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151.
针对电子干扰设备多样化的现状,以交叉眼干扰设备为例,从作战效能评估的角度进行分析,提出了交叉眼干扰设备的机上布局方案及作战效能提升的要求,并对交叉眼干扰设备在飞机上的应用进行了优化,为作战飞机电子干扰设备机上选型及布局提供技术参考。  相似文献   
152.
论文从语言内部、心理、社会三方面探讨现代汉语外来词的特点。  相似文献   
153.
In the upcoming generation of satellite sensors, hyperspectral instruments will play a significant role. This payload type is considered world-wide within different future planning.Our team has now successfully finalized the Phase B study for the advanced hyperspectral mission EnMAP (Environmental Mapping and Analysis Programme), Germans next optical satellite being scheduled for launch in 2012. GFZ in Potsdam has the scientific lead on EnMAP, Kayser-Threde in Munich is the industrial prime.The EnMAP instrument provides over 240 continuous spectral bands in the wavelength range between 420 and 2450 nm with a ground resolution of 30 m×30 m. Thus, the broad science and application community can draw from an extensive and highly resolved pool of information supporting the modeling and optimization process on their results. The performance of the hyperspectral instrument allows for a detailed monitoring, characterization and parameter extraction of rock/soil targets, vegetation, and inland and coastal waters on a global scale supporting a wide variety of applications in agriculture, forestry, water management and geology. The operation of an airborne system (ARES) as an element in the HGF hyperspectral network and the ongoing evolution concerning data handling and extraction procedures, will support the later inclusion process of EnMAP into the growing scientist and user communities.  相似文献   
154.
主要介绍了在高度编码器的实现过程中,为了将其接收到的ARINC429数据转换为接收设备所能够接收的格雷码信号,通过高度编码器结合HS-3282集成电路芯片和C51单片机,实现了数据的转换。  相似文献   
155.
针对基于TMS320F2812DSP参数装订过程中出现的问题,通过分析TMS320F2812DSP的存储器映像、片内Flash存储器的特点,以PC机和TMS320F2812DSP控制系统通过422串口通讯的过程为例,提出了一种在伺服电机控制过程中实现在线参数装订的设计方法。通过实例验证,该设计实现了参数的快速装订,提高了工作效率。  相似文献   
156.
This paper describes the development and validation of a transportable active transponder designed for the image calibration of Korea Multi-Purpose Satellite-5 (KOMPSAT-5) with a synthetic aperture radar (SAR). Ground targets are essential in SAR image calibration. The environment for the deployment of ground targets for SAR image calibration should provide uniformity and minimum interference. The Amazon or deserts are regarded as desirable environments. However, such environments for SAR image calibration are difficult to find in Korea. Thus, it will be advantageous to have an active transponder whose performance will not be severely limited by the absence of such uniform environment. We have therefore developed an active transponder which has an adjustable internal delay and into which the orbit data of an arbitrary satellite can be loaded. The stored obit data with the aid of an internal global positioning system (GPS) receiver and gyroscope enables the active transponder to point to a selected satellite. In addition, a virtual deployment of the active transponder is possible due to its adjustable internal delay. Thus, the developed active transponder can be deployed at any place without environmental constraint. The performance of the developed active transponder is validated using the satellite TerraSAR-X, which is already in operation. The test results show that the active transponder is successfully compliant with the requirements for KOMPSAT-5 image calibration.  相似文献   
157.
HF sky-wave backscatter sounding system is capable of measuring the large-scale, two-dimensional (2-D) distributions of ionospheric electron density. The leading edge (LE) of a backscatter ionogram (BSI) is widely used for ionospheric inversion since it is hardly affected by any factors other than ionospheric electron density. Traditional BSI inversion methods have failed to distinguish LEs associated with different ionospheric layers, and simply utilize the minimum group path of each operating frequency, which generally corresponds to the LE associated with the F2 layer. Consequently, while the inversion results can provide accurate profiles of the F region below the F2 peak, the diagnostics may not be so effective for other ionospheric layers. In order to resolve this issue, we present a new BSI inversion method using LEs associated with different layers, which can further improve the accuracy of electron density distribution, especially the profile of the ionospheric layers below the F2 region. The efficiency of the algorithm is evaluated by computing the mean and the standard deviation of the differences between inverted parameter values and true values obtained from both vertical and oblique incidence sounding. Test results clearly manifest that the method we have developed outputs more accurate electron density profiles due to improvements to acquire the profiles of the layers below the F2 region. Our study can further improve the current BSI inversion methods on the reconstruction of 2-D electron density distribution in a vertical plane aligned with the direction of sounding.  相似文献   
158.
考虑螺栓与钉孔的接触及材料的弹塑性,应用非线性有限元法模拟分析带裂纹钉孔的应力分布,得出钉传载荷作用下钉孔裂纹应力场的分布。  相似文献   
159.
Orbit manoeuvre of low Earth orbiting (LEO) debris using ground-based lasers has been proposed as a cost-effective means to avoid debris collisions. This requires the orbit of the debris object to be determined and predicted accurately so that the laser beam can be locked on the debris without the loss of valuable laser operation time. This paper presents the method and results of a short-term accurate LEO (<900 km in altitude) debris orbit prediction study using sparse laser ranging data collected by the EOS Space Debris Tracking System (SDTS). A main development is the estimation of the ballistic coefficients of the LEO objects from their archived long-term two line elements (TLE). When an object is laser tracked for two passes over about 24 h, orbit prediction (OP) accuracy of 10–20 arc seconds for the next 24–48 h can be achieved – the accuracy required for laser debris manoeuvre. The improvements in debris OP accuracy are significant in other applications such as debris conjunction analyses and the realisation of daytime debris laser tracking.  相似文献   
160.
是以国家863重大能源专项“微型燃机控制系统”的研发为工作基础,总结了项目开发过程中系统通讯问题而完成的。微型燃机控制系统由7个模块组成,每个模块由一片TMS320LF2407型DSP控制,各模块之间采用CAN总线进行通讯。给出了CAN总线通讯的软硬件设计,并详细介绍了多片DSP之间通讯的实验过程,给出实验结果,制定出通讯协议。  相似文献   
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