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5th International Conference on Wireless Communications, Networking and Mobile Computing

作者： Zhu, Feng-juan Wei, Zong-heng Hu, Bin-jie Chen, Jian-guang Guo, Zi-min South China Univ Technol Sch Elect & Informat Engn Guangzhou Guangdong Peoples R China Radio Monitoring Ctr Guangdong Prov Guangzhou Guangdong Peoples R China

ISBN: (纸本)9781424436927

RFID technology is gaining much attention for indoor localization because of its advantages such as non-contact and non-line-of-sight nature. In this paper, we study two typical approaches using active RFID for indoor location sensing: LANDMARC and VIRE, and point out that the latter approach with a fixed threshold of Received Signal Strength Indication (RSSI) difference which determines the elimination of unlikely positions does not work well in complicated indoor environments with severe radio signal multi-path. Analysis of two important factors in VIRE directs us some improvements for adaptation to enhance the accuracy of indoor localization.

关键词： Indoor location positioning algorithm RFID

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Implementation of Indoor positioning System based on Location Fingerprinting in Wireless Networks

Implementation of Indoor Positioning System based on Locatio...

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4th International Conference on Wireless Communications, Networking and Mobile Computing

作者： Zhao, Yongxiang Zhou, Huaibei Li, Meifang Kong, Ruoshan Wuhan Univ State Key Lab Software Engn Wuhan 430072 Peoples R China Wuhan Univ Sch Management Wuhan 430070 Peoples R China Wuhan Univ Int Sch Software Wuhan 430072 Peoples R China

ISBN: (纸本)9781424421077

With the rapid development of wireless networks, location aware services are becoming more and more attractive especially in indoor areas. To provide location aware services, obtaining the position of a user accurately is vital and using existing communications infrastructure is preferred for cost reasons. In recent years, location fingerprinting schemes are still the most promising because of technical restrictions. In this paper, we discussed the implementation of indoor positioning system firstly. Then we presented experimental testbed methodology, and data collection and discussed the experimental results and analysis. Finally, we summarized the paper and gave possible future directions for research on wireless positioning systems for indoor environments.

关键词： Indoor positioning location fingerprinting positioning algorithm wireless localization

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RFID Tags: positioning Principles and Localization Techniques

RFID Tags: Positioning Principles and Localization Technique...

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1st IFIP Wireless Days Conference

作者： Bouet, Mathieu dos Santos, Aldri L. Univ Paris 06 Lab Informat F-75016 Paris France Univ Fed Parana Dept Informat BR-81531990 Curitiba Parana Brazil

ISBN: (纸本)9781424428281

RFID is an automatic identification technology that enables tracking of people and objects. Both identity and location are generally key information for indoor services. An obvious and interesting method to obtain these two types of data is to localize RFID tags attached to devices or objects or carried by people. However, signals in indoor environments are generally harshly impaired and tags have very limited capabilities which pose many challenges for positioning them. In this work, we propose a classification and survey the current state-of-art of RFID localization by first presenting this technology and positioning principles. Then, we explain and classify RFID localization techniques. Finally, we discuss future trends in this domain.

关键词： RFID localization positioning algorithm

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Detector light response modeling for a thick continuous slab detector

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JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 2008年第7期45卷 634-638页

作者： Miyaoka, Robert S. Joo, Sung-Kwan Lee, Kisung Korea Univ Dept Radiol Sci Seoul 136703 South Korea Univ Washington Dept Radiol Seattle WA 98195 USA Korea Univ Sch Elect Engn Seoul 136701 South Korea

We investigate a method to improve the position decoding for thick crystal versions (i.e., >= 8 mm) of the continuous Miniature crystal element (cMiCE) PET detector by more accurately modeling, the detector light response function (LRF). The LRF for continuous detectors varies with the depth of interaction (DOI) of the detected photon. This variation in LRF can result in a positioning error for two-dimensional positioning algorithms. We explore a method to improve positioning performance by deriving two lookup tables, corresponding to the front and back regions of the crystal. The DETECT2000 simulation package was used to investigate the light response characteristics for a 48.8 mm by 48.8 mm by 10 (8) mill slab of LSO coupled to a 64-channel, flat-panel PMT. The data are then combined to produce the two-dimensional light collection histograms. Light collection histograms that have markedly non-Gaussian distributions are characterized as a combination of two Gaussian functions, where each Gaussian function corresponds to a DOI region of the crystal. The results indicate that modest gains in positioning accuracy are achieved near the central region of the crystal. However, significant improvements in spatial resolution and positioning bias are achieved for the corner section of the detector.

关键词： positioning algorithm light response modeling depth of interaction statistics-based positioning algorithm continuous slab detector continuous crystal positron emission tomography

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Survey of wireless indoor positioning techniques and systems

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IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART C-APPLICATIONS AND REVIEWS 2007年第6期37卷 1067-1080页

作者： Liu, Hui Darabi, Houshang Banerjee, Pat Liu, Jing Univ Illinois Dept Elect & Comp Engn Chicago IL 60612 USA Univ Illinois Dept Mech & Ind Engn Chicago IL 60607 USA

Wireless indoor positioning systems have become very popular in recent years. These systems have been successfully used in many applications such as asset tracking and inventory management. This paper provides an overview of the existing wireless indoor positioning solutions and attempts to classify different techniques and systems. Three typical location estimation schemes of triangulation, scene analysis, and proximity are analyzed. We also discuss location fingerprinting in detail since it is used in most current system or solutions. We then examine a set of properties by which location systems are evaluated, and apply this evaluation method to survey a number of existing systems. Comprehensive performance comparisons including accuracy, precision, complexity, scalability, robustness, and cost are presented.

关键词： indoor location sensing location fingerprinting positioning algorithm radio frequency (RF) wireless localization

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Performance comparisons of continuous miniature crystal element (cMiCE) detectors

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2006年第5期53卷 2513-2518页

作者： Ling, Tao Lee, Kisung Miyaoka, Robert S. Univ Washington Dept Phys Seattle WA 98195 USA Univ Washington Dept Radiol Seattle WA 98195 USA

In this paper, we investigated the performance characteristics of continuous miniature crystal element (cMiCE) detectors. Versions with a 25 mm by 25 mm by 4 mm-thick LSO crystal and with a 50 mm by 50 mm by 8 mm-thick LYSO crystal were evaluated. Both detectors utilize a 64-channel flat panel photomultiplier tube (PMT). The intrinsic spatial resolution for the detectors was evaluated using Anger (i.e., simple centroid) positioning and a statistics based positioning (SBP) algorithm. We also compared the intrinsic spatial resolution for the 8-mm-thick LYSO crystal using different reflective materials (e.g., TFE Teflon, white paint, and a polymer mirror film) applied on the entrance surface of the crystal. The average energy resolution was 20% for the 4-mm-thick LSO crystal and ranged from 16% to 21%, depending upon reflective material, for the 8-mm-thick LYSO crystal. The average intrinsic spatial resolution for the 4-mm-thick crystal was 1.8-mm full width at half maximum (FWHM) for Anger positioning to within 3 mm of the crystal's edge and 1.14-mm FWHM for SBP to within 2 mm of the edge. The average intrinsic spatial resolution for the 8-mm-thick crystal was 2.2-mm FWHM for Anger positioning to within 8 mm of the crystal's edge and 1.3- to 1.5-mm FWHM (depending on reflective material used) for SBP to within 2 mm of the edge. Intrinsic spatial resolution is reported without correcting for point source size. The point spot flux had a FWHM of about 0.52 mm. The SBP algorithm resulted in significant improvement in intrinsic spatial resolution, linearity of positioning result, and effective field of view (FOV) for our cMiCE detector.

关键词： continuous crystal position sensitive photomultiplier tube (PS-PMT) positioning algorithm small animal PET

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Development of a Monte Carlo simulation for APO-based PET detectors using a continuous scintillating crystal

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2006年第5期53卷 2563-2569页

作者： Clowes, Peter McCallum, Stephen Welch, Andy Univ Aberdeen Dept Biomed Phys & Bioengn John Mallard Scottish PET Ctr Aberdeen AB25 2ZD Scotland

We are currently developing a multilayer avalanche photodiode (APD)-based detector for use in positron emission tomography (PET), which utilizes thin continuous crystals. In this paper, we developed a Monte Carlo-based simulation to aid in the design of such detectors. We measured the performance of a detector comprising a single thin continuous crystal (3.1 mm x 9.5 mm, x 9.5 mm) of lutetium yttrium ortho-silicate (LYSO) and an APD array (4 x 4) elements;each element 1.6 mm(2) and on a 2.3 mm pitch. We showed that a spatial resolution of better than 2.12 mm is achievable throughout the crystal provided that we adopt a Statistics Based positioning (SBP) algorithm. We then used Monte Carlo simulation to model the behavior of the detector. The accuracy of the Monte Carlo simulation was verified by comparing measured and simulated parent datasets (PDS) for the SBP algorithm. These datasets consisted of data for point sources at 49 positions uniformly distributed over the detector area. We also calculated the noise in the detector circuit and verified this value by measurement. The noise value was included in the simulation. We show that the performance of the simulation closely matches the measured performance. The simulations were extended to investigate the effect of different noise levels on positioning accuracy. This paper showed that if modest improvements could be made in the circuit noise then positioning accuracy would be greatly improved. In summary, we have developed a model that can be used to simulate the performance of a variety of APD-based continuous crystal PET detectors.

关键词： avalanche photodiode (APD)-array continuous lutetium yttrium ortho-silicate (LYSO) Monte Carlo positioning algorithm

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A multidimensional scaling framework for mobile location using time-of-arrival measurements

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2005年第2期53卷 460-470页

作者： Cheung, KW So, HC City Univ Hong Kong Dept Elect Comp & Informat Technol Hong Kong Hong Kong Peoples R China

Localization of mobile phones is now a very popular research topic. In this paper, a simple algorithm is devised for mobile location estimation using time-of-arrival measurements of the signal from the mobile station received at three or more base stations, via modifying the classical multidimensional scaling technique, which has been developed for analyzing data obtained from physical, biological, and behavioral science. The bias and variance of the proposed algorithm are also derived. Computer simulations are included to corroborate the theoretical development and to contrast the estimator performance with several conventional approaches as well as the Cramer-Rao lower bound.

关键词： mobile terminal multidimensional scaling positioning algorithm time-of-arrival

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DOI-enhanced gamma-ray position detection for a small animal PET camera

DOI-enhanced gamma-ray position detection for a small animal...

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Nuclear Science Symposium/Medical Imaging Conference

作者： Lerche, Ch. W. Ros, A. Abellan, D. Palazon, J. A. Sanchez, F. Martinez, J. Sebastia, A. Benlloch, J. M. Univ Valencia CSIC Inst Fis Corpuscular Valencia Spain

ISBN: (纸本)0780392213

We studied the possibility of correcting edge artifacts caused by the Center of Gravity positioning algorithm (COG) within thick continuous scintillation crystals for gamma-ray imaging detectors. An enhanced charge division readout (CDR) together with multi-channel position sensitive photo-multiplier tubes allows the measurement of the 2(nd) moment of the scintillation light distribution within continuous and large-sized crystals. Using the 2(nd) moment together with the centroids provided by the CDR, the standard deviation sigma of the light distribution can be computed, providing a good estimator for the depth of interaction (DOI). We measured the sigma resolution at 81 positions of a test-detector's sensitive area and found an average resolution of 6 +/- 4.0mm. At the central region of 20 x 20mm(2) the performance of our method was with 3 +/- 0.8mm sigma resolution much better. The lowest observed value was 1.8mm. The 0(th), 1(X)(st), 1(Y)(st) and 2(nd) moments of the light distribution were also measured for the 81 positions and compared to predictions obtained by a model for the light distribution. Analytic studies show that the use of the first low order moments probably allows significant reduction of the DOI-caused border artifacts of the COG algorithm.

关键词： DOI PET positioning algorithm gamma ray imaging continuous scintillators

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Constrained location algorithm using TDOA measurements

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2003年第12期E86A卷 3291-3293页

作者： So, HC Hui, SP City Univ Hong Kong Dept Comp Engn & Informat Technol Kowloon Hong Kong Peoples R China

One conventional technique for source localization is to utilize the time-difference-of-arrival (TDOA) measurements of a signal received at spatially separated sensors. A simple TDOA-based location algorithm that combines the advantages of two efficient positioning methods is developed. It is demonstrated that the proposed approach can give optimum performance in geolocation via satellites at different noise conditions.

关键词： positioning algorithm weighted least squares time-difference-of-arrival

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