An Indoor Positioning Method using IEEE 802.11 Channel State Information (original) (raw)
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Robust indoor positioning provided by real-time RSSI values in unmodified WLAN networks
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The positioning methods based on received signal strength (RSS) measurements, link the RSS values to the position of the mobile station (MS) to be located. Their accuracy depends on the suitability of the propagation models used for the actual propagation conditions. In indoor wireless networks, these propagation conditions are very difficult to predict due to the unwieldy and dynamic nature of the RSS. In this paper, we present a novel method which dynamically estimates the propagation models that best fit the propagation environments, by using only RSS measurements obtained in real time. This method is based on maximizing compatibility of the MS to access points (AP) distance estimates. Once the propagation models are estimated in real time, it is possible to accurately determine the distance between the MS and each AP. By means of these distance estimates, the location of the MS can be obtained by trilateration. The method proposed coupled with simulations and measurements in a real indoor environment, demonstrates its feasibility and suitability, since it outperforms conventional RSS-based indoor location methods without using any radio map information nor a calibration stage.
Procedia Computer Science, 2014
Indoor positioning has emerged as a hot topic that gained gradual interest from both academia and industry. Accurate estimation is necessitated in a variety of location-based services such as healthcare, repository tracking, and security. Additional equipment for location sensing could be used for accurate estimation, but they are not widely used in general because those alternatives will cause specialization in brands and will be costly. Among all suggestions in literature including hardware and intense sophisticated computations, a versatile and low-cost location determination technology, which uses existing WLAN infrastructure of indoor environments, has been developed without incurring extra charge; this method is rising as a way of positioning. WLAN is capable to be used within an indoor positioning system soon in real environments. It is a good alternative in terms of accuracy, precision and cost, compared to similar systems. Especially with the common usage of smartphones and tablet PCs, it became the most easyto-use method, too. In this paper, we present a brief survey on such systems, methodologies, techniques and discuss advantages and disadvantages of each of these.
Improving the accuracy of indoor user location using IEEE 802.11 signals
TENCON 2010 - 2010 IEEE Region 10 Conference, 2010
The best candidate to determine a user location in indoor environment is by using IEEE 802.11 (Wi-Fi) signals, since it is more and more widely available and installed on most mobile devices used by users. Unfortunately, the signal strength, signals quality and noise of Wi-Fi, in worst scenario, fluctuate up to 33% because of the reflection, refraction, temperature, humidity, the dynamic environment, etc. This makes problems in determining a user location indoor. This study presents our current development on a light-weight algorithm, which is designed to be easy, simple but robust in producing the determination of user location. We study user location accuracy and the error levels to verify the mislead determination of the user location and improve the accuracy of the user location based on "multiple observers" ηk-Nearest Neighbor.
The ability to determine a user's location through an existing 802.11 wireless network has vast implications in the area of context-aware and pervasive computing. Such abilities have been developed mainly in the Linux environment to date. To maximize it s usefulness, a location determination system was developed for the more dominant Windows operation system. While being able to operate outdoors as well as indoors, this system succeeds where traditional GPS (Global Positioning Systems) fail, namely indoor environments. This system could benefit the large number of existing wireless networks and requires no additional hardware; only a few simple software downloads. The ability of a user to determine his/her location with the click of a button and begin using the services in the immediate vicinity or be shown a map leading to the desired area/item (a book in a library for example), are but two illustrations of the benefits that a wireless location determination system serve.
On Potentials and Limitations of a Hybrid WLAN-RFID Indoor Positioning Technique
International Journal of Navigation and Observation, Hindawi, special issue "Integrating Radio Positioning and Communications: New Synergies", Vol. 2010, 11 pages, 2010
This paper addresses the important issue of position estimation in indoor environments. Starting point of the research is positioning techniques that exploit the knowledge of power levels of RF signals from multiple 802.11 WLAN APs (Access Points). In particular, the key idea in this paper is to enhance the performance of a WLAN fingerprinting approach by coupling it to a RFIDbased procedure. WLAN and RFID technologies are synergistically used to provide a platform for a more performing positioning process, in which the very strong identification capabilities of the RFID technology allow to increase the accuracy of positioning systems via WLAN fingerprinting. The algorithm performance is assessed through general and repeatable experimental campaigns, during which the main algorithm parameters are dimensioned. The results testify both to the feasibility of the solution and to its higher accuracy (attainable at very reduced costs) compared to traditional positioning techniques.
Indoor positioning systems have received increasing attention for supporting location-based services in indoor environments. WiFi-based indoor localization has been attractive due to its open access and low cost properties. However, the distance estimation based on received signal strength indicator (RSSI) is easily affected by the temporal and spatial variance due to the multipath effect, which contributes to most of the estimation errors in current systems. In this work, we analyze this effect across the physical layer and account for the undesirable RSSI readings being reported. We explore the frequency diversity of the subcarriers in OFDM systems and propose a novel approach called FILA, which leverages the channel state information (CSI) to build a propagation model and a fingerprinting system at the receiver. We implement the FILA system on commercial 802.11 NICs, and then evaluate its performance in different typical indoor scenarios. The experimental results show that the accuracy and latency of distance calculation can be significantly enhanced by using CSI. Moreover, FILA can significantly improve the localization accuracy compared with the corresponding RSSI approach.
Positioning is the most attractive technology today. Various technologies are used now days for positioning purpose. GPS is mainly used for outdoor environment. Non-suitability of GPS in indoor conditions because of its NLOS conditions and signal attenuation has lead to several other techniques of indoor positioning. This paper compares few indoor positioning methods and proposes indoor positioning system using tri-lateration method which uses RSSI data from wi-fi access points to do localization in indoor environment.