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Positioning, Navigation and Communication, 2009. WPNC 2009. 6th Workshop on

Date 19-19 March 2009

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Displaying Results 1 - 25 of 54
  • [Front cover]

    Page(s): c1
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    Freely Available from IEEE
  • [Title page]

    Page(s): i - ii
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    Freely Available from IEEE
  • Foreword

    Page(s): I - II
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    Freely Available from IEEE
  • Conference Chairs

    Page(s): III - IV
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    Freely Available from IEEE
  • Meeting information

    Page(s): V - X
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    Freely Available from IEEE
  • Table of contents

    Page(s): XI - XVI
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    Freely Available from IEEE
  • Indoor navigation with Low-Cost Inertial Navigation Systems

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB) |  | HTML iconHTML  

    This short document describes the evaluation of an indoor navigation system for pedestrians based on a small Low-cost inertial navigation system. The system components are explained and first investigations made on the campus of the Hafen City University (HCU) are shown. The focus of the investigation was the transition from outdoor to indoor scenarios. The aim of the project is the optimal integration of the sensor data from the small INS /GPS with other sensors e.g. cameras and GIS in a own Kalman Filter. The research is accomplished in the established Research Group dasiaDigital Citypsila of the HCU. The interdisciplinary team will focus on the development of valued added information and innovative services for the needs of citizens, employees, businesses and tourists. View full abstract»

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  • First results from supporting long coherent CDMA correlations by a MEMS INS and a Pedestrian Navigation System for HS-GNSS applications

    Page(s): 5 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (242 KB) |  | HTML iconHTML  

    This paper introduces a new approach to perform very long coherent integration for HS-GNSS applications developed under ESA funded project ldquoDINGPOSrdquo. Very long coherent integration is an approach to increase a GNSS receiver's post-correlation signal-to-noise ratio (SNR) and is especially helpful in the indoor scenario. For successful coherent integration very precise signal replicas have to be created. Taking into account an integration time in the second domain, the user motion has to be determined precisely. For that reason an Inertial Measurement Unit (IMU) has been chosen to track the user motion. Due to several constraints a MEMS-type IMU has to be used, hence the low performance of this sensor kind is denying the use of a classical strap-down calculation. The paper introduces an innovative approach using a Pedestrian Navigation System (PNS) as backbone for the system, taking comfort of the low drift and high macroscopic accuracy of that system. Using this position knowledge as a priori information, a corrected pseudo strap-down calculation can be used to produce a micro-trajectory of sufficient accuracy for replication of the GNSS signals. Finally an integration time of 2 seconds for a walking user shall be achieved. The paper discusses the need for that special procedure, the elements of the integrated system, the alternative processing of the micro-trajectory reproduction and discusses some initial results. View full abstract»

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  • Ray tracing supported precision evaluation for GPS indoor positioning

    Page(s): 15 - 22
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1275 KB) |  | HTML iconHTML  

    In this paper, we present an analysis of the influence of attenuation and multipath propagation on the GPS signal strength and the accuracy of the observed pseudoranges in an indoor scenario. Our investigations include experimental data from a u-blox high-sensitivity GPS receiver as well as simulation data derived from a ray tracing based deterministic GPS channel model. Our primary goal is to get a deeper understanding of the complex interactions of the GPS signals on their paths to indoor locations. In the first part we will verify that the indoor propagation of the satellite signals leads to characteristic and repeatable patterns in the observation data. Thanks to the sidereal repeatability of the GPS satellite constellation, this verification can be carried out using measurements performed on two successive days. In the second part we will present the ray tracing based deterministic simulation model used to perform the GPS outdoor-to-indoor channel simulations, show the results and compare the measured data and the results obtained with the ray tracer. View full abstract»

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  • GNSS-based trajectories for demanding applications

    Page(s): 23 - 28
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (809 KB) |  | HTML iconHTML  

    The Institute of Navigation and Satellite Geodesy of the Graz University of Technology is involved in many projects and developments to determine GNSS-based trajectories for demanding applications. Examples demonstrating the capabilities and limits of GNSS-based positioning under detrimental conditions are: positioning and guidance of visually impaired pedestrians, search and rescue applications, trajectory and attitude determination for airborne platforms, positioning and orientation of a mobile augmented-reality client, and trajectory and velocity determination in ski jumping. This paper gives an overview of each of the applications followed by a special insight into the last example which is characterized by high kinematics, partly shadowing of satellites, and updates of high frequency. View full abstract»

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  • The challenges of indoor environments and specification on some alternative positioning systems

    Page(s): 29 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (451 KB) |  | HTML iconHTML  

    This paper gives an overview of the current and near future positioning capabilities for indoor environments with focus on the research activities in that field at the Institute of Geodesy and Photogrammetry at the ETH Zurich. Object of study are those novel indoor-position systems that have the potential to achieve cm-level accuracy or better which is seen as a requirement for most geodetic applications. The focus is given on four alternative positioning systems where the GeomETH group at the ETH Zurich has made some experiences. These systems are iGPS, which is a system based on a rotating infrared laser fan, the Locata system that uses GNSS similar signals on pseudolites, the cricket ultra-sound system and a photogrammetric laser beam positioning systems (CLIPS) that is currently under development. As a result it can be noted that there are several unconventional positioning systems on their way that may compensate for the deficiencies of GNSS or total stations. View full abstract»

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  • A comparison of channel access concepts for high-precision local positioning

    Page(s): 37 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (122 KB) |  | HTML iconHTML  

    In this paper, we review channel access concepts for two competitive radiolocation systems, high-precision location system (HPLS) and local positioning radar (LPR), which share similar physical layers, but operate with different bandwidths. After a short review of the advantages of ultra-wideband signaling as employed by LPR, we spotlight tradeoffs in the servicing of multiple terminals. While HPLS supports both dynamic and static channel access, LPR is limited to static frequency multiplexing. The characteristics of these approaches are highlighted with theoretical analysis and simulation results. View full abstract»

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  • Overview of MAC layer enhancements for IEEE 802.15.4a

    Page(s): 43 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (94 KB) |  | HTML iconHTML  

    Ultra wideband impulse radio (IR-UWB) based on the IEEE 802.15.4a PHY standard offers unique features which are exploitable in MAC designs for wireless personal area networks (WPANs) and wireless sensor networks (WSNs) to improve performance and robustness. To achieve this, different strategies of cross-layer optimizations to the IEEE 802.15.4 MAC using features of UWB have been proposed. This paper compares current approaches and exposes individual advantages and disadvantages regarding energy efficiency and positioning. View full abstract»

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  • Hybrid Data Fusion techniques for localization in UWB networks

    Page(s): 51 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (302 KB) |  | HTML iconHTML  

    In this paper, we exploit the concept of data fusion in UWB (ultra wide band) localization systems by using different location-dependent observables. We combine ToA (time of arrival) and RSS (received signal strength) in order to get accurate positioning algorithms.We assume that RSS observables are usually available and we study the effect of adding ToA observables on the positioning accuracy. The proposed architecture of hybrid data fusion (HDF) is based on two stages: Ranging using RSS and ToA; and estimation of position by the fusion of estimated ranges. In the first stage, we propose a new estimator of ranges from RSS observables assuming a path loss model. In the second stage, a new ML estimator is developed to merge different ranges with different variances. In order to evaluate these algorithms, simulations are carried out in a generic indoor environment and Cramer Rao lower bounds (CRLB) are investigated. Those algorithms show enhanced positioning results at reasonable noise levels. View full abstract»

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  • NLOS channel identification and mitigation in Ultra Wideband ToA-based Wireless Sensor Networks

    Page(s): 59 - 66
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (327 KB) |  | HTML iconHTML  

    Recently, Ultra Wideband (UWB) Time Of Arrival (ToA)-based localization in Wireless Sensor Networks (WSNs) have received considerable attention. For a typical WSN operating in indoor environments, the localization performance can be degraded considerably due to the existence of non-line-of-sight (NLOS) channel conditions between the sensor nodes. In these channel conditions the ranging accuracy is degraded due to the attenuation and/or loss of the Direct Path (DP) signal which ultimately imposes a positive bias on the ToA-based distance estimation. As a result there is a need for robust algorithms that have the capability to identify and mitigate those NLOS ranging conditions. In this paper, we propose a novel, low complexity wireless channel condition estimation algorithm that identifies the condition of the channel. Based on the estimated ToA and Received Signal Strength (RSS) the algorithm identifies the channel condition which can be either LOS, NLOS - DP available, or NLOS - DP not available. A channel measurement campaign was conducted in an office environment and the measurement results confirms the validity of our algorithm. To integrate our channel condition estimation into the localization schemes, we propose two weight assignment schemes which generate either a ldquosoft weightrdquo or a ldquohard weightrdquo. Simulation results show that our estimator has robust performance with success rate of 85%. The simulations also show that by taking advantage of the channel condition estimation, we are able to reduce the RMSE of the localization estimate by over 40%. View full abstract»

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  • A 2-dimensional filter for UWB-localization in NLoS scenarios using BeamLoc

    Page(s): 67 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (259 KB) |  | HTML iconHTML  

    This paper deals with the simulation of an Ultra-wideband localization algorithm using a raytracer. A 2-dimensional filter is proposed and analyzed due to its capabilities to recover the Angle of Arrival in a Non-Line of Sight scenario. Moreover, it is shown that the filter enables to increase the Signal to Noise Ratio significantly. View full abstract»

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  • New communications service for aiding deep indoor localization

    Page(s): 71 - 76
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB) |  | HTML iconHTML  

    The success of navigation services in the mass consumer market will depend greatly on the service availability in urban canyons and moderate indoor environments. Just extending the observation period does not help when some satellite signals are stronger than others. This paper provides a new solution that arises with the introduction of the new two-tiered spreading codes for future Galileo and modernized GPS signals. The paper illustrates a new communications service that utilizes the secondary spreading codes of the new Galileo and GPS signals to circumvent the cross-correlation problem. The communications service aligns the secondary codes such that they are orthogonal over only a partial code period. View full abstract»

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  • A geolocation method using ToA and FoA measurements

    Page(s): 77 - 82
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (863 KB) |  | HTML iconHTML  

    In this paper, we describe a geolocation method using time of arrival (ToA) and frequency of arrival (FoA) measurements. The proposed method has been developed in particular for Global Navigation Satellite Systems (GNSS) like the American Global Positioning System (GPS) and the forthcoming European navigation system GALILEO. Most commercial GNSS receivers calculate their position based on ToA measurements. By exploiting the additional information of the FOA measurements we want to provide more robust position estimates under severe environmental conditions. Whereas the ToA method requires at least four measurements, with the described approach it is possible to provide a position estimate using less than four satellites in view. For the navigation algorithm we applied a least square (LS) approach. View full abstract»

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  • A new localization and Accuracy Analyzer for Wireless Sensor Networks using defective observations

    Page(s): 83 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1240 KB) |  | HTML iconHTML  

    The development of energy aware and precise localization algorithms is a challenging task in the development of wireless sensor networks (WSN). The achievable precision of the algorithms strongly depends on the accuracy of the measured observations (e.g. time of signal flight or received signal strength). In reality, observations are highly defective due to multiple effects (e.g. signal propagation). The geometrical conditions within the network can also affect the precision. It is therefore important to take the real characteristics of the observations into account as early as possible. This paper presents a new simulation tool to test geometrical conditions, different localization algorithms and measurements in WSNs either in the planing phase or after the localization process. Furthermore this tool enables the detection of outliers, to make accuracy statements and to analyze the determined position. View full abstract»

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  • A ranging scheme for asynchronous location positioning systems

    Page(s): 89 - 94
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2686 KB) |  | HTML iconHTML  

    In a real-time locating system which does not require time synchronization among nodes, it takes a very long time to complete a ranging process for a single location estimation. Long ranging time makes mobile nodes consume a significant amount of battery power and limits the number of mobile nodes that a single fixed node can handle during a specific time interval. Therefore, it is crucial to shorten the ranging time in asynchronous locating systems without degradation in ranging or locating accuracy. In this paper, we propose an asynchronous two-way ranging scheme which reduces ranging time by replying with multiple packets to a single ranging request. The algorithm reduces ranging time by 17% or more, compared to that of existing methods. View full abstract»

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  • Strategies to overcome border area effects of coarse grained localization

    Page(s): 95 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (301 KB) |  | HTML iconHTML  

    Localization of sensor nodes is one of the key issues in wireless sensor networks. Next to the ability, to assign a phenomenon to a position, localization is a precondition for sensor network algorithms like geographic clustering and routing. A simple approach for coarse grained localization is centroid localization (CL), which was firstly presented by Bulusu et al. and assumes regularly arranged beacons. The localization accuracy was improved by various centroid-based algorithms, which use approximate distances to improve location estimation through weighting beacons in range, e.g. weighted centroid localization (WCL). Nevertheless, all these approaches have in common an increased localization error near network borders. In this work, we investigate this error and present two strategies to reduce the localization error of border area nodes. View full abstract»

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  • UWB in heterogeneous access networks: EUWB proposal for application scenarios

    Page(s): 103 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    This paper presents a description of the scenarios identified within the European project EUWB (CoExisting Short Range Radio by Advanced Ultra-WideBand Radio) to integrate UWB-RT (Ultra-WideBand-Radio Technology) into heterogeneous access networks. Thanks to the implementation of these scenarios, the importance of the interworking and the coexistence between UWB-RT and other relevant technologies such as ADSL (Asymmetric Digital Subscriber Line), HSPA (High-Speed Packet Access), WiMAX (Worldwide Interoperability for Microwave Access) Wi-Fi, and BT (Bluetooth) will be proven. Consequently, interference studies among different radio interfaces are mandatory. Novel services based on the intrinsic characteristics of UWB-RT will also be presented, e.g., location-aware services, which will be demonstrated in shopping centre and firefighter localization scenarios. View full abstract»

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  • Evaluation of architectures and strategies for tracking mobile devices in UWB networks

    Page(s): 109 - 116
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB) |  | HTML iconHTML  

    Ultra wide-band radio technology is a good candidate for the development of indoor location & tracking networks. Some interesting application scenarios include relatively large and crowded areas such as shopping malls, but the application of short range UWB in these scenarios has to face different challenges, resulting in a trade-off between the positioning error and the amount of resources needed for location. In order to face these challenges, different system architectures and strategies for the acquisition and distribution of location information can be implemented. In order to assess the performance of the different alternatives in terms of accuracy and resources used for location, a simulation tool has been specifically developed, and the main results obtained are presented. View full abstract»

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  • Analysis of hopping strategies in multi-hop wireless networks

    Page(s): 117 - 123
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (158 KB) |  | HTML iconHTML  

    In this paper, the effects of different hopping strategies onto the performance of multi-hop wireless networks are analyzed. Employing the multi-hop aggregate information efficiency (MIEA), a simple metric able to capture several peculiarities of multi-hop networks, three policies of the relay selection (closest neighbor, most distant neighbor and random neighbor) are studied. The results show that 16-QAM with a single possibility of packet retransmission leads to the highest MIEA, regardless the hopping strategy. The analysis also reveals that the required power that optimizes the MIEA and the maximum MIEA have approximately the same value for the different hopping policies. However, in more realistic networks, where it is not possible to adjust the minimum power with the node density variation, the results suggest that the most suitable hopping strategy is to select the closest neighbor as the relay node, although the number of hops between source and destination tends to increase. Moreover, the results of this comparison reinforce the potential of location-awareness in the optimization of ad hoc networks. View full abstract»

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  • Aggregate information efficiency in IR-UWB ad-hoc single-hop WSNs

    Page(s): 125 - 128
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (98 KB) |  | HTML iconHTML  

    In this paper we evaluate the aggregate information efficiency IEA as a function of the node density for IR-UWB ad-hoc wireless sensor networks in single-hop scenarios by considering retransmission of misdetected packets. The metric of IEA was introduced and evaluated in a semi-analytical scenario.We apply the concept of the aggregate information efficiency to a packet-based network simulator with real IR-UWB nodes. View full abstract»

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