2,759 research outputs found

    Optimization of duty cycles for LED based indoor positioning system

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    Intelligent Indoor Parking

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    Nowadays positioning based navigation is an integrated part of our everyday’s routine. Hence, it is hard to succeed without a GPS based navigation system in a bigger city today. However, indoor positioning and navigation are still in their infancy, although these services would be desirable in many areas. One obvious application domain is vehicle navigation in a parking garage. The use of an indoor vehicle navigation system is convenient for the drivers, decreases the unnecessary circling in the garage and reduces air pollution. In this paper, we introduce our iParking indoor positioning and navigation system which has been under development. Our system monitors the occupancy of the parking lots, and with the aid of a Wi-Fi based background wireless infrastructure tracks the position of the vehicle entering the parking garage and navigates the driver to an appropriate free parking lot. Lot selection is handled at the entry point of the garage based on simple preferences, eg., the closest disabled parking space. The navigation interface is the driver’s smartphone. Currently, we have been implementing a prototype of our iParking system in a parking garage of a shopping mall for demonstration purposes

    Parking Assistance System for Indoor Environment

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    In the last decade, indoor location based applications, such as touristic guide in museums or shopping guidance in supermarkets, have been developed rapidly requiring suitable and accurate indoor positioning. However, location sensing in indoor environments is a challenging task and an intensively researched topic. Fortunately, wireless technologies can help us derive location information. In this paper, we propose and introduce our positioning and navigation system for indoor parking garage environment, called iParking, which has been under development. The iParking system collects real-time parking lot occupancy data, and tracks and navigates vehicles entering the parking garage to a preselected, e.g., the closest to the favorite shop, free parking lot. The driver’s smartphone is used as the navigation interface. The system is built on a background Wi-Fi infrastructure making the deployment and maintenance economical. Currently, we have been implementing a prototype of our iParking system in a parking garage of a shopping mall for demonstration purposes

    Enhancing the Performance of Propagation Model-Based Positioning Algorithms

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    Object localization in wireless networks through Received Signal Strength (RSS) measurements requires a precise estimation of the signal attenuation model in order to produce meaningful results. The popular lognormal channel model, widely adopted to describe the signal strength attenuation as a function of the distance between nodes, turns out to be too simplistic when applied to a real scenario. In this paper, we analyze two possible improvements to this model: on one hand, we build a different channel model for each reference node in the network, with the aim of tackling the anisotropy of the environment. On the other hand, we explicitly append to the lognormal model a term to account for walls attenuation. A thorough experimental testbed demonstrates the potentials of the two approaches, with the second one being especially useful to counteract the effect of the limited sensitivity of practical wireless receivers

    Optical wireless communication based indoor positioning algorithms: performance optimisation and mathematical modelling

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    In this paper, the performance of the optimal beam radius indoor positioning (OBRIP) and two-receiver indoor positioning (TRIP) algorithms are analysed by varying system parameters in the presence of an indoor optical wireless channel modelled in line of sight configuration. From all the conducted simulations, the minimum average error value obtained for TRIP is 0.61 m against 0.81 m obtained for OBRIP for room dimensions of 10 m × 10 m × 3 m. In addition, for each simulated condition, TRIP, which uses two receivers, outperforms OBRIP and reduces position estimation error up to 30%. To get a better understanding of error in position estimation for different combinations of beam radius and separation between light emitting diodes, the 90th percentile error is determined using a cumulative distribution frequency (CDF) plot, which gives an error value of 0.94 m for TRIP as compared to 1.20 m obtained for OBRIP. Both algorithms also prove to be robust towards change in receiver tilting angle, thus providing flexibility in the selection of the parameters to adapt to any indoor environment. In addition, in this paper, a mathematical model based on the concept of raw moments is used to confirm the findings of the simulation results for the proposed algorithms. Using this mathematical model, closed-form expressions are derived for standard deviation of uniformly distributed points in an optical wireless communication based indoor positioning system with circular and rectangular beam shapes

    Design and analysis of collision reduction algorithms for LED-based indoor positioning with simulation and experimental validation

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    In this paper, we develop a low complexity indoor positioning system (IPS) and design a lightweight, low-cost, and wearable receiver for it. The accuracy of proximity-based LED IPS has been improved using overlap between LED beams but LED packets in the overlap region are subject to collisions. In this paper, we design collision handling algorithms for the IPS that considers building and lighting infrastructures. Mathematical analyses of the proposed algorithms are done and models for the probability of collisions are developed. The models, which are verified using simulations, are used to calculate the time required for position update called positioning time. Analysis of the positioning time is done for single and multiple receivers systems and validated with experimental measurements. Results show positioning error as low as 56 cm with a positioning time of about 300 ms for slotted unsynchronized systems and 500 ms for unslotted unsynchronized systems which makes the developed system pragmatic and appropriate for human positioning

    Experimental Demonstration of an Indoor VLC Positioning System Based on OFDMA

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    We propose an indoor visible light communication (VLC) and positioning system using the orthogonal frequency division multiplexing access (OFDMA) scheme, which can provide both indoor positioning and communications. Three subcarriers with the maximum received signal intensity with respect to three light-emitting diodes (LEDs) are selected for indoor positioning based on the trilateration algorithm. The experiment results show that the proposed system with quadrature phase shift keying (QPSK) mapping offers a mean positioning error and an error vector magnitude of 1.68 cm and more than 15 dB, respectively
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