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K.c. Ho - One of the best experts on this subject based on the ideXlab platform.
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on the use of a calibration emitter for source localization in the presence of sensor position uncertainty
IEEE Transactions on Signal Processing, 2008Co-Authors: K.c. Ho, Le YangAbstract:Sensor position uncertainty is known to degrade significantly the source localization accuracy. This paper investigates the use of a single calibration emitter, whose position is known to the sensor array, to reduce the loss in localization accuracy due to sensor position errors that are random. Using a Gaussian noise model, we first derive the Cramer-Rao lower bound (CRLB) for a time difference of arrival (TDOA)-based source Location Estimate with the use of a calibration source. The differential calibration technique that is commonly used in Global Positioning System through the use of a calibration source to mitigate the inaccuracy in satellite ephemeris data is analyzed. The analysis indicates that differential calibration in most cases cannot reach the CRLB accuracy. The paper then proceeds to propose an algebraic closed-form solution for the source Location Estimate using both TDOA measurements from the unknown and the calibration source. The proposed algorithm is shown analytically, under high signal-to-noise ratio (SNR) and small sensor position noise, or under moderate level of SNR and sensor position noise together with distant unknown and calibration sources, to reach the CRLB accuracy. Simulations are used to corroborate and support the theoretical development.
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passive source localization using time differences of arrival and gain ratios of arrival
IEEE Transactions on Signal Processing, 2008Co-Authors: K.c. HoAbstract:A source signal will be subject to different amounts of time-delay as well as attenuation when it reaches a number of spatially separated sensors. Both time-delay and attenuation are dependent on the distance between the source and the receivers. This paper performs a fundamental investigation of whether the gain ratios of arrival (GROAs), defined here as the ratio of the received signal amplitudes at the referenced sensor to the other sensors, can be utilized in conjunction with the time differences of arrival (TDOAs) to improve the source localization accuracy. We begin with a Gaussian random signal model and derive the Cramer-Rao lower bound (CRLB) of a source Location Estimate based on both GROAs and TDOAs. Our conclusion is that the improvement from GROAs increases when the factor c/omegao increases, where c is the signal propagation speed and omegao is the signal bandwidth. The paper proceeds to develop an algebraic closed-form solution for the source Location using GROAs and TDOAs. The algebraic solution is proved theoretically to reach the CRLB accuracy under the Gaussian data model. Numerical simulations are included to support and corroborate the theoretical developments.
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source localization using tdoa and fdoa measurements in the presence of receiver Location errors analysis and solution
IEEE Transactions on Signal Processing, 2007Co-Authors: K.c. Ho, Xiaoning Lu, L KovavisaruchAbstract:The accuracy of a source Location Estimate is very sensitive to the accurate knowledge of receiver Locations. This paper performs analysis and develops a solution for locating a moving source using time-difference-of-arrival (TDOA) and frequency-difference-of-arrival (FDOA) measurements in the presence of random errors in receiver Locations. The analysis starts with the Crameacuter-Rao lower bound (CRLB) for the problem, and derives the increase in mean-square error (MSE) in source Location Estimate if the receiver Locations are assumed correct but in fact have error. A solution is then proposed that takes the receiver error into account to reduce the estimation error, and it is shown analytically, under some mild approximations, to achieve the CRLB accuracy for far-field sources. The proposed solution is closed form, computationally efficient, and does not have divergence problem as in iterative techniques. Simulations corroborate the theoretical results and the good performance of the proposed method
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Solution and performance analysis of geoLocation by TDOA
IEEE Transactions on Aerospace and Electronic Systems, 1993Co-Authors: K.c. Ho, Yiu-tong ChanAbstract:One method of geoLocation is based on measuring the time difference of arrivals (TDOAs) of a signal received by three or four geostationary satellites. The received signals are cross-correlated to determine the TDOAs and a set of nonlinear equations are solved to produce the Location Estimate. An exact solution for the transmitter position is derived for the three or four receiver cases. Extension of the solution method to more receivers is straightforward. An analysis of the performance of the system is given, together with expressions for predicting the localization mean-square errors (MSEs) and bias, and the Cramer-Rao bound. Both precision in TDOA measurements and the relative geometry between receivers and transmitter affect the localization accuracy. The geometric factors act as multipliers to the TDOA variance in the bias and MSE formulae. A study of the dependency of the geometric factors on transmitter position and satellite spacings are provided, as well as simulation results. >
Michael R. Buehrer - One of the best experts on this subject based on the ideXlab platform.
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single anchor localizability in 5g millimeter wave networks
IEEE Wireless Communications Letters, 2020Co-Authors: Christopher E Olone, Harpreet S. Dhillon, Michael R. BuehrerAbstract:Fifth generation networks utilizing millimeter wave frequencies enable single-anchor localization to be performed via a line-of-sight (LOS) path or, as recently suggested, via non-line-of-sight (NLOS) paths exclusively. Thus, for a single base station-mobile pair, under a Boolean model (random positions, sizes, and orientations) of reflectors, and considering first-order reflections (in addition to the LOS path), this letter analytically derives the probability that the mobile is able to obtain an unambiguous Location Estimate ( i.e. , the mobile’s localizability ). This analysis also reveals that localization, via NLOS signals exclusively, is a relatively small contributor to the mobile’s overall localizability.
Otman A Basir - One of the best experts on this subject based on the ideXlab platform.
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vehicular collaborative technique for Location Estimate correction
Vehicular Technology Conference, 2008Co-Authors: Nabil Drawil, Otman A BasirAbstract:Awareness of a vehicle's precise Location in VANET is vital so that any vehicle can provide accurate data to its peers. Currently, typical localization techniques integrate the GPS receiver data and the measurements of the vehicle's motion. However, when the vehicle passes through an environment that creates multipath signals, these techniques fail to produce the high localization accuracy that they attain in open environments. The goal of this research is to minimize the multipath effect with respect to the localization accuracy of the vehicles in VANET. The proposed technique, IVCAL, takes advantage of the communications among the VANET vehicles in order to obtain more information from the vehicle's neighbours. The proposed technique integrates all these pieces of information with the vehicle's own data and applies optimization techniques to minimize the error in the Location Estimate. The simulation results in this paper show a decrease of up to 53% in the Location Estimate error compared to the error in the traditional techniques.
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VTC Fall - Vehicular Collaborative Technique for Location Estimate Correction
2008 IEEE 68th Vehicular Technology Conference, 2008Co-Authors: Nabil Drawil, Otman A BasirAbstract:Awareness of a vehicle's precise Location in VANET is vital so that any vehicle can provide accurate data to its peers. Currently, typical localization techniques integrate the GPS receiver data and the measurements of the vehicle's motion. However, when the vehicle passes through an environment that creates multipath signals, these techniques fail to produce the high localization accuracy that they attain in open environments. The goal of this research is to minimize the multipath effect with respect to the localization accuracy of the vehicles in VANET. The proposed technique, IVCAL, takes advantage of the communications among the VANET vehicles in order to obtain more information from the vehicle's neighbours. The proposed technique integrates all these pieces of information with the vehicle's own data and applies optimization techniques to minimize the error in the Location Estimate. The simulation results in this paper show a decrease of up to 53% in the Location Estimate error compared to the error in the traditional techniques.
Nabil Drawil - One of the best experts on this subject based on the ideXlab platform.
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vehicular collaborative technique for Location Estimate correction
Vehicular Technology Conference, 2008Co-Authors: Nabil Drawil, Otman A BasirAbstract:Awareness of a vehicle's precise Location in VANET is vital so that any vehicle can provide accurate data to its peers. Currently, typical localization techniques integrate the GPS receiver data and the measurements of the vehicle's motion. However, when the vehicle passes through an environment that creates multipath signals, these techniques fail to produce the high localization accuracy that they attain in open environments. The goal of this research is to minimize the multipath effect with respect to the localization accuracy of the vehicles in VANET. The proposed technique, IVCAL, takes advantage of the communications among the VANET vehicles in order to obtain more information from the vehicle's neighbours. The proposed technique integrates all these pieces of information with the vehicle's own data and applies optimization techniques to minimize the error in the Location Estimate. The simulation results in this paper show a decrease of up to 53% in the Location Estimate error compared to the error in the traditional techniques.
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VTC Fall - Vehicular Collaborative Technique for Location Estimate Correction
2008 IEEE 68th Vehicular Technology Conference, 2008Co-Authors: Nabil Drawil, Otman A BasirAbstract:Awareness of a vehicle's precise Location in VANET is vital so that any vehicle can provide accurate data to its peers. Currently, typical localization techniques integrate the GPS receiver data and the measurements of the vehicle's motion. However, when the vehicle passes through an environment that creates multipath signals, these techniques fail to produce the high localization accuracy that they attain in open environments. The goal of this research is to minimize the multipath effect with respect to the localization accuracy of the vehicles in VANET. The proposed technique, IVCAL, takes advantage of the communications among the VANET vehicles in order to obtain more information from the vehicle's neighbours. The proposed technique integrates all these pieces of information with the vehicle's own data and applies optimization techniques to minimize the error in the Location Estimate. The simulation results in this paper show a decrease of up to 53% in the Location Estimate error compared to the error in the traditional techniques.
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Improving the VANET Vehicles' Localizatoin Accuracy using GPS Receiver in Multipath Environments
2007Co-Authors: Nabil DrawilAbstract:The Vehicular Ad-hoc Network (VANET) has been studied in many fields since it has the ability to provide a variety of services, such as detecting oncoming collisions and providing warning signals to alert the driver. The services provided by VANET are often based on collaboration among vehicles that are equipped with relatively simple motion sensors and GPS units. Awareness of its precise Location is vital to every vehicle in VANET so that it can provide accurate data to its peers. Currently, typical localization techniques integrate GPS receiver data and measurements of the vehicle’s motion. However, when the vehicle passes through an environment that creates a multipath effect, these techniques fail to produce the high localization accuracy that they attain in open environments. Unfortunately, vehicles often travel in environments that cause a multipath effect, such as areas with high buildings, trees, or tunnels. The goal of this research is to minimize the multipath effect with respect to the localization accuracy of vehicles in VANET. The proposed technique first detects whether there is a noise in the vehicle Location Estimate that is caused by the multipath effect using neural network technique. It next takes advantage of the communications among the VANET vehicles in order to obtain more information from the vehicle’s neighbours, such as distances from target vehicle and their Location Estimates. The proposed technique integrates all these pieces of information with the vehicle’s own data and applies optimization techniques in order to minimize the Location Estimate error. The new techniques presented in this thesis decrease the error in the Location Estimate by 53% in the best cases, and in the worst case produce almost the same error in the Location Estimate as the traditional technique. Moreover, the simulation results show that 60% of the vehicles in VANET decrease the error in their Location Estimates by more than 13.8%. iii Acknowledgments I would like to thank Dr. Otman Basir, my supervisor, who offered me the opportunity to be a graduate student at the University of Waterloo and gave me the guidance and inspiration to start this thesis. I would like to thank the Libyan Ministry of Education who sponsored me during my study. I am also grateful to all the people who helped me directly or indirectly during my research.
Christopher E Olone - One of the best experts on this subject based on the ideXlab platform.
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single anchor localizability in 5g millimeter wave networks
IEEE Wireless Communications Letters, 2020Co-Authors: Christopher E Olone, Harpreet S. Dhillon, Michael R. BuehrerAbstract:Fifth generation networks utilizing millimeter wave frequencies enable single-anchor localization to be performed via a line-of-sight (LOS) path or, as recently suggested, via non-line-of-sight (NLOS) paths exclusively. Thus, for a single base station-mobile pair, under a Boolean model (random positions, sizes, and orientations) of reflectors, and considering first-order reflections (in addition to the LOS path), this letter analytically derives the probability that the mobile is able to obtain an unambiguous Location Estimate ( i.e. , the mobile’s localizability ). This analysis also reveals that localization, via NLOS signals exclusively, is a relatively small contributor to the mobile’s overall localizability.
