查询词典 trilateration

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。

In this thesis, we proposed a robust trilateration method to estimate Path Loss Exponent which stands for the signal attenuate rate for each reference node to target path by using two different frequency signals and the trilateration method. Then we used every PLE to calculate the corresponding distance and performed the trilateration positioning task using these distances. We also ran two simulations to evaluate our proposed method.

但另一方面，即使在同一空间中，却因为存在著许多变数而导致各个不同的路径都拥有自己的路径衰减指数，所以此篇论文我们提出先利用两个不同频率的讯号测得参考点到目标上的路径衰减指数后，再利用此数值做此路径的距离推导，最后再藉由三点定位法做出目标的定位。

In this study, we analyze the limitation of trilateration based approaches and propose a novel approach which inherits the simplicity and efficiency of trilateration, while at the same time improves the performance by identifying more localizable nodes.

本文的研究中分析了基于三边测量技术的局限性，提出了继承三边测量技术的简单性和有效性的一个新奇的方法，改方法能在提高定位性能的同时增加即可定位的节点。

RSSI-based location is a hotspot in nowadays. This paper presents RSSI-based triangle and centroid location algorithm and trilateration algorithm, and analyses the average positioning error produced by this two methods. Simulation experiments prove that triangle and centroid location algorithm can obviously improve the location accuracy compared to trilateration algorithm.

基于RSSI的定位技术是现阶段研究的热点，本文提出了基于RSSI的三角形质心定位算法和三边测量法，并对两种算法所产生的平均定位误差进行仿真分析，仿真结果表明基于RSSI的三角形质心定位算法比基于RSSI的三边测量定位算法的定位精度有较大提高。

Trilateration survey; trilateration

测量三边网的边长，以确定网中各点平面位置的技术与方法。

By definition,for targets located in a spherically stratified lower atmosphere or ionosphere,this paper derives the residual error models［Formulae (14) and (20);(24) and (27);(57) and (59),(63) and (65)］ of elevation angle refraction errors,range refraction errors and range rate refraction errors corresponding to monopulse radar and trilateration radar.

提要 本文从定义出发，推导出目标在球面分层低层大气或电离层内仰角折射误差、距离折射误差和相应于单脉冲雷达与三站雷达的距离变化率折射误差的残差模型［式(14)与(20)；(24)与(27)；(57)与(59)，(63)与(65)］。

Such trilateration is liable to rapid accumulation of azimuth error .

这样的三边测量锁的方位误差容易迅速积累。

Classically, trilateration is widely employed for testing network localizability; even in many cases it wrongly recognizes a localizable graph as non-localizable.

经典的三边测量技术广泛应用于测量网络的本地位置，甚至在很多场合错误的认为可以定位的地图为不可定位的。

The Wild GAKI Gyro Attachment is very useful, in any weather and at any time of the day or night, when it is necessary to establish a reference bearing at stations which have been fixed by arc intersection of distances, or by trilateration, with the electronic distance measuring instrument, Wild D1 50 Distomat.

Wild GAKI 陀螺附件在很多天气下，以及白天和黑夜的任何时间都是很有用的，这时，必须要建立一个支承在站台处基准，这些站台已经用距离的弧交叉，或用电子测距仪（Wild D1 50 Distomat）三边测量而固定。

But the process is called trilateration, not dilateration so don't we need a third satellite?

但这一过程被称为trilateration，不dilateration所以不用我们需要第三个卫星？

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。