视在误差

Apparent acceleration error models are established in gravity interial coordinate at launching point.

该文建立了在发射点重力惯性坐标系内的视加速度误差模型。

The result shows that the mixed boundary condition can greatly reduce the calculation area without affecting accuracy of the solution.It is followed by the higher accuracy of Dirichlet boundary condition which makes the boundary error greater when measured points is near the boundary, so we must take a sufficiently large border region.The homogeneous boundary condition has relatively large error, but the use of non-triangle poles devices makes apparent resistivity calculation error become small, because of elimination of the effect on potential difference for the infinite boundary. In inversion, in order to save computing time, homogeneous boundary conditions are often used to perform finite element forward calculation.

结果表明，混合边界条件精度最高，可大大缩小求解区域而不影响计算精度，其次是Dirichlet边界条件精度较高，但测点越靠边界误差会越大，必须取足够大的边界区域，齐次边界条件的误差比较大，但如果采用非二极装置，通过电位差计算得到的视电阻率，由于无穷远边界对电位差的影响基本消除，视电阻率计算误差与混合边界条件下的接近，在反演中，为了节省计算时间，经常使用齐次边界条件进行有限元正演。

Third, the discussion of the corresponding relationship of the real angles to the apparent real angles is performed, the asymptotic bias and MSE of real angles are given. Fourth, based on above conclusions, the analysis of two typical cases is made by numerical analysis and computer simulation: Case A when the impinging signals are divided into desired signals and interfering signals: it is shown that similar to Cyclic estimation of DOA, the smaller the separation between interfering direction and signal direction, in general, the smaller the estimation variance.

首先，研究了无穷快拍时信号数目有误的最大似然估计，引入了视在真实角度的概念；其次，导出了视在真实角度最大似然估计大样本时的分布以及渐近均方误差的解析表达式，而且还证明了：Stoica性能分析结果是现在的分析结果在信号数目准确时的特例；第三，讨论了真实角度与视在真实角度的关系，给出了真实角度的渐近偏和渐近均方误差；第四，依据前面的结果，利用数值分析和模拟实验的方法对两种典型情况做了分析： 1 在入射信号被分为干扰信号和所需信号情况下：结果表明：与CyclicDOA估计一样，干扰方向与所需信号方向靠的越近，所需信号估计的方差越小，越远离，方差越大。

In the case of the side-glance angle of beam is zero or small,an algorithm has been developed to determine the latitude and longitude of an arbitrary pixel in an air-borne strip mode SAR image without consideration of the hypsography.

在不考虑地形起伏的情况下，从机载合成孔径雷达数据采集几何关系和成像原理的角度，针对正侧视和小斜视情况提出了计算机载SAR图像像素点经纬度的一种准确而实用的方法，给出了从雷达图像上的像素点计算其经纬度的详细过程，并结合某实际机载SAR成像参数对影响定位精度的因素包括高度测量误差，航向角、俯仰角、横滚角误差和多普勒中心、多普勒调频率误差进行了详细的分析。

It describes the color characteristic of device accurately through constructing the geometric model and builds gamut mapping model in the section plane of gamut by dissecting. The improvement of image characteristic obtaining at real time satisfies the application and supports the adaptive gamut mapping. The sampling and visualization of sample set in different color space show the optic difference and give the error analysis of the color conversion between them. Based on the study of the color relation among the color spaces, the visualizing color can be created automatically with conversion formulas.

该工具在获取彩色输入／输出设备彩色特性的基础上，通过构建几何模型对设备色域进行了精确描述；利用对色域的剖分操作，构造基于剖面的色域匹配模型；通过改善图象彩色特性获取的实时性，使其能有效获取图象源的特征并满足色彩管理的应用需求，支持了自适应色域匹配；对不同色彩空间样本的采集和对比显示有效体现了色彩的视觉差别，并提供了它们之间转换的误差分析；在探究不同色彩空间的颜色对应关系的基础上，实现了可视化的真彩颜色的自动生成，使可视化颜色更加逼真。

Real stereography system was calibrated with the measuring value ofcontrol points.Measuring values were agreed very well with theoretical calculatedvalues.Further absolute errors and relative errors of the measured velocity formentioned experinent were provided according to the synthetical analyses tomeasurement results and theoretical calculated values.

并且用定位板测量参数对体视摄影系统进行了校验，理论分析和测量结果符合的相当好；在此基础上，依实际流场测量结果和理论估算相结合的综合分析，给出了速度场测量的绝对误差和相对误差。

In chapter 4, basing theories and methods of scientific visualization, and artificial neural network BP algorithm, we integrate the Visual C++, OpenGL graphics library and Excel VBA technique to develop the program of artificial neural network and to make the BP algorithm visually, this program works can be divided into four parts: Using C language to develop program about BP algorithm; Using Visual C++, develop the GUI Interface, make input parameter visually; Using OpenGL graphic technique to display the training sample point in three dimension; at last using Excel DDE technique display the error graphic tables in Excel system In chapter 5, on the view of engineering application, we establish new method of surface reconstruction basing artificial neural network, develop interface program between module and commercial CAD/CAM system, meantime deeply discuss some key problems, for example, setting up the base plane, using the API technique, cutting and editing surface boundary, and also discuss the more compliant problem: how to intersect surface, at end we finish the work of translation from our surface reconstruction module to commercial CAD/CAM system, then make reverse engineering system basing artificial neural network more useful.

第四章基于科学计算可视化理论，依据人工神经网络BP算法理论模型，综合Visual C++，OpenGL图形库以及Excel VBA等多项软件开发技术，编制了人工神经网络程序，实现了BP算法的可视化映射。具体工作分为四部分：利用C语言实现人工神经网络BP算法；利用VisualC++的GUI技术开发图形用户界面，实现参数设置可视化；利用OpenGL图形技术进行三维映射，显示学习样本及训练样本点；利用微软电子表格DDE动态数据交换技术，在Excel上动态显示学习误差曲线图。第五章从工程应用的角度出发，提出了一种新的基于人工神经网络算法的曲面裁剪重构方法，完成了曲面重建模块与通用CAD/CAM系统的接口设计工作，对其中的若干关键问题进行了深入讨论，例如基平面设定、API技术的应用、边界裁剪等问题，同时，对曲面计算中较为困难的曲面相交问题也进行的专门探讨，最终完成了曲面重建模块向CAD/CAM系统的数据传输工作，使人工神经网络逆向工程系统趋向实用。

The meshing of FG drives with misalignment, which includes shaft angle error, shaft crossing error and axial shift error, is analyzed by using the continuous tangency of pinion and FG to obtain the equations of tooth contact analysis, and visualizing contact path, and studying the effect of errors on the shift of it. A computational procedure of tooth contact is developed in this paper.

在具有安装误差的面齿轮传动的啮合分析中，建立了在有轴交角误差、轴交错误差和轴向偏移误差情况下的齿面接触轨迹所满足的方程，提出了一种求解接触点参数的策略；对齿面接触轨迹进行了可视化；分析了各类误差对齿在接触轨迹的影响。

Chirp scaling algorithm is considered more efficient and widely applicable when the bistatic SAR system is in side-look or small squint angle mode,but in large squint angle case,the errors caused by Taylor expansion are so large that the algorithm could lose its precision.In such a case,an equivalent mono-static SAR range mode which has fewer errors than Taylor expansion with large squint angle is proposed to substitute the range history of bistatic SAR.Then bistatic SAR images with large squint angles are gotten by common Nonlinear CS algorithm.The effectivity of the method is verified by Matlab simulation.

在正侧视或小斜视情况下，CS算法具有较好的聚焦性能和广泛的适用性，但在斜视角较大的情况下，该算法将散焦而不能成像，因而提出了用等效的单基地距离模型来代替双基地距离历史的方法，解决了大斜视角情况下距离模型二阶近似误差较大的问题，并结合单基地非线性CS算法，实现了在大斜视角情况下的基于GPS反射信号的双基地SAR高精度成像，最后通过Matlab仿真进行了验证。

a system of along-track mode sar based on the gps is established.by seeing the gps signal as a chirp,chirp scaling algorithm of this mode with large squint angle is investigated.chirp scaling algorithm is considered more efficient and widely applicable when the bistatic sar system is in side-look or small squint angle mode,but in large squint angle case,the errors caused by taylor expansion are so large that the algorithm could lose its precision.in such a case,an equivalent mono-static sar range mode which has fewer errors than taylor expansion with large squint angle is proposed to substitute the range history of bistatic sar.then bistatic sar images with large squint angles are gotten by common nonlinear cs algorithm.the effectivity of the method is verified by matlab simulation.

摘 要：建立了基于gps的顺轨sar系统模型，通过将gps信号等效为chirp信号，研究了在该模式下的大斜视角chirp scaling算法。在正侧视或小斜视情况下，cs算法具有较好的聚焦性能和广泛的适用性，但在斜视角较大的情况下，该算法将散焦而不能成像，因而提出了用等效的单基地距离模型来代替双基地距离历史的方法，解决了大斜视角情况下距离模型二阶近似误差较大的问题，并结合单基地非线性cs算法，实现了在大斜视角情况下的基于gps反射信号的双基地sar高精度成像，最后通过matlab仿真进行了验证。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。