共查询到20条相似文献,搜索用时 15 毫秒
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Robust wireless location over fading channels 总被引:4,自引:0,他引:4
Yousef N.R. Sayed A.H. Jalloul L.M.A. 《Vehicular Technology, IEEE Transactions on》2003,52(1):117-126
This paper develops an estimation algorithm for the time and amplitude of arrival of a known transmitted sequence over a single-path fading channel. The algorithm is optimized to enhance robustness to fast channel fading and low signal-to-noise ratio (SNR) conditions, which are common in wireless location applications. The paper also presents a noise and fading bias correction technique for amplitude of arrival estimation that improves the estimation accuracy significantly. The proposed algorithm is then applied to the case of code-division multiple-access (CDMA) wireless location finding for which the paper gives simulation results that demonstrate significant estimation accuracy improvement over known algorithms. 相似文献
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Rajika Kumarasiri Khair Alshamaileh Nghi H. Tran Vijay Devabhaktuni 《Mobile Networks and Applications》2016,21(2):286-295
This paper presents a hybrid localization algorithm for wireless sensor networks (WSNs) that simultaneously exploits received signal strength (RSS) and time difference of arrival (TDOA) measurements. The accuracy and convergence reliability of the proposed hybrid scheme are also enhanced by incorporating RSS measurements from Wi-Fi networks via cooperative communications between Wi-Fi and sensor networks. To this end, two different types of estimators based on Taylor-series (TS) expansion and maximum-likelihood (ML) estimation are first proposed to solve the set of nonlinear RSS/TDOA equations taking into account measurement errors. The corresponding Cramér-Rao lower bound (CRLB) for the established scheme is then derived and utilized as a performance measure for the two estimators. Simulation results show that the proposed hybrid positioning approach significantly outperforms the previously considered localization solutions in WSNs, thanks to the joint process of the received signals’ power and time difference of arrival. The advantages of the proposed scheme in providing high location accuracy, fast convergence, low complexity implementation, and low power consumption make it an attractive localization solution via WSNs. 相似文献
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Zoran M. Saric Dragan D. Kukolj Nikola D. Teslic 《Circuits, Systems, and Signal Processing》2010,29(5):837-856
In this paper, we consider the problem of acoustic source localization in a wireless sensor network based on different measured
signal quantities, such as the received signal strength (RSS), the angle of arrival (AOA) and the time of arrival (TOA). For
each of these quantities, an appropriate weighted least squares criterion function is developed to be used for sound source
localization. The weights of each criterion function take into account the decrease in the signal-to-noise ratio (SNR) with
distance from the source. In addition, RSS localization algorithm proposed in this paper provides improvement of the localization
accuracy for low SNR. Finally, separate criterion functions for RSS, TOA and AOA are used together to obtain minimal localization
error and maximal reliability of the acoustic source localization. Simulation analysis confirms improved performance of the
proposed localization algorithm. 相似文献
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The Cramer-Rao bound (CRB) on location estimation accuracy of two different hybrid schemes, time of arrival/received signal strength (TOA/RSS) and time difference of arrival/received signal strength (TDOA/RSS), is computed. For short-range networks, the hybrid schemes offer improved accuracy with respect to conventional TOA and TDOA schemes, particularly in the proximity of the reference devices. 相似文献
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With the widespread applicability of the Wireless Sensor Networks (WSN), localization of nodes is becoming more and more essential because of the invalidity of the massages without localization information. An algorithm called Weighted Centroid Localization (WCL) provides a simple method to localize the unknown nodes. The algorithm obtains the localization of unknown nodes by averaging the coordinates of their anchor nodes whose positions are inherently known. To improve the localization accuracy, WCL introduces the weights to attract the estimated position to approach the anchor node which has more influence, but its accuracy still has some margin for improvement. So some algorithms are presented to improve the accuracy of WCL and the modified-WCL (MWCL) algorithm is an efficient algorithm. Based on MWCL, WCL with difference of estimated distances (WCL-DED) is presented in this paper which further improves the accuracy. 相似文献
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Yunxing Ye Kaveh Pahlavan Guanqun Bao Pranay Swar Kaveh Ghaboosi 《International Journal of Wireless Information Networks》2014,21(3):208-222
This paper presents an assessment of the accuracy of cooperative localization of a wireless capsule endoscope (WCE) using radio frequency (RF) signals with particular emphasis on localization inside the small intestine. We derive the Cramer–Rao lower bound (CRLB) for cooperative location estimators using the received signal strength (RSS) or the time of arrival (TOA) of the RF signal. Our derivations are based on a three-dimension human body model, an existing model for RSS propagation from implanted organs to the body surface and a new TOA ranging error model for the effects of non-homogeneity of the human body on TOA of the RF signals. Using models for RSS and TOA errors, we first calculate the 3D CRLB bounds for cooperative localization of the WCE in three major digestive organs in the path of GI tract: the stomach, the small intestine and the large intestine. Then we analyze the performance of localization techniques on a typical path inside the small intestine. Our analysis includes the effects of the number of external sensors, the external sensor array topology, number of WCEs used in cooperation and the random variations in the transmitted power from the capsule. 相似文献
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固定单站对运动辐射源的无源定位与跟踪 总被引:4,自引:0,他引:4
利用测量获得的辐射源方位角和到达时间差信息 ,探讨了通过两种最小二乘估计实现定位的方法。本文对两种定位算法进行了比较 ,并进行了计算机模拟 ,其中第二种方法具有定位精度高、算法稳定的优点。 相似文献
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The feasibility of received signal strength (RSS) methods for locating handset calls in a complicated wireless cellular environment is demonstrated. An extensive measurement campaign conducted on the Georgia Tech campus indicates that RSS location techniques can locate handset calls within 100 m error distance to its ground truth 78% of the time for a network with a majority of indoor users. A received signal strength aggregate (RSSA) method for identifying and locating indoor handsets is also proposed. 相似文献
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Relative location estimation in wireless sensor networks 总被引:15,自引:0,他引:15
Patwari N. Hero A.O. III Perkins M. Correal N.S. O'Dea R.J. 《Signal Processing, IEEE Transactions on》2003,51(8):2137-2148
Self-configuration in wireless sensor networks is a general class of estimation problems that we study via the Cramer-Rao bound (CRB). Specifically, we consider sensor location estimation when sensors measure received signal strength (RSS) or time-of-arrival (TOA) between themselves and neighboring sensors. A small fraction of sensors in the network have a known location, whereas the remaining locations must be estimated. We derive CRBs and maximum-likelihood estimators (MLEs) under Gaussian and log-normal models for the TOA and RSS measurements, respectively. An extensive TOA and RSS measurement campaign in an indoor office area illustrates MLE performance. Finally, relative location estimation algorithms are implemented in a wireless sensor network testbed and deployed in indoor and outdoor environments. The measurements and testbed experiments demonstrate 1-m RMS location errors using TOA, and 1- to 2-m RMS location errors using RSS. 相似文献
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针对室内定位,当信号受到非视距(non-line-of-sight, NLOS)和多径传播的影响时,本文提出一种接收信号强度(Received Signal Strength, RSS)协助的Ray-tracing室内定位算法,改进已经提出的基于虚拟基站方法的信号到达时间 (Time of Arrival, TOA)和信号到达角度(Direction of Arrival, DOA)室内无线信号Ray-tracing模型,利用信号RSS测量值优化算法,实现TOA、DOA和RSS协同定位,提高室内多径及非视距环境下,无线定位的精度,降低算法复杂度,提高算法处理信号多重散射的能力并降低了对基站的依赖性适用环境更为广泛。首先通过RSS得到信号源可能存在的位置,随后利用Ray-tracing原理并使用虚拟基站,将非视距路径定位问题转化为视距路径定位问题,利用TOA和DOA对直射、透射、反射和绕射情况进行分析建模,最后使用最小二乘法对可能的位置进行筛选,得到信号源的最终位置。仿真结果表明,本算法较改进前拥有更高的定位精度。 相似文献
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Al-Jazzar S. Caffery J. Heung-Ryeol You 《Vehicular Technology, IEEE Transactions on》2007,56(2):583-593
In this paper, we address methods of mitigating one of the major issues affecting wireless location accuracy in land mobile terrestrial environments: nonline-of-sight (NLOS) propagation. In order to improve location accuracy under such conditions, we propose a novel methodology for NLOS environments based on the use of scattering models to classify propagation environments. The scattering models allow modeling of the NLOS error so that the NLOS effect can be incorporated into a location algorithm. Through the use of the scattering models, we develop three novel location techniques based on the statistics of measured ranges via moment matching, the expectation maximization algorithm, and a Bayesian algorithm. Simulation results and discussion are given to illustrate the performance in typical NLOS environments. The results show that the algorithms provide improvement over traditional location algorithms 相似文献
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This paper proposed a novel wireless location algorithm based on distance geometry(DG) constraint filtering for the time of arrival(TOA) of the signal(namely as DG-TOA).Filtering and processing of the observed data and leading to the mathematical formulas based on DG-TOA algorithm are applied to location,also play crucial rules.Simulation results show that the proposed DG-TOA algorithm can provide more valid observation data and be more precise than least square estimate(LSE) algorithm in dense,multi-route,... 相似文献
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根据时分多址(TDMA)系统的同步特征,利用TDMA运动目标准周期性信号的到达时间,提出了3种在三站时差定位系统中实现目标定位的算法.采用目标运动分析的方法,对TDMA目标位置的可观测性进行分析,提出了目标运动分析时差定位算法,利用目标航迹上多个位置的时差实现目标的定位.运用目标运动分析测距算法,提出了测距与传统时差定... 相似文献
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McGuire M. Plataniotis K.N. Venetsanopoulos A.N. 《Mobile Computing, IEEE Transactions on》2005,4(2):142-153
The location of mobile terminals in cellular networks is an important problem with applications in resource allocation, location sensitive browsing, and emergency communications. Finding cost effective location estimation techniques that are robust to non-line of sight (NLOS) propagation, quantization, and measurement noise is a key problem in this area. Quantized time difference of arrival (TDoA) and received signal strength (RSS) measurements can be made simultaneously by CDMA cellular networks at low cost. The different sources of errors for each measurement type cause RSS and TDoA measurements to contain independent information about mobile terminal location. This paper applies data fusion to combine the information of RSS and TDoA measurements to calculate a superior location estimate. Nonparametric estimation methods, that are robust to variations of measurement noise and quantization, are employed to calculate the location estimates. It is shown how the data fusion location estimators are robust, provide lower error than the estimators based on the individual measurements, and have low implementation cost. 相似文献