摘要：Aiming at determining the thermal contact resistance of ball screws,a new analytical method combining the minimum excess principle with the MB fractal theory is proposed to estimate thermal contact resistance of ball screws considering microscopic fractal characteristics of contact *** minimum excess principle is employed for normal stress ***,the MB fractal theory is adopted for thermal contact *** effectiveness of the proposed method is validated by self-designed *** comparison between theoretical and experimental results demonstrates that thermal contact resistance of ball screws can be obtained by the proposed *** this basis,effects of fractal parameters on thermal contact resistance of ball screws are ***,effects of the axial load on thermal contact resistance of ball screws are also *** conclusion can be drawn that the thermal contact resistance decreases along with the fractal dimension D increase and it increases along with the scale parameter G increase,and thermal contact resistance of ball screws is retained almost constant along with axial load increase before the preload of the right nut turns into zero in *** application of the proposed method is also conducted and validated by the temperature measurement on a self-designed test bed.

摘要：To correctly capture spatial targets from cluttered and motive celestial background,a new Multi-Target Capture algorithm was proposed,which is a comparative difference algorithm based on the combination of centroid extraction and despun registration of efficient ***,this algorithm was applied in an image processing system based on the DSP featuring high speed and high *** procedures of image processing are as follows:first,label efficient points in the frame and extract their centroids;second,make appropriate despun registration,according to the reference rotation angles provided by Space Robot position system;third,translate and register centroid coordinates of efficient points in reference frames and get the registration points according to the principle that there are the most same centroid coordinates of efficient points when completely registered;finally,eliminate the same background points by using comparative difference *** result shows that this image processing system can meet the needs of the whole system.

摘要：为了克服不带电子快门的CCD成像探测器曝光时间无法控制的问题,提出了改变驱动时序的设计方法.在帧频确定的情况下,通过在水平读出之后增加电荷释放状态,将一帧之内多余时间段的电荷迅速排放掉,可以有效地控制CCD曝光时间,并克服CCD最小曝光时间为水平读出时间的问题.实验结果表明,大孔径静态成像光谱仪系统的抗饱和性能得到了很好的改善且此方法的非线性度为4.61%.

摘要：阵列孔径越大,空间谱分辨率越高。在借鉴传统的约束最小冗余线阵概念的基础上,从阵列输出的四阶累积量定义出发,利用四阶累积量扩展阵列孔径的功能,设计出基于四阶累积量的约束最小冗余线阵。与相同阵元数的传统约束最小冗余线阵相比,它具有大得多的有效孔径,从而在运用四阶累积量DOA估计方法时可大大增加可估计的信号数,极大地提高DOA估计分辨率。仿真结果证明了结论。

摘要：在采用基于四阶累积量的子空间法进行DOA估计时,一般要求基带信号独立,以保证信号四阶不相干, 否则估计性能将下降。该文提出一种新的四阶累积量DOA估计法,解除了对基带信号独立性的要求。该方法对每一个基带信号分配一个基带载波,基带载波相对射频载波是一个微小偏差。该文推导了在基带信号独立和相关两种情况下,信号四阶相干性与基带载波频率的关系:设计出了在基带信号相关情况下,保证信号四阶不相干的微小频偏集。仿真结果验证了设计的正确性和有效性。

摘要：研究并设计了基于光学定位法的空间瞬态光辐射信号定位系统.该系统与能量探测系统协调工作,在能量探测系统识别到目标信号后,经过定位探测、行列编码存储及DSP处理计算,最后输出闪光信号光斑的重心坐标.介绍了系统组成及各部分电路的实现方法,并给出测试结果.实验表明,系统定位准确、设计方案可行.

摘要：虚拟仪器是计算机和仪器技术深层次结合的产物,它将计算机硬件资源、仪器与测控系统硬件资源和虚拟仪器软件资源有效结合起来。基于PCI-1424图像采集卡的虚拟仪器设计实现了对图像数据采集、存储、门限处理、重心点定位的功能。

摘要：介绍了一种高速CCD相机数据存储中的FIFO缓存控制的方法。利用FPGA对高速数据存储系统中的FIFO缓存器进行控制,在QuartusⅡ开发平台上进行设计仿真,结果表明数据流和IDE硬盘之间的存储速率得到匹配,数据实时存储到硬盘中,为后期的数据处理提供了原始数据,同时也为存储系统的设计提供了参考。

摘要：多普勒差分干涉仪通过测量干涉图相位变化反演大气风速.干涉图信噪比是工程应用中影响测风干涉仪相位反演精度的核心指标之一,基于观测数据分析多普勒差分干涉仪中相位不确定度与干涉图信噪比之间的定量关系建立解析模型,对仪器设计、性能评价及风场数据应用具有重要意义.本文基于傅里叶变换光谱学噪声传递理论和多普勒差分干涉仪相位反演模型,建立干涉图信噪比与相位不确定度传递的理论模型.利用多组不同信噪比仿真及实验实测数据,将相位反演模型计算的统计结果与本文提出的理论模型分析结果进行比较验证,结果表明,多组实验数据平均残差小于0.07 mrad,两者的一致性较好,建立的模型为多普勒差分干涉仪效能评估、干涉仪设计优化提供理论依据.

摘要：测程是全站仪重要技术指标之一,本文从相位式测距仪的测程公式出发,探讨了在短基线或短距离上进行测程检测的原理和方法,为中、长程全站仪的测程检验提供了可能性。这种检验方法是在短基线或短距离上用改变反射镜有效面积进行测程实验,操作简单方便,结果可靠。利用本文研究成果可以算出任意棱镜组合所对应的测程,这样可更合理地使用棱镜,以便减少仪器幅相误差的影响,提高测程精度。