查询词典 estimation

Begin from the chapter three, this text expound the fact of the algorithms that the channel estimation mainly, first of all, this text has been introduced and the important function of the channel estimation algorithm of Orthogonal Frequency Division Multiplexing ,on this basis, this text Introduce the detailed introduction of the channel estimation algorithm, also essentialing structure.

从第三章开始，本文主要论述了信道估计的算法。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

Experimental results show that the performance of local parameter estimation is superior to that of global parameter estimation when there are no attacks, and the performance of local parameter estimation is worse than that of global parameter estimation when there are attacks.

通过实验得到以下结论：在无攻击条件下，局部参数估计的性能优于整体参数估计的性能；在有攻击条件下，整体估计的性能要好于局部参数估计的性能；压缩攻击会导致水印误检概率的增加，不同的攻击对模型造成的影响不同。

No additional data for frequency tracking are need, but higher estimation accuracy and low computational complexity can be obtained. Finally, a kind of optimizing joint algorithm for symbol timing, frequency synchronization and channel estimation is proposed. The false alarm probability and miss detect probability of the symbol timing are derived. We proved that the time－frequency offset domain random sequence sliding in the frequency offset direction is orthogonal with the original random sequence, and proposed a new integer frequency offset estimation algorithm. The coarse estimation methods for fractional frequency offset both in AWGN and multipath channels are proposed too.

最后，提出了一种优化的符号同步、频偏估计和信道估计的联合算法，推导了符号同步方法的虚警概率和漏检概率，给出了随机序列在时间－频率偏移域沿频率偏移方向滑动后与原序列近似正交的证明，提出了一种新的在时间－频率偏移域沿频率偏移方向进行滑动相关估计整数频偏的方法，提出了在AWGN信道和多径信道下进行小数频偏粗估计的方法，给出了小数频偏细估计的ML估计结果和利用频域PN序列取值特性的简洁的信道估计结果。

On the basis of the above, the bearing estimation property of vector sensor is discussed, including the probability density function and mathematical characteristic of bearing estimation, the influence of electrical rotation, bearing correction in the low SNR, the estimation method of SNR, the restriction of multiple targets bearing estimation, the postposition process and so on.

在此基础上，继续讨论单矢量传感器的方位估计性能问题，包括方位估计的概率密度函数及其数字特征、仿真、电子旋转产生的影响、低信噪比的方位纠偏、信噪比估计方法、多目标方位估计的局限、后置处理等内容。

Bayesian theory provides a good framework for integrating prior knowledge and maximum likelihood estimation. Bayesian based particle filtering technology has been proven to be successful for non-linear and non-Gaussian estimation problems and effective for solving tracking problems. Within methods of this class, tracking is modeled by a state-space time series estimation problem, which is solved using a sequential Monte Carlo estimation method.

视觉跟踪是实现智能监控的关键技术，作为计算机视觉研究领域的核心课题之一，融合了图像处理、模式识别、人工智能、自动控制以及计算机等若干领域的先进技术，并在军事视觉制导、视频监控、机器人视觉导航、医疗诊断以及气象分析等方面都有广泛的应用。

Firstly, the paper expatiates the essence principle of the motion estimation based block matching, introduces Full Search method and several typical motion estimation fast algorithms, and analyzes each characteristic, then to sum up the key technology for increasing the motion estimation search efficiency; Secondly, it stress introduces three motion estimation fast improved algorithms: the improved algorithm based Full Search method, it imports successive elimination algorithm、subsample and termination condition to increase search speed for enhancing the real time of Full Search.

本文首先阐述了基于块匹配法的运动估计基本原理，介绍了全搜索法和几种典型的运动估计快速算法，分析了各算法的特点，在此基础上总结了提高运动估计搜索效率的几个关键技术。接着重点介绍了本文提出的三种运动估计快速改进算法。基于全搜索的改进算法，是在全搜索的基础上尝试引入了连续排除算法、子抽样和终止条件来提高搜索速度，增强全搜索的实时性。

As a differential detection is used between the intercarrier, the proposed algorithm overcome the high sensitivity to timing error of conventional algorithm and is robust to multi-path. The effect of sample frequency offset can't be ignored in a continuous OFDM system of a large number of subcarriers. The estimation precision of the conventional algorithm is low and the realization is complex. A joint estimation of sample frequency offset and fine frequency offset based on difference operation is proposed. As averaging use a large number of samples in a maximum likelihood algorithm, the estimation precision is very high. The use of difference operation cancel the effect of carrier frequency offset, and the proposed sampling frequency estimation algorithm is robust to carrier frequency offset.

最后，本文对连续系统中的采样频率和载波频率精同步技术进行较为深入的研究，由于子载波数目大的连续OFDM传输系统中，采样频率偏差不可忽视，以往的采样频率估计方法精度低、实现复杂，因此本文提出了一种基于差分处理的采样频率偏差和精载波频率偏差联合估计算法，利用了最大似然算法进行采样频率偏差的估计，由于采用了差分处理方法，消除了载波频率偏差对采样频率偏差估计的影响，采用的最大似然算法对大量样点进行平均化处理，所以，相对以往算法，提出的联合算法估计精度高，而且采样频率偏差估计对载波频率偏差具有鲁棒性。

The estimation of additive and dominance effects through QTL analysis by onedimensional search while ignoring epistases showed similar accuracy to that by two-dimensional search by including epistases. Existence of epistases could decrease the precision for the estimation of additive and dominance effects. The estimation of genetic main effects would be biased if ignoring the interaction effects of QTL×environment . Joint analysis of multiple environments including QE interaction effects could increase the precision for the estimation of genetic main effects.

忽略上位性效应的一维搜索QTL分析对加性效应和显性效应的估计精度与包括上位性的两维搜索QTL分析对这两种效应的估计精度相差不大，上位性的存在可能会降低对这两种效应估计的精度；忽略QTL×环境互作效应会导致对遗传主效应的有偏估计，而包括QE互作效应的多环境联合分析能够提高对遗传主效应的估计精度。

The method of obtaining time delay parameters with the reverse access channel is discussed. The modified algorithms of classic correlation methods of TOA estimation are proposed. Noncoherently combining algorithm and group coherent combining algorithm are given. They decrease the computational complexity and are more suitable for implementations in practical systems. The leading edge detection algorithm is proposed to mitigate the effect of multipath in TOA estimation. Then the secondary search method is proposed, it can solve the matching issue of PN code in CDMA systems. The location algorithms based on LS are discussed; include circular trilateration with LS, hyperbolic trilateration with reference differencing, hyperbolic trilateration with sequential differencing and circular trilateration with TOA differences. The design and implementation of wireless location system based on TOA/TDOA in CDMA2000 systems are given. The location process is discussed, and the hardware and software implementation of TOA estimation are given. Finally, the wireless location system which uses TOA estimation and LS location algorithms above is tested in the real environment.

文中讨论了采用CDMA2000反向链路中的接入信道来获取时延的方法和过程；对TOA估计的传统的相关法进行了改进，提出了非相干合并相关法和分组合并相关法，减少了基于相关的时延估计算法的运算量，提高了算法的实用性，对算法进行了仿真和性能分析；采用边缘检测技术有效减少了TOA参数估计中的多径干扰，提高了时延参数估计的准确度；提出了一种TOA估计的二次搜索法，解决了多个定位测量单元同时进行TOA估计的PN码匹配问题，进一步了提高TOA估计的精度；在采用时延值的定位算法中引入了基于LS的圆周法、基于参考差的双曲线法、基于相邻差的双曲线法和基于TDOA的圆周法，讨论了各算法的应用条件，进行了算法性能的仿真分析；给出了CDMA2000系统中的TOA/TDOA的无线定位的系统方案和实现流程，并对TOA值估计算法进行了软硬件实现，还对采用TOA估计算法、LS定位算法和定位系统设计方案实现的定位系统的进行了现场定位性能测试。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。