Calibration-free WLAN location system based on dynamic mapping of signal strength

Moraes, Luís F. M. de; Astuto, Bruno

doi:10.1145/1164783.1164799

Cited by 58 publications

(31 citation statements)

References 16 publications

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“…Here, we consider the probabilistic algorithm proposed by de Moraes and Nunes [8] due to its reported mean error of less than two meters and its foundation on a well-cited and understood RF propagation model [20]. The first step in the client location phase of this algorithm is to estimate the distance between each AP and the client.…”

Section: A Overviewmentioning

confidence: 99%

On the empirical performance of self-calibrating WiFi location systems

Turner

Savage

Snoeren

2011

2011 IEEE 36th Conference on Local Computer Networks

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Abstract-The pervasive deployment of 802.11 in modern enterprise buildings has long made it an attractive technology for constructing indoor location services. To this end, a broad range of algorithms have been proposed to accurately estimate location from 802.11 signal strength measurements, some without requiring manual calibration for each physical location. Prior work suggests that many of these protocols can be highly effectivereporting median errors of under 2 meters in some instances. However, there are few studies validating these claims at scale, nor comparing the algorithms in a uniform, realistic environment. Our work provides precisely this kind of empirical evaluation in a realistic office building environment. Surprisingly, we find that median errors in our environment are consistently greater than 5 meters and, counter-intuitively, that simpler algorithms frequently outperform their more sophisticated counterparts. In analyzing our results, we argue that unrealistic assumptions about access point densities and underlying variability in the indoor environment may preclude highly accurate location estimates based on 802.11 signal strength.

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Section: A Overviewmentioning

confidence: 99%

On the empirical performance of self-calibrating WiFi location systems

Turner

Savage

Snoeren

2011

2011 IEEE 36th Conference on Local Computer Networks

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“…In an isolated stable environment, it is possible to calculate the error using pre-measured RF signal map. Also, recent researches prove that the error in the dynamically changing environment can be calculated using the base stations [28]. However, since our work does not use any a priori environmental information and base stations, it is hard to use these methods.…”

Section: Filtering Algorithmmentioning

confidence: 99%

Rfid Based Collision-Free Robot Docking in Cluttered Environment

Kim

Kim²,

Chong³

2010

PIER

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Abstract-This paper proposes a radio frequency identification (RFID) based collision-free robot docking in cluttered environment. Physical distance estimation sensors are fused to the developed degree of arrival (DOA) guided robot docking system, and collision-avoidance function is implemented based on the vector field histogram technique. Additionally, new simple but efficient DOA filtering algorithm is developed based on the gain control according to the improved robot control algorithm, which enables the robot to move continuously. The experimental results show that the robot can move to target transponder even though the estimated DOA is blocked by obstacles. The success rate does not reach satisfactory level due to the limitation of the employed sensors and collision-avoidance algorithm, but it is proved that the collision-free docking becomes available without any priori map and reference stations.

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“…During the real-time phase, the wireless client measures the RSSI values from all of the APs in range and tries to match them with some of the RSSI values in the propagation map in order to estimate the STA's location. The main problem with map-based techniques is the calibration effort in the off-line phase, addressed in [16]. The accuracy of such systems depends on this procedure, which consists of physically moving a wireless device over each radio map grid point and capturing RSSI values from APs.…”

Section: Indoor Positioningmentioning

confidence: 99%

A Novel Wireless Positioning System for Seamless Internet Connectivity based on the WLAN Infrastructure

Manodham

Loyola

Miki

2007

Wireless Pers Commun

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Nowadays, several positioning systems are available for outdoor localization, such as the global positioning system (GPS), assisted GPS (A-GPS), and other systems working on cellular networks, for example, time difference of arrival (TDOA), angle of arrival (AOA) and enhanced observed time difference of arrival (E-OTD). However, with the increasing use of mobile computing devices and an expansion of wireless local area networks (WLANs), there is a growing interest in indoor wireless positioning systems based on the WLAN infrastructure. Wireless positioning systems (WPS) based on this infrastructure can be used for indoor localization to determine the position of mobile users. In this paper, we present a novel wireless positioning system, based on the IEEE 802.11b standard, using a novel access point (AP) with two transceivers to improve the performance of WPS in terms of accuracy of the location estimation and to avoid service connectivity interruption. In our proposed system, the novel AP uses the second transceiver to find information from neighboring mobile stations (STAs) in the transmission range and then sends information in advance to associated APs, which estimate the location of the STA based on an internal database. We also use a TDOA technique to estimate the location of the STA when there is not enough information in the database (in this case, the STA moves into a new area where the system has not run the calibration phase). Using TDOA, the database can be generated and updated automatically. The initial results from our simulations show that the proposed system provides higher accuracy of location estimation than other related work and does not interrupt the Internet connection for end users in contrast with other proposed schemes.

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Calibration-free WLAN location system based on dynamic mapping of signal strength

Cited by 58 publications

References 16 publications

On the empirical performance of self-calibrating WiFi location systems

On the empirical performance of self-calibrating WiFi location systems

Rfid Based Collision-Free Robot Docking in Cluttered Environment

A Novel Wireless Positioning System for Seamless Internet Connectivity based on the WLAN Infrastructure

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