首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
基于泰勒级数展开的蜂窝TDOA定位算法   总被引:20,自引:0,他引:20  
熊瑾煜  王巍  朱中梁 《通信学报》2004,25(4):144-150
基于用户位置的应用已经成为移动数据业务的重要组成部分,使得蜂窝系统用户定位技术成为蜂窝移动通信领域的研究热点。泰勒级数展开算法因为具有精度高和顽健性强等特点而在求解非线性定位方程组中得到了广泛的应用,但它对初始值有很强的依赖性。本文使用最小二乘方法估计用户位置的初始值并使用泰勒级数展开算法确定用户坐标。通过对算法的仿真分析,结果表明本算法具有近似于基于真实值的泰勒级数展开算法的性能。  相似文献   

2.
讨论了距离无关的近似三角形内点测试(APIT)算法和基于信号到达时间差(TDOA)的泰勒级数展开算法(TSE)的优缺点,并在此基础上提出了利用两者进行混合定位。仿真的结果表明该混合定位方法能有效提高定位精度。  相似文献   

3.
熊瑾煜  王巍  朱中梁 《移动通信》2003,27(Z2):101-104
蜂窝网络用户定位是蜂窝移动通信领域研究的热点技术之一.泰勒级数展开算法在求解非线性定位方程组中得到了广泛的应用,但是它对初始值具有很强的依赖性.本文提出了一种确定泰勒级数展开初始值的最小二乘估计算法,并对算法进行了仿真分析.仿真结果表明,本算法具有近似于基于真实值的泰勒级数展开算法的性能.  相似文献   

4.
通过对泰勒级数的展开,推导了均匀角能量分布的线性阵列和圆形阵列空间相关性的泰勒近似表达式。在对空间相关性的精确表达式的基础上,通过泰勒级数的展开,得到近似的相关性的表达式,在Matlab环境下进行仿真,对泰勒级数展开的近似算法与以往的近似算法进行了比较,并将基于泰勒级数展开的近似算法与精确算法进行比较,结果表明在一定条件下,泰勒近似算法与精确算法在很大范围内有很好的一致性。通过近似算法的分析可以得出,在一定范围内,增大天线间的距离以及角能量分布标准差可以减小天线阵列的空间相关性。  相似文献   

5.
针对噪声环境下语音识别的顽健性问题,考虑到梅尔倒谱系数(MFCC, Mel-frequency cepstral coefficient)域的畸变模型高度非线性且难以处理,用分段线性插值函数代替对数函数,提出了一种新的线性畸变模型.在此基础上,导出了噪声参数估计和声学模型补偿方法,无需采用矢量泰勒级数(VTS, vector Taylor series)展开作近似处理,有效避免了模型误差的引入,增强了系统在噪声环境下的顽健性.  相似文献   

6.
赵方  马严  罗海勇  林权 《通信学报》2008,29(11):113-120
针对室内强噪声环境高精度、高顽健性定位问题,把顽健估计理论和变尺度法应用于室内定位,提出了基于顽健估计的室内节点定位算法.该算法依据余差大小,采用权值自适应调整机制,对有效测量数据进行保权处理,对可利用测量数据进行降权处理,对有害测量数据进行淘汰处理.采用具有2次收敛特性的变尺度法对目标代价函数进行最小优化,实现节点快速定位.实验表明,该算法具有良好定位精度和定位顽健性,明显优于未采用顽健估计的普通最小二乘定位算法.  相似文献   

7.
张永顺  胡庆 《信息技术》2007,31(4):65-67,70
无线自组织网络(Ad Hoc)节点的位置信息提供路由选择及节点查询等功能。节点信号的到达时间(TOA)、到达时间差(TDOA)、信号到达入射角(AOA)和信号强度的测量值已被用作移动节点相对于参考信标的定位。对Ad Hoc网络节点定位进行了研究,基于所有节点均能提供TOA/TDOA测量值的假定,提出一种仅通过部分有定位能力节点就可计算所有节点在Ad-Hoc网络中位置的方法。在此基础上,使用泰勒级数展开算法和二次WLS估计求解非线性定位方程组,以获得更高的节点定位精度。  相似文献   

8.
在3D图像处理等对运算要求高的领域,高效除法器已成为处理器内必不可少的部件。在分析除法器设计的泰勒级数展开算法基础上,提出了一种新的除法器设计算法。在满足同样精度的情况下,所实现的三级流水线的除法器.与基于泰勒级数展开算法的除法器相比,面积更小,速度更快。  相似文献   

9.
变压器局部放电超声定位中的自适应优化算法   总被引:2,自引:0,他引:2  
杨扬  王保保 《现代电子技术》2007,30(3):100-101,104
将最速下降法与牛顿法有机地结合起来。应用体元分割选取初始点,构造了无约束优化问题的一种混合迭代算法,该混合算法继承了最速下降法的全局收敛性以及牛顿法的快速收敛特点,具有较好的自适应性和较高的精确度。将其应用于电力变压器局部放电点超声波定位中,收到了很好的效果。  相似文献   

10.
基于RSSI的室内无线网络定位技术研究   总被引:1,自引:0,他引:1  
基于信号强度(RSSI)的测距是一项低成本和低复杂度的距离测量技术,被广泛应用于无线传感器网络基于距离的定位技术中。基于RSSI测距的定位技术,通过线性回归分析对参数进行优化,引入高斯滤波模型,对RSSI值进行修正,提高了测距精度。采用泰勒级数展开对位置进行迭代计算,最后在TI的ZigBee平台上进行实验验证,通过仿真和实验验证了算法的可行性和优越性。与CC2431算法相比,该算法减小了定位误差,提高了定位精度。  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

13.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

14.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

15.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

16.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

17.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

18.
It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.  相似文献   

19.
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.  相似文献   

20.
To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号