验证了基于双重环境模型的探测策略的有效性。 相似文献
997.
永磁双凸极电机中常见故障的机理研究 总被引:5,自引:0,他引:5
永磁双凸极电机运行时,可能会出现以下常见故障:三相绕组线或/和三相霍尔连接线的错误接线;霍尔信号自身的故障,即恒为高电平或低电平,其电平不随转子位置变化而变化。出现这些故障后,电机的电动运行将受何影响,以及如何迅速判断并排故成为重要的实际问题。文中针对12/8极转子斜槽式永磁双凸极电机,列举了电机常见的故障模式,继而分别对霍尔信号线及三相线接线故障、霍尔信号本身故障进行了详细的机理分析,得出结论,给出每一种故障出现后电机的工作情况,并通过故障模拟及工程实践验证了文中分析结论的正确性及实用性。 相似文献
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999.
Rakesh Kumar Singh Palanisamy Shanmugam 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(11):2801-2819
Despite the capability of Ocean Color Monitor aboard Oceansat-2 satellite to provide frequent, high-spatial resolution, visible and near-infrared images for scientific research on coastal zones and climate data records over the global ocean, the generation of science quality ocean color products from OCM-2 data has been hampered by serious vertical striping artifacts and poor calibration of detectors. These along-track stripes are the results of variations in the relative response of the individual detectors of the OCM-2 CCD array. The random unsystematic stripes and bandings on the scene edges affect both visual interpretation and radiometric integrity of remotely sensed data, contribute to confusion in the aerosol correction process, and multiply and propagate into higher level ocean color products generated by atmospheric correction and bio-optical algorithms. Despite a number of destriping algorithms reported in the literature, complete removal of stripes without residual effects and signal distortion in both low- and high-level products is still challenging. Here, a new operational algorithm has been developed that employs an inverted gaussian function to estimate error fraction parameters, which are uncorrelated and vary in spatial, spectral and temporal domains. The algorithm is tested on a large number of OCM-2 scenes from Arabian Sea and Bay of Bengal waters contaminated with severe stripes. The destriping effectiveness of this approach is then evaluated by means of various qualitative and quantitative analyses, and by comparison with the results of the previously reported method. Clearly, the present method is more effective in terms of removing the stripe noise while preserving the radiometric integrity of the destriped OCM-2 data. Furthermore, a preliminary time-dependent calibration of the OCM-2 sensor is performed with several match-up in-situ data to evaluate its radiometric performance for ocean color applications. OCM-2 derived water-leaving radiance products obtained after calibration show a good consistency with in-situ and MODIS-Aqua observations, with errors less than the validated uncertainties of ±5% and ±35% endorsed for the remote-sensing measurements of water-leaving radiance and retrieval of chlorophyll concentrations respectively. The calibration results show a declining trend in detector sensitivity of the OCM-2 sensor, with a maximum effect in the shortwave spectrum, which provides evidence of sensor degradation and its profound effect on the striping artifacts in the OCM-2 data products. 相似文献
1000.
Crack monitoring method based on Cu coating sensor and electrical potential technique for metal structure 总被引:1,自引:0,他引:1
Advanced crack monitoring technique is the cornerstone of aircraft structural health monitoring.To achieve real-time crack monitoring of aircraft metal structures in the course of service,a new crack monitoring method is proposed based on Cu coating sensor and electrical potential difference principle.Firstly,insulation treatment process was used to prepare a dielectric layer on structural substrate,such as an anodizing layer on 2A12-T4 aluminum alloy substrate,and then a Cu coating crack monitoring sensor was deposited on the structure fatigue critical parts by pulsed bias arc ion plating technology.Secondly,the damage consistency of the Cu coating sensor and2A12-T4 aluminum alloy substrate was investigated by static tensile experiment and fatigue test.The results show that strain values of the coating sensor and the 2A12-T4 aluminum alloy substrate measured by strain gauges are highly coincident in static tensile experiment and the sensor has excellent fatigue damage consistency with the substrate.Thirdly,the fatigue performance discrepancy between samples with the coating sensor and original samples was investigated.The result shows that there is no obvious negative influence on the fatigue performance of the 2A12-T4 aluminum alloy after preparing the Cu coating sensor on its surface.Finally,crack monitoring experiment was carried out with the Cu coating sensor.The experimental results indicate that the sensor is sensitive to crack,and crack origination and propagation can be monitored effectively through analyzing the change of electrical potential values of the coating sensor. 相似文献