Conference Paper

BlueBot: Asset tracking via robotic location crawling

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Abstract

From manufacturers, distributors, and retailers of consumer goods to government departments, enterprises of all kinds are gearing up to use RFID technology to increase the visibility of goods and assets within their supply chain and on their premises. However, RFID technology alone lacks the capability to track the location of items once they are moved within a facility. We present a prototype automatic location sensing system that combines RFID technology and off-the-shelf Wi-Fi based continuous positioning technology for tracking RFID-tagged assets. Our prototype system employs a robot, with an attached RFID reader, which periodically surveys the space, associating items it detects with its own location determined with the Wi-Fi positioning system. We propose four algorithms that combine the detected tag's reading with previous samples to refine its location. Our experiments have shown that our positioning algorithms can bring a two to three fold improvement over the positional accuracy limitations in both the RFID reader and the positioning technology.

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... High-speed contactless identification ability without line-of-sight (LOS) is a major advantage of the RFID (radio frequency identification) technology, which in turn makes object tracking a very important electromagnetic application [1][2][3][4]. Positioning analysis [2][3][4][5][6][7][8][9][10][11][12][13][14] is essentially important in locating the objects of interest in a certain enterprise. The knowledge of the placement, movement, and coverage of a reader is fundamental in locating the objects smoothly and efficiently. ...
... In this paper, a new positioning analysis with mobile readers is proposed, where readers can be mobilized by attaching a reader to a robot [11,12,16] that can move around the premise in a zigzag pattern and the position of the item is calculated by means of RSS model. The number of mobile readers required is devised from the proposed zigzag pattern while the velocity, interrogation range, and time needed for the reader will be recorded for complete scanning of the whole area. ...
... With the zigzag pattern, the estimated position of a tag is relatively accurate compared to other methods as explained later. In the proposed method, the maximum time required to find all the available tags in the premise is set to 5 s (to ensure a short period of time), which can be seen as an advantage compared to other mobile reader based positioning systems [11,12,15,16]. The proposed method is studied thoroughly by scattering a number of tags in different scenarios. ...
Article
Full-text available
This paper proposes a new positioning system utilizing mobile readers that are programmed to move in a zigzag pattern to locate the tags. The proposed zigzag mobility pattern is able to cover an area completely within a given period, determine optimal number of required mobile readers, and find out reader placement and movement pattern. The received signal strength (RSS) model is used to exchange the information over a short range by estimating the position of the tag by means of distance information between the reader and the tag. The results obtained from this study point out that the proposed method is able to provide near exact tag position. The proposed method can achieve average error as low as 0.6 m. With this proposed method, the scanning of large areas, such as warehouses, libraries, and storage areas can be done very quickly. Mobile reader is proposed because it is cost-effective, fast, and is able to provide relatively accurate results.
... It may even cause restructure of the network. Again sensor mapping in database also needs to undergo updates by the System Administrators which also costs considerably [1]. Wireless Location Systems like Active badge, bat, Cricket [8, 9] uses infrastructure for locating objects. ...
... Both academic and industry researches of asset tracking systems in [2, 3, 4, 6] deploy access points or receiving stations which doesn't fit in pervasive environment in the true sense. BlueBot from IBM TJ Watson Lab [1] uses robot random walk approach to get rid of static receiving stations, but it too suffers from the cost constraint. RENWINS project by UCLA [2] supports multiple Radio Frequency signals and SmartLOCUS from HP [3] supports autonomic setup of the nodes. ...
... Nibble uses a Bayesian model for predicting the likely origin of a signal based on signal quality observed at access points [10]. The BlueBot Asset Tracking System by IBM TJ Watson Lab [1] uses RFID tags as the object identifiers. The system has eliminated the necessity of infrastructures and introduces a random robot walk to take repeated sample of the signal strengths from different spots. ...
Conference Paper
From container terminals, healthcare services, libraries to household, the role of Asset Tracking Applications has become indispensable. As the organizations grow, so do their volume of assets, soon it becomes very cumbersome to track these assets in real time and accurately prepare a financial report to avoid overbuys. Rapid development of Wireless Area Network and Radio Frequency transmitting active and passive devices like RFID tags have bolstered the deployment of Wireless Asset Tracking applications in all these disciplines. But apart from organizations where costly network infrastructures are in place to support such a reliable asset tracking task, the areas like ports, warehouses, truck stops, parks, mines, rescue spots still suffer from appropriate solutions that can cope with the adverse scenario of being devoid of infrastructure. Even high end Location Based Systems (LBS) like GPS are not scaled well in such situations. To meet these challenges, our approach presents a common platform that can locate different active and passive RF transmitting objects over the range of distances on small handheld devices. To effectively utilize the resources of the constrained handheld devices like PDA and cell phones, a light weight algorithm has been used. Our approach follows an extensible and modular architecture which offers applications from different platforms to customize and extend their functionalities. Smart Tracker has been implemented and evaluated with PDAs, RFID tags, WiFi sources for both indoor and outdoor applications.
... Location tracking and monitoring, location sensing or location-aware systems are terms used interchangeably to define the availability and the ability of an object that is being located and monitored constantly (Mak and Furukawa 2008;Chen, Shi, Hong, and Chen 2009;Martinez et al. 2009;Song, Wang, Hong, and Wang 2009;Mitilineos and Thomopoulos 2010;Reza, Pillai, Dimyati, and Geok 2010). Radio-frequency identification (RFID) location tracking system is making huge impacts to keep track of the tagged items almost instantaneously (Ni, Liu, Lau, and Patil 2004;Patil, Munson, Wood, and Cole 2005;Lahiri 2006;Tan, Wasif, and Tan 2008;Reza and Geok 2009a,b;Ko 2010;Oztekin, Pajouh, Delen, and Swim 2010;. The main limiting factor of the various existing RFID positioning and tracking systems is imprecise localisation (Ni et al. 2004;Patil et al. 2005;Ko 2010;Oztekin et al. 2010). ...
... Radio-frequency identification (RFID) location tracking system is making huge impacts to keep track of the tagged items almost instantaneously (Ni, Liu, Lau, and Patil 2004;Patil, Munson, Wood, and Cole 2005;Lahiri 2006;Tan, Wasif, and Tan 2008;Reza and Geok 2009a,b;Ko 2010;Oztekin, Pajouh, Delen, and Swim 2010;. The main limiting factor of the various existing RFID positioning and tracking systems is imprecise localisation (Ni et al. 2004;Patil et al. 2005;Ko 2010;Oztekin et al. 2010). To overcome this problem, the two-dimensional (2D) geometric square grid covering-based positioning system was introduced in our article (Tan et al. 2008;Reza and Geok 2009a;), which has already been proved to be superior and extremely accurate when compared with the existing location sensing systems. ...
... The superiority of the proposed 3D tracking system has been further proved by comparing with other existing approaches, as given in Table 1 (Reza and Goek 2009a). The obtained results show that the proposed 3D tracking system clearly outperforms the existing 2D tracking systems, such as LANDMARC and BlueBot (Ni et al. 2004;Patil et al. 2005) in all three aspects, namely: (1) without obstacles (2) with obstacles and (3) with the highest attenuation factor. It is also found that the performance of grid-based 3D tag tracking method is better than (without obstacles) or even comparable (with obstacles and highest attenuation effect) than that of 2D square gridbased positioning system (Reza and Goek 2009a) as antenna placement in 3D offers more intersections of circular radio coverage with one another in every direction of X-, Y-and Z-axes (that results in outstanding tracking accuracy). ...
Article
Full-text available
Recent trend shows that one of the crucial problems faced while using radio frequency to track the objects is the inconsistency of the signal strength reception, which can be mainly due to the environmental factors and the blockage, which always have the most impact on the tracking accuracy. Besides, three dimensions are more relevant to a warehouse scanning. Therefore, this study proposes a highly accurate and new three-dimensional (3D) radio frequency identification-based indoor tracking system with the consideration of different attenuation factors and obstacles. The obtained results show that the proposed system yields high-quality performance with an average error as low as 0.27m (without obstacles and attenuation effects). The obtained results also show that the proposed tracking technique can achieve relatively lower errors (0.4 and 0.36 m, respectively) even in the presence of the highest attenuation effect, e = 3.3 or when the environment is largely affected by 50% of the obstacles. Furthermore, the superiority of the proposed 3D tracking system has been proved by comparing with other existing approaches. The 3D tracking system proposed in this study can be applicable to a warehouse scanning.
... However, for the system to be cost-effective the RFID tags used for most recent applications are passive, which puts a limit on the interrogation range of the reader. Actually, ranges of more than 1.5 m are not easily achieved by passive technology (Patil, Munson, Wood and Cole 2005). According to Finkenzeller (2003), passive RFID readers operating in the ultra high frequency (UHF) band typically have an interrogation range of 3-5 m. ...
... The accuracy of this approach is determined by the number of readers required, the placement of these readers and the power level of each reader. The BlueBot system (Patil et al. 2005) combines passive RFID technology with a Wi-Fi based (802.11b) system to enable a periodic asset-location sweep. ...
... Besides the RFID positioning technologies discussed earlier, the most recent research work has been done in probe card management systems for throughput improvement via tracking of probe cards (Ingamells and Kober 2005), in the field of food technology to create a safer food supply chain in order to provide full traceability of food products (Jones 2006), and in health delivery networks to help manage the tracking process (Sangwan, Qiu and Jessen 2005). Different tracking technologies are characterised by distinguishing between continuity in space and continuity in time reported by Patil et al. (2005). A space continuous tracking system is able to track the position of objects anywhere in the space of interest whereas a time continuous tracking system is able to provide position at any point in time. ...
Article
Full-text available
One of the fundamental constraints in radio frequency identification (RFID) large scale deployment, such as in warehouse RFID deployment, is the positioning of RFID reader antennas to efficiently locate all the tagged objects distributed in a dense RFID reader environment. For tracking the tagged objects in a dense RFID deployment, the required number of reader antennas must be optimised in order to reduce the overall cost. This study proposes highly accurate square and hexagonal grid-based positioning and tracking techniques mainly for use indoors and includes performance comparison of both of these grids. The study involves the design of the square and hexagonal grid reader antenna networks and position calculation using a diffusion algorithm. Both of these grids of RFID antenna positioning present a solution for the problem of the placement pattern of RFID reader antennas in a dense reader environment, hence an optimal number of required reader antennas and guaranteed coverage can be achieved. This study also presents a path loss model that can be applied to predict the radio signal strength information at a certain distance. The proposed diffusion algorithm estimates RFID tag position by using distance information between the reader and the tag. The obtained results show that a square grid can yield higher positioning accuracy compared to the hexagonal grid. The obtained results further show that the proposed tracking techniques can achieve an average positioning error below 1 m, which is 85% better in some cases than the results obtained by other known methods.
... Moreover, grid covering reader antenna network allows continuous position estimation in space and time. The continuous tracking technologies can be generated towards tracking items of high value such as emergency medical equipments or surgeon [14]. ...
... Reducing sensing radius of a reader and nicely formulated grid reader antenna network are two strategic moves to improve the accuracy in this study. The statistical averages algorithm [14] is proposed in this paper for position estimation through grid reader antenna network. This positioning algorithm computes the location coordinates of the tagged object by statistical average of the reader antenna's location when it detects any tag. ...
Article
Full-text available
One of the biggest challenges in RFID (radio frequency identification) large scale deployment, such as in warehouse RFID deployment, is the positioning of RFID reader antennas to efficiently locate all the tagged objects distributed at RFID reader environment. This paper has investigated a novel location sensing system based on geometric grid covering algorithm that can use any passive or active RFID standard for positioning or tracking objects inside buildings. This study involves design of RFID reader antenna network which focuses on placing the reader antennas on a grid to cover all the tags distributed at two dimensional planes and position calculation using statistical averages algorithm. The statistical averages algorithm simply computes the location coordinates of the tagged object by statistical average of the reader antenna’s location. The proposed grid of reader antennas can assist in minimizing the actual number of reader antennas required for RFID large scale deployment. The proposed prototype system is a simpler positioning system which presents the solution of placement pattern of RFID reader antennas, gives less complicated mathematical calculation, and is able to provide a high degree of accuracy. The obtained results show that the proposed location sensing system can achieve better positioning accuracy as compared to existing positioning system and in some cases accuracy improvement of about 50% can be reached.
... It also provides significant improvement on items identification, tracking the objects and stock control. As RFID allows the wireless storage and automatic retrieval of data, as in [1], many companies are realizing its importance of increasing performance within the supply chain. Consider a typical library, in which each book has its own assigned location in order to get easy assessment. ...
... 116.4975 (1) s2 + 12.442s + 12.69 ...
Conference Paper
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Searching and sorting misplaced books is a difficult task often carried out by the library personnel. Quite often, librarians are busy with searching misplaced books which are left in wrong locations by library users. It is quite difficult and almost impractical to place back all books to their assigned locations daily. To overcome this, radio frequency identification (RFID) based Intelligent shelving system has been proposed to provide an efficient mechanism of books management monitoring through wireless communication between the RFID reader and the books. It is quite essential for the proposed system to have a smooth motion for the RFID reader during the shelving operation; otherwise acquired data will have no value due to inconsistency in reading the tags. Consequently, in this paper, the performance of RFID reader motion and tags data management such as retrieving information, matching with database, sorting out the order and displaying the status of books locations are discussed. A prototype consisting of monitoring PC with embedded controller, two dc motors with drivers, RFID reader and aluminum frame stick on rack have been developed. The performance of the proposed system has been investigated and found to be satisfactory. And it has a lot of potential applications, especially in its ability to alleviate the intensive labors and efforts in shelving cbooks.
... The accuracy of this approach is determined by the number of readers required, the placement of these readers, and the power level of each reader. BlueBot system [11] combines passive RFID technology together with Wi-Fi based (802.11b) system to enable a periodic asset-location sweep. ...
Article
Full-text available
The study and analysis of RFID (radio frequency identification) reader positioning is important for RFID large-scale deployment. Therefore, the purpose of this research is to investigate the art of RFID reader positioning in order to develop a highly accurate positioning and tracking system for usage inside a building and also to optimize the tracking performance that can be applied to different active and passive RFID standards. This study involves design of square grid RFID reader network and position calculation using diffusion algorithm. Square grid network presents the solution of placement pattern of RFID readers, hence optimal number of required readers and guaranteed coverage can be achieved. The proposed diffusion algorithm makes use of distance information between the reader and the tag to estimate the RFID tag position. This study has also introduced a probabilistic mathematical model to maintain coverage of the unit square region and to ensure connectivity of the proposed square grid network. The effectiveness of the diffusion algorithm is evaluated in this study and the obtained results show satisfactory performance. The obtained results show that the proposed positioning system can achieve average positioning error below 1m with different RFID reading ranges and in some cases accuracy improvement of about 65% can be reached than the results obtained by known positioning system. It is also found that the proposed diffusion algorithm together with square grid can bring approximately 50–85% improvement on raw accuracy provided by only square grid method. KeywordsPositioning–Tracking–RF Localization–RFID Reader Network–RFID
... They also have a fast response time and the cost effectiveness, life time and low maintenance are important benefits if you use passive tags, because no batteries are needed. Some examples are [13] [14]. The main difference between these approaches and ours is that our system is based on passive RFID technology, while others use the technology as a calibration or helping system that is secondary to the main system (radio frequency + INS, for instance) in order to improve main system precision. ...
Article
Full-text available
GPS seems to be the best solution to develop outdoor location systems, but performance of these systems is not good enough to locate entities within indoor environments, mainly if accuracy and precision are required. In this article we propose a tracking indoor system based on passive RFID technology that is able to accurately locate autonomous entities, such as robots, people, etc, within a defined surface. In order to validate the proposal, we compared our system technology performance against other alternatives built on different technologies (Wi-Fi, Bluetooth, IrDA, ultrasound, etc). We also include the system evaluation and final remarks with future improvements.
... O BTAINING location information indoors is becoming important for many applications, including navigation tools for humans and robots, building mapping, interactive games, resource discovery, asset tracking and location-aware sensor networking [1], [2], [3], [4], [5], [6], [7]. GPS works well outdoors, but fails in indoor environments due to signal attenuation by the building fabric [8]. ...
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This paper presents a novel reference-free ultrasonic indoor location system. Unlike most previous proposals, the mobile device (MD) determines its own position based only on ultrasonic signals received at a compact sensor array and sent by a fixed independent beacon. No radio frequency or wired timing reference signal is used. Furthermore, the system is privacy aware and one way in that the receive-only MD determines its own position based on ultrasonic signals received from fixed transmit-only beacons. The MD uses a novel hybrid angle of arrival (AoA)–time of flight (ToF) with timing lock algorithm to determine its location relative to the beacons with high accuracy. The algorithm utilizes an AoA-based location method to obtain an initial estimate of its own location. Based on this, it estimates the timing offsets (TOs) between the MD clock and the beacon transmissions. The average TO and the known periodicities of the beacon signals are then used to obtain a second more accurate MD location estimate via a ToF method. The system utilizes wideband spread spectrum ultrasonic signaling in order to achieve a high update rate and robustness to noise and reverberation. A prototype system was constructed, and the algorithm was implemented in software. The experimental results show that the method provides 3-D accuracy better than 9.5 cm in 99% of cases, an 80% accuracy improvement over the conventional AoA-only method.
... R ANGE measurement is important for many applications, including navigation tools for humans and robots, building mapping, interactive games, resource discovery, asset tracking and location-aware sensor networking [1][2][3][4][5][6][7][8]. Many range measurement techniques have been introduced in the literature, making use of various technologies such as lasers, infrared, radio frequency and ultrasonic signals [8][9][10][11]. ...
Article
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This paper presents a novel method for ultrasonic range estimation. The method uses a wideband Frequency Hop Spread Spectrum (FHSS) ultrasonic signal to increase robustness to noise and reverberation. The method applies cross-correlation with earliest peak search and a novel minimum variance search technique to correct the error in the cross-correlation Time of Flight estimate to within one wavelength of the carrier before applying a phase shift technique for sub-wavelength range refinement. The method can be implemented digitally in software and only requires low cost hardware for signal transmission and acquisition. Experimental results show an accuracy of better than 0.5 mm in a typical office environment.
... As such, RFID is regarded as a new generation of Auto-ID technology (Derakhshan et al., 2007). It has been widely applied in manufacturing (Liu et al., 2004;Huang et al., 2007;Huang et al., 2008a;Huang et al., 2008b), supply chain management (Michael and McCathie, 2005;Delen et al., 2007) and other related industries involving real-time object tracking purpose, such as asset tracking (Bhanage et al., 2007;Patil et al., 2008), drug safety and healthcare (Wu et al., 2005;Hakim et al., 2006;Wang et al., 2006b), etc. ...
In order to face up with classic manufacturing challenges such as high work in progress (WIP) inventories, complexity in production planning and scheduling, and low labour and machine utilisation, many manufacturing companies made their efforts in implementing RFID (Radio Frequency Identification Devices) throughout the manufacturing workshops. Through this way, all production data in manufacturing fields can be obtained in real time, and it improves the flexibility and responsivity to the changing market for the companies. However, at the same time the RFID deployment also introduces a new challenge which requires an effective and efficient method to handle the large amounts of events. This paper proposes an application framework for a real-time Complex Event Management System (CEMS) based on RFID equipments deployment. With the use of Complex Event Processing (CEP) technologies, this system allows users to obtain interested and meaningful information from large numbers of primitive events captured from the RFID devices deployed in manufacturing shop-floor in real time. This paper presents the RFID deployment infrastructure first, and then system design of the CEMS is proposed.
... LANDMARC [10] is an active RFID calibrated positioning system in which fixed RFID tags are used to serve as reference points. BlueBoT [11] system combines passive RFID technology together with Wi-Fi based (802.11b) system to enable a periodic asset-location sweep. ...
Article
Recent trend have shown the wide spread of RFID application in various areas in line with the realization of low cost RFID tags and increasing worldwide commonality and compatibility. One of the important RFID applications is in object tracking and positioning due to its ability of high speed contactless identification in non-line of sight (NLOS) shared medium. This paper proposes a highly accurate square grid based RFID positioning and tracking technique mainly for use in indoor. It involves design of square grid RFID reader antenna network and position calculation using diffusion algorithm. Square grid reader antenna network presents the solution of placement pattern of RFID reader antennas, hence optimal number of required RFID reader antennas and coverage can be achieved. Diffusion algorithm is a means of exchanging information over short range in estimating RFID tag position by using distance information between reader and tag. The proposed square grid tracking and positioning method is evaluated and compared with the existing positioning method such as Wi-Fi based positioning method and BlueBoT system. The obtained results indicate that the proposed method can achieve average positioning error below 1 m and in some cases error as low as 0.3 m can be reached.
... One of such systems namely gpsOne™ developed by Qualcomm has been applied in CDMA networks, to provide high accuracy indoor and outdoor location based services (Qualcomm, 2004). Moreover, low-cost, high speed communication and positioning enabled systems such as Wi-Fi (Patil, et al., 2005) and Ultrawide Band (Schroeder, Galler and Kyamakya, 2005) technologies are emerging the Hong Kong community and they are seen to have great potential for developing 3-dimensional and high accuracy ubiquitous location based services, to support a varieties of location based services applications. ...
Chapter
Hong Kong is a highly urbanized city with a very complicated public transport system. Local residents and tourists rely heavily on public transport for everyday travelling. To assist people in making better use of the public transport system, a multi-modal public transport query and guiding LBS system for mobile users is developed. This system can automatically determine the mobile device position with cellular network positioning technology, and with the user-defined destination, optimal traveling routes in terms of shortest travelling time and lowest fare are suggested. An overview of this system with emphasis on the system user interface, integration of GIS and mobile positioning technology are discussed in this paper.
... They also have a fast response time and the cost effectiveness, life time and low maintenance are some important benefits (using passive tags) because no batteries are needed. Some examples are given in Miller et al. (2006), Ni, Liu, Cho, and Patil (2003) Patil, Munson, Wood, and Cole (2005). ...
Article
Location awareness is a key issue to improve the development of autonomous entities that are embedded into ubiquitous computing environments. GPS seems to be the best solution to develop outdoor location systems, but the performance of these systems is not good enough to locate objects or humans within indoor environments, mainly if accuracy and precision are required. In this article we propose the use of a cheap and reliable technology as RFID to develop a passive RFID-based indoor location system that is able to accurately locate autonomous entities, such as robots and people, within a defined surface. This system is applied to solve the robot tracking problem. We include the evaluation of the proposal by comparing our system technology performance with other alternatives built on different technologies (Wi-Fi, Bluetooth, IrDA, ultrasound, etc.). We have also performed a location awareness proof concept test to analyze the viability of the approach.
... This scenario implies the wider availability of rfid tagging so that at any one time a reader would be within range to many tags. This approach can be implemented in different ways, for example [84] uses a mobile robot and cross-calibration using WLAN signal strength measurements to improve the accuracy of both systems. However, the viability of this approach depends heavily on the density of tags and despite early promising results the method requires further validation. ...
Article
Full-text available
rfid has already found its way into a variety of large scale applications and arguably it is already one of the most successful technologies in the history of computing. Beyond doubt, rfid is an effective automatic identification technology for a variety of objects including natural, manufactured and handmade artifacts; humans and other species; locations; and increasingly media content and mobile services. In this survey we consider developments towards establishing rfid as the cost-effective technical solution for the development of open, shared, universal pervasive computing infrastructures and look ahead to its future. In particular, we discuss the ingredients of current large scale applications; the role of network services to provide complete systems; privacy and security implications; and how rfid is helping prototype emerging pervasive computing applications. We conclude by identifying common trends in the new applications of rfid and ask questions related to sustainable universal deployment of this technology.
... O BTAINING accurate location information is important for many applications, including navigation tools for humans and robots, building mapping, interactive games, resource discovery, asset tracking and location-aware sensor networking [1], [2], [3], [4], [5], [6], [7]. GPS works well outdoors, but fails in indoor environments due to signal attenuation by the building fabric [8]. ...
Conference Paper
Full-text available
This paper presents a novel algorithm for determining the 3D location of a Mobile Tag (MT) using wireless Base Stations (BSs) and Ultra Wide Band (UWB) one-way signaling. The algorithm is designed for low power, rapid deployment applications in which the BSs are independent, wireless UWB transceivers located at known positions and the tags are receive-only or transmit-only UWB mobile units. The algorithm utilizes multi-BS time synchronization and hybrid Time Difference of Arrival-Time of Flight (TDoA-ToF) localization to achieve high accuracy tag localization. The algorithm consists of two concurrent tasks. In task I, the BSs exploit periodic inter-BS transmissions to obtain high accuracy multi-BS time synchronization. In task II, a hybrid TDOA-TOF algorithm is used to determine the location of the MT. The algorithm is based on timestamping, or control, of packet Time of Emission (ToE) and estimation of the packet Time of Arrival (ToA). As such, the method is appropriate for use with, but not limited to, IEEE 802.15.4a UWB. In simulations assuming a typical 2 cm standard deviation in ToA estimation error the proposed algorithm was found to provide a RMS error of 2.1 ps and 4.8*10-6 ppm for time offset and crystal clock offset between BSs respectively; and a RMS error in MT location estimation of 2.2 cm; which is 36% better accuracy than the conventional TDoA method.
... LANDMARC [9] is an active RFID calibrated positioning system in which fixed RFID tags are used to serve as reference points. BlueBoT [10] system combines passive RFID technology together with Wi-Fi based (802.11b) system to enable a periodic asset-location sweep. ...
Conference Paper
Full-text available
Recent trend have shown the wide spread of RFID application in various areas in line with the realization of low cost RFID tags and increasing worldwide commonality and compatibility. One of the important RFID applications is in object tracking and positioning due to its ability of high speed contactless identification in non-line of sight (NLOS) shared medium. This paper proposes a highly accurate square grid based RFID positioning and tracking technique mainly for use in indoor. It involves design of square grid RFID reader antenna network and position calculation using diffusion algorithm. Square grid reader antenna network presents the solution of placement pattern of RFID reader antennas, hence optimal number of required RFID reader antennas and coverage can be achieved. Diffusion algorithm [12] is a means of exchanging information over short range in estimating RFID tag position by using distance information between reader and tag. The proposed square grid tracking and positioning method is evaluated and compared with the existing positioning method such as Wi-Fi based positioning method and BlueBoT system. The obtained results indicate that the proposed method can achieve average positioning error below 1m and in some cases error as low as 0.3m can be reached.
... There are many factors that may affect the signal strength information [7]. Hence, the position is calculated in this paper using statistical averages algorithm [13] which maintains tracking solution with high degree of accuracy and does not depend on the received signal strength information. This algorithm computes the location coordinates of the tagged object by statistical average of the reader antenna's location when it detects any tag. ...
Conference Paper
Full-text available
This paper has investigated a new way of positioning system based on geometric grid covering algorithm that uses passive RFID technology for tracking objects inside buildings. This study involves design of RFID reader antenna network which focuses on placing reader antennas on a grid to cover all the tags distributed at two dimensional planes and finally, position obtained using statistical averages algorithm. The formulation of this low density reader antenna network can assist in minimizing the required number of reader antennas to cover a given set of tags. The proposed prototype system presents the solution of placement pattern of RFID reader antennas, gives less complicated mathematical calculation, and is able to provide a high degree of accuracy. The obtained results show that the proposed method can achieve better positioning accuracy as compared to existing positioning system and in some cases accuracy improvement of about 50% can be reached.
... In general, the routing algorithm based on ZigBee protocol should satisfy three conditions: first, [11,12] make full use of network bandwidth and reduce the network overhead as much as possible under the conditions permit; second, in the premise of ensuring the effectiveness of information transmission, improve routing efficiency, reduce the energy consumption of network nodes; third, with load balancing the effective strategies of avoiding node overload and cause because of node failure, thus affecting the overall performance of the network. ...
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Modern markets have put intensive effort on commodity arrangement in order to satisfy the consumer demands on commodity purchase. However, most markets do not provide satisfactory shopping services to customers. For instance, without a customized shopping recommendation for each individual customer, consumers have to spend a lot of time for commodity selection. Furthermore, most large-spaced markets merely utilize signs in front the aisles of specific commodity areas to direct consumers, which cannot provide an accurate guidance for commodity search. Therefore, regarding the shopping services of a modern market, this research develops a customized commodity recommendation algorithm and a shopping route determination and guiding algorithm. Based on the proposed algorithms, a Shopping Service System (3S-System) is established by integrating the RFID technology. Considering the consumer demands, consumer shopping preferences and market promotion plans, this research proposes an integrated, heuristic methodology to provide a customized purchase list, route recommendation and real-time direction guiding for consumer shopping. Moreover, based on the proposed methodology, a Shopping Service System (3S-System) is established, and a simulated market is created in order to verify the feasibility of the proposed model. The verification results show that the system can offer customers appropriate shopping route recommendation in a short time and could achieve real-time guiding. As a whole, this research provides a methodology and system to provide effective shopping services for consumers and as a result the shopping service quality of modern markets can be enhanced and the sales volume of commodities can be increased.
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Effective monitoring of personnel movements, material locations, and construction equipment has always been a topic of concern in construction management. Radio Frequency Identification (RFID) technology has been proven to increase efficiency for staff and materials management. The objective of this study is to develop a Three-Dimensional (3D) location sensing algorithm using RFID technology to analyze the possible location of objects. To achieve this goal, this research first establishes an indoor wireless sensing network to collect Received Signal Strength Indication (RSSI). The distance between the antenna and target tag is calculated based on RSSI. The gradient decent method is then used to calculate the location of the electronic tag. The feasibility of this 3D positioning algorithm is verified using a real case. The experiment proves that the location sensing algorithm established in this study can gradually approach the actual location of the target tag. This research is one of the first studies for 3D location sensing with RFID application in the construction industry. The proposed RFID 3D sensing algorithm can be used to assist construction managers in locating the positions of relevant personnel, equipment, apparatus and materials, enhancing management efficiency and safety.
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Purpose – This paper aims to propose the idea of developing an automatic Radio Frequency Identification (RFID)-based system for library search and to examine the existing literature to determine whether current technology and developed RFID-based systems are helpful for building that. To fully understand its key points, adoptions, risks, and benefits, the fundamentals of radio frequency are to be identified and reviewed. Some applications of radio frequency identification in library systems and various industries are to be briefly discussed and four related cases reviewed. Design/methodology/approach – The paper identifies key benefits and risks of radio frequency identification through review of library literature and case studies. For this purpose, four cases are reviewed from the entire industry and then key features of those cases are matched with the requirements of the big pictures' RFID-based system to determine the current level of the RFID-based system development. Findings – To make library systems functional and successfully operational RFID solutions can be used to reduce operating costs through decreasing the labor costs, enhancing automation, improving tracking and tracing, and preventing the loss of materials under any circumstances. Originality/value – The proposed automated RFID-based system is a novel idea by itself. Owing to the fact that better management of books and materials becomes possible, materials are not lost, theft is avoided, and patrons are served on time and correctly.
Conference Paper
The recent development of economical high-capacity RFID cards has opened up a new opportunity for stigmergic robotic swarms. Through these cards, robotic agents can dynamically exchange more complex, logical information, such as the whole set of their behavioral rules or ldquoculturerdquo. To the best of our knowledge, this opportunity has not been explored in swarm robotics and other collective robotics communities. We have developed a prototypical robotic swarm system comprised of 8 low-cost OPEN-ROBOTs with the ability to avoid obstacles and exchange information with low-capacity RFID cards randomly distributed in an environment. To evaluate the effectiveness of our RFID-based cultural transmission technique, we created a realistic computer simulation to test the swarm's competence in mapping a virtual multi-room house covered with 80 low-capacity RFID cards in under one hour. By increasing the probability that a robot adopts a random exploration behavior different from one ldquomarkedrdquo on a card, the swarm is able to cover more of an environment with higher consistency between trials. This result indicates that encouraging diversity among agents supports robust emergent behavior and lays the groundwork for future experiments with higher-capacity RFID cards.
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In recent years, the use of radio frequency identification (RFID) within supply chain management has received considerable attention. A significant upfront investment together with uncertain return on investment, however, remain impediments to deployments of RFID systems. This paper proposes a novel approach to analyze the potential benefits of RFID systems. We suggest deployment strategies that determine an optimal location of RFID within a supply chain network. The resulting models can be used to evaluate the value of information with respect to item losses. In addition, we discuss methods for solving the resulting large-scale optimization problems, and analyze how various system characteristics impact optimal deployment strategies as well as the overall RFID benefits.
Article
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009. Includes bibliographical references (p. 52-55). The use of RFID technology in libraries has increased to the point where it is now the centerpiece of emerging automated self-checkout, return, and theft detection systems. With the external borders of the library secure, focus has shifted to improve the internal state of a library's collection, which is subjected daily to use and abuse by library patrons. In this thesis I present BookBot, a robot equipped with RFID readers, that automates the otherwise manual shelf-reading process and helps librarians keep their database in sync with the library's physical inventory. Experiments on single shelves and entire bookcases confirm that this robot-assisted approach to inventory management can not only detect misplaced books reliably, but accurately determine the order of the books on the shelves and even localize the coordinates of each book to within a few centimeters, enabling both the librarian and the user to reach a state of Enlightened Shelf Awareness. by Isaac M. Ehrenberg. S.M.
Chapter
Stigmergy has long been studied and recognized as an effective system for selforganization among social insects. Through the use of chemical agents known as pheromones, insect colonies are capable of complex collective behavior often beyond the scope of an individual agent. In an effort to develop human-made systems with the same robustness, scientists have created artificial analogues of pheromone-based stigmergy, but these systems often suffer from scalability and complexity issues due to the problems associated with mimicking the physics of pheromone diffusion.
Article
The leeway of robots in the Supply chain industry is gleaming. Creating a marketplace demand will keep on urging automation in SCM/robots sellers to enhance acceleration and carry propelled usefulness to the supply chain. Robotic system solution/arrangements convey an encouragement for patrons in the dissemination, warehousing, and assembling parts via computerizing cross-process-docking station, lay line-side conveyance, renewal, sorting case-picking, kitting, products to-individual, individual to-products, and larger than average/non-standard stock keeping units transportation. While robots have truly been fabricated and conveyed to play out a particular procedure or capacity, the steady condition of advancement in mechanical improvement will develop here. Robots have largely been removed physical manpower, performing practice and rigorous assignments. Such apprehensions are triggered by means of talented technologies with the aim of automate substantial tasks via robotics, intellectual tasks via artificial Intelligence, cognitive computing, and logistics work, transportation works, consumer repair/service jobs with the purpose of assortment from personal-help centre to big sized container terminals. Robots are not only a fascinating innovation for science ventures. In this review, the acceleration of robot in supply chain has been discussed and an attempt has been made to understand the advantage and application of the robot in the industries.
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The architecture of RFID system substituting for barcode system in the production or manufacturing field is proposed in this paper. Take tobacco production process as an example. Through the reconstruction of the cigarettes sorting and stacking-transport system with RFID technology, higher production velocity and more expeditious cigarettes delivering stack by stack from ware-house have been achieved successfully. The technology may be brought to home appliances manufacturing sector for its high efficiency.
Chapter
In the past decades, warehouse management system has been generally considered as a bottleneck in the whole organization of business. According to the literature, the cost of order picking activity is the major expense of operating in a typical warehouse due to the introduction of new operating programs such as Just-In-Time, cycle time reduction and quick response. For these reasons, we propose a simulated RFID-based order picking system to improve efficiency of operating in the warehouse, especially deal with the important rush orders. Furthermore, a location sensing prototype system with the application of RFID and back-propagation algorithm for locating objects is also presented in this research. The main advantage of applying RFID sensing system is to enhance efficiency of operating via novel dispatching way based on instantaneous message advised from optimize route when the real-time information for a picker is received.
Article
Full-text available
Maintaining an accurate and up-to-date inventory of one's assets is a labor-intensive, tedious, and costly oper-ation. To ease this difficult but important task, we design and implement a mobile asset tracking system for automatically generating an inventory by snapping photos of the assets with a smartphone. Since smartphones are becoming ubiquitous, construction and deployment of our inventory management solution is simple and cost-effective. Automatic asset recognition is achieved by first segmenting individual assets out of the query photo and then performing bag-of-visual-features (BoVF) image matching on the segmented regions. The smartphone's sensor readings, such as digital compass and accelerometer measurements, can be used to determine the location of each asset, and this location information is stored in the inventory for each recognized asset. As a special case study, we demonstrate a mobile book tracking system, where users snap photos of books stacked on bookshelves to generate a location-aware book inventory. It is shown that segmenting the book spines is very important for accurate feature-based image matching into a database of book spines. Segmentation also provides the exact orientation of each book spine, so more discriminative upright local features can be employed for improved recognition. This system's mobile client has been implemented for smartphones running the Symbian or Android operating systems. The client enables a user to snap a picture of a bookshelf and to subsequently view the recognized spines in the smartphone's viewfinder. Two different pose estimates, one from BoVF geometric matching and the other from segmentation boundaries, are both utilized to accurately draw the boundary of each spine in the viewfinder for easy visualization. The BoVF representation also allows matching each photo of a bookshelf rack against a photo of the entire bookshelf, and the resulting feature matches are used in conjunction with the smartphone's orientation sensors to determine the exact location of each book.
Chapter
IntroductionRFID technologyRFID potential in the agrifood supply chainRFID and traceability processes in the agrifood supply chainRFID and quality control management processesRFID and manufacturing processesRFID and warehouse and distribution processesRFID and asset management processesRFID and point of sales processesConclusions References
Book
Drawing on the authors’ more than six years of R&D in location-based information systems (LBIS) as well as their participation in defining the Java ME Location API 2.0, Location-Based Information Systems: Developing Real-Time Tracking Applications provides information and examples for creating real-time LBIS based on GPS-enabled cellular phones. Each chapter presents a general real-time tracking system example that can be easily adapted to target any application domain and that can incorporate other sensor data to make the system "participatory sensing" or "human-centric sensing." The book covers all of the components needed to develop an LBIS. It discusses cellular phone programming using the Java ME platform, positioning technologies, databases and spatial databases, communications, client- and server-side data processing, and real-time data visualization via Google Maps and Google Earth. Using freely available software, the authors include many code examples and detailed instructions for building your own system and setting up your entire development environment. Web Resource A companion website at www.csee.usf.edu/~labrador/LBIS provides additional information and supporting material. It contains all of the software packages and applications used in the text as well as PowerPoint slides and laboratory examples. Although LBIS applications are still in the beginning stages, they have the potential to transform our daily lives, from warning us about possible health problems to monitoring pollution levels around us. Exploring this novel technology, Location-Based Information Systems describes the technical components needed to create location-based services with an emphasis on nonproprietary, freely available solutions that work across different technologies and platforms.
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Full-text available
We propose a new concept, called "real world crawling", in which intelligent mobile sensors completely recognize environments by actively gathering information in those environments and integrating that information on the basis of location. First we locate objects by widely and roughly scanning the entire environment with these mobile sensors, and we check the objects in detail by moving the sensors to find out exactly what and where they are. We focused on the automation of inventory counting with barcodes as an application of our concept. We developed "a barcode reading robot" which autonomously moved in a warehouse. It located and read barcode ID tags using a camera and a barcode reader while moving. However, motion blurs caused by the robot's translational motion made it difficult to recognize the barcodes. Because of the high computational cost of image deblurring software, we used the pan rotation of the camera to reduce these blurs. We derived the appropriate pan rotation velocity from the robot's translational velocity and from the distance to the surfaces of barcoded boxes. We verified the effectiveness of our method in an experimental test.
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Full-text available
Recently the wireless location systems become an important issue for all libraries. RFID is an innovative automated library system for automatic identification and pathway of library material. An automated library with the support of RFID technology would be a “self service center for library. Utilizing RFID-tagged book retrieval is a purpose advance for the library search system namely Library Book Exhausting Retrieval Supporting System. This paper presents the development of this utilizing RFID implementation flow and as well as the laboratory scale system structure. The book list mode offers a corresponding list of the bookshelves and the misplaced books regularly for a librarian to localize all misplaced books in the wrong bookshelves and will prove immediate and long term benefits to library in traceability and security.
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RFID has been used as an identification tool that substitutes for bar codes. Its areas of application are increasing due to its suitability in ubiquitous environment. In this paper, first, we review various aspects of RFID, including standards, characteristics, and relationships with wireless sensor networks. Then, we review the technical aspects of RFID and its areas of application, e.g., supply chain management (SCM) and manufacturing since 2005. SCM, in which RFIDs can shorten lead time and ensure the quality of products, is one of the most active application areas. Manufacturing is a relatively new area for RFID applications, but it is believed that it can enhance the productivity and the reliability of the products. Also, the authors suggest research issues and limitations of RFID, as well as possible application areas related to marine engineering.
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Managing Information Technology (IT) assets in data centers is a time consuming and error prone process. IT personnel typically identify misplaced assets manually by cross checking and visually inspecting assets. An automated way of keeping track of assets using portable devices reduces human error and improves productivity. The proposed asset management application on the tablet captures images of assets and searches an annotated database to identify the asset. Matching performance and response time of asset matching is evaluated using three different image feature descriptors. Methods to reduce feature extraction and matching complexity were developed. Performance and accuracy tradeoffs were studied, domain specific problems were identified, and optimizations for portable platforms were made. The results show that the proposed methods reduce complexity of asset matching by 67 % when compared to the matching process using standard image feature descriptors.
Book
Full-text available
UsiXML'2011, the 2nd International Workshop on User Interface eXtensible Markup Language, was held in Lisbon, Portugal (September 6, 2011) during the 13th IFIP TC13 International Conference on Human-Computer Interaction Interact'2011 (Lisbon, September 5-9, 2011).age. This edition is devoted to software support for any User Interface Description Language. A User Interface Description Language (UIDL) is a formal language used in Human-Computer Interaction (HCI) in order to describe a particular user interface independently of any implementation. Considerable research effort has been devoted to defining various meta-models in order to rigorously define the semantics of such a UIDL. These meta-models adhere to the principle of separation of concerns. Any aspect of concern should univocally fall into one of the following meta-models: context of use (user, platform, environment), task, domain, abstract user interface, concrete user interface, usability (including accessibility), workflow, organization, evolution, program, transformation, and mapping. Not all these meta-models should be used concurrently, but may be manipulated during different steps of a user interface development method. In order to support this kind of development method, software is required throughout the user interface development life cycle in order to create, edit, check models that are compliant with these meta-models and to produce user interfaces out of these methods.
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In recent years, the position location applications have increasingly. In this paper, we will use multiple Back-Propagation neural networks with genetic algorithm (GA) for a radio frequency identification (RFID) indoor location system to provide location services named indoor location with multiple neural networks and genetic algorithms (ILMNGA). In Section 1, we collect received signal strength (RSS) information from reference points to train the neural network models. In Section 2, genetic algorithm (GA) is used to find the weight of each neural network based on the performance of each neural network. Finally, we input the RSS information of each tracking object into the model that will provide the location of tracking objects based on the RSS information. The location will be integrated using the weights produced by the GA. The experiment conducted our methodology can provide better accuracy than a single neural network.
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In this paper, complete object searching and operating scheme for a service robot in complex indoor environments is presented to realize its human-centered active service in an intelligent space. The scheme is described as below. Firstly, the rough localization for an object is realized using the probability model for radio frequency identification(RFID) antenna's recognition scope and the Bayes Rule. Then, with the aid of an artificial object mark based recognition approach for multi-type objects, the quick and efficient localization based on monocular vision is realized using the system model of robot and the object's features. Finally, a position based visual servoing control law under eye-gaze constraint is used to realize object grasp and delivery. An object rearching and operating system was designed and implemented according the scheme. The system not only makes full use of the advantages of RFID in the field of object localization in a large scale, but also efficiently utilizes the rich information provided by the robot vision, and can accurately recognize the multi-type objects in complex indoor environments. The system has the high accuracy, well stability and high positioning precision. Besides, it can solve the occlusion problems to some extent. Now, the system has been successfully applied to the active service in intelligent space.
Conference Paper
Recently, the wireless location system become an important issue. However, the previous location mechanisms were seldom proposed for locating applications in library. In this paper, we present a smart Book-LOCating System called BLOCS with two location modes using RFID technology -single book mode and book list mode. The single book mode provides users to find the bookshelf containing the desired book which was misplaced. The book list mode offers a corresponding list of the bookshelves and the misplaced books regularly for a librarian to localize all misplaced books in the wrong bookshelves. The simulation results show that the locating accuracies of the single book mode and the book list mode are more than 90% and 85%, respectively.
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Full-text available
Growing convergence among mobile computing devices and embedded technology sparks the development and deployment of “context-aware” applications, where location is the most essential context. In this paper we present LANDMARC, a location sensing prototype system that uses Radio Frequency Identification (RFID) technology for locating objects inside buildings. The major advantage of LANDMARC is that it improves the overall accuracy of locating objects by utilizing the concept of reference tags. Based on experimental analysis, we demonstrate that active RFID is a viable and cost-effective candidate for indoor location sensing. Although RFID is not designed for indoor location sensing, we point out three major features that should be added to make RFID technologies competitive in this new and growing market.
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Full-text available
Providing a reliable technology and architecture for determining the location of real world objects and people will undoubtedly enable applications, customization, and inference not currently possible. This paper documents the creation of SpotON, a new tagging technology for three dimensional location sensing based on radio signal strength analysis. Although there are many aspects to the topic of location sensing and several of them will be briefly discussed, this paper is primarily concerned with the hardware and embedded system development of such a system.
Conference Paper
Full-text available
Angle of arrival (AOA) has previously been used for outdoor positioning in aircraft navigation and for services like E911. For indoor positioning, the best schemes to date rely either on extensive infrastructure, or on sampling of the signal strength on a dense grid, which is subject to changes in the environment, like furniture, elevators, or people. We present an indoor positioning architecture that does not require a signal strength map, simply requiring the placement of special VOR base stations (VORBA). While our incipient realization of the AOA using 802.11 uses a base station with a revolving directional antenna, a non mechanical implementation would yield comparable performance, even with quantized angles. Performance of positioning with VOR base stations is evaluated though experimentation, simulation, and theoretical analysis.
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Full-text available
sent out by a central facility that addresses a particular receiver unit (beeper) and produces an audible signal. In addition, it may display a number to which the called-party should phone back (some systems allow a vocal message to be conveyed about the call-back number). It is then up to the recipient to use the conventional telephone system to call-back confirming the signal and determine the required action. Although useful in practice there are still circumstances where it is not ideal. For instance, if the called party does not reply the controller has no idea if they: 1) are in an area where the signal does not penetrate 2) have been completely out of the area for some time 3) have been too busy to reply or 4) have misheard or misread the call-back number. Moreover, in the case where there are a number of people who could respond to a crisis situation, it is not known which one is the nearest to the crisis and therefore the most suitable to contact. A `tagging system' does not
Conference Paper
Full-text available
Growing convergence among mobile computing devices and embedded technology sparks the development and deployment of "context-aware" applications, where location is the most essential context. We present LANDMARC, a location sensing prototype system that uses Radio Frequency Identification (RFID) technology for locating objects inside buildings. The major advantage of LANDMARC is that it improves the overall accuracy of locating objects by utilizing the concept of reference tags. Based on experimental analysis, we demonstrate that active RFID is a viable and cost-effective candidate for indoor location sensing. Although RFID is not designed for indoor location sensing, we point out three major features that should be added to make RFID technologies competitive in this new and growing market.
Conference Paper
Full-text available
We present a WLAN location determination technique, the Joint Clustering technique, that uses: (1) signal strength probability distributions to address the noisy wireless channel, and (2) clustering of locations to reduce the computational cost of searching the radio map. The Joint Clustering technique reduces computational cost by more than an order of magnitude, compared to the current state of the art techniques, allowing non-centralized implementation on mobile clients. Results from 802.11-equipped iPAQ implementations show that the new technique gives user location to within 7 feet with over 90% accuracy.
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Full-text available
The use of bayesian-filter technology as a statistical tool in order to help manage measurement uncertainity and to perform multisensor fusion and identity estimation, is discussed. The fusion of sensor data from ultrasound and infrared tags and combining of high-resolution location information from asynchronous laser range finders with low-resolution location sensors that provide information is also discussed. Bayes filters probabilistically estimate a dynamic system's state from noisy observations. The identity-estimation problem is solved by using a combination of particle filters and Kalman filters.
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Full-text available
We present a WLAN location determination technique, the Joint Clustering technique, that uses (1) signal strength probability distributions to address the noisy wireless channel, and (2) clustering of locations to reduce the computational cost of searching the radio map. The Joint Clustering technique reduces computational cost by more than an order of magnitude, compared to the current state of the art techniques, allowing non-centralized implementation on mobile clients. Results from 802.11-equipped iPAQ implementations show that the new technique gives user location to within 7 feet with over 90% accuracy.
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Full-text available
In this paper, techniques and algorithms developed in the framework of statistical learning theory are analyzed and applied to the problem of determining the location of a wireless device by measuring the signal strengths from a set of access points (location fingerprinting). Statistical Learning Theory provides a rich theoretical basis for the development of models starting from a set of examples. Signal strength measurement is part of the normal operating mode of wireless equipment, in particular Wi-Fi, so that no custom hardware is required.
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The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF) based system for locating and tracking users inside buildings. RADAR operates by recording and processing signal strength information at multiple base stations positioned to provide overlapping coverage in the area of interest. It combines empirical measurements with signal propagation modeling to determine user location and thereby enable location-aware services and applications. We present experimental results that demonstrate the ability of RADAR to estimate user location with a high degree of accuracy.
Article
Determining the location of a mobile computer user has several applications. We have developed and demonstrated a person locator using the wireless network infrastructure at Carnegie Mellon University to accomplish this task. A user's location can be determined both indoors and out- doors while on campus, and at a higher resolution than the Global Positioning System. The system requires a minimum of extra hardware but results in a high degree of accuracy.
Conference Paper
We demonstrate a system built using probabilistic techniques that allows for remarkably accurate localization across our entire office building using nothing more than the built-in signal intensity meter supplied by standard 802.11 cards. While prior systems have required significant investments of human labor to build a detailed signal map, we can train our system by spending less than one minute per office or region, walking around with a laptop and recording the observed signal intensities of our building's unmodified base stations. We actually collected over two minutes of data per office or region, about 28 man-hours of effort. Using less than half of this data to train the localizer, we can localize a user to the precise, correct location in over 95% of our attempts, across the entire building. Even in the most pathological cases, we almost never localize a user any more distant than to the neighboring office. A user can obtain this level of accuracy with only two or three signal intensity measurements, allowing for a high frame rate of localization results. Furthermore, with a brief calibration period, our system can be adapted to work with previously unknown user hardware. We present results demonstrating the robustness of our system against a variety of untrained time-varying phenomena, including the presence or absence of people in the building across the day. Our system is sufficiently robust to enable a variety of location-aware applications without requiring special-purpose hardware or complicated training and calibration procedures.
Conference Paper
The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF)-based system for locating and tracking users inside buildings. RADAR operates by recording and processing signal strength information at multiple base stations positioned to provide overlapping coverage in the area of interest. It combines empirical measurements with signal propagation modeling to determine user location and thereby enable location-aware services and applications. We present experimental results that demonstrate the ability of RADAR to estimate user location with a high degree of accuracy
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Global positioning system (GPS) is the most important gift of the Department of Defense to the civil world, perhaps with the exception of the Internet. Civil applications unforeseen by developers of the system are thriving and many more are on the way. Commerce in GPS equipment and services continues to grow rapidly and this success has created expectations and demands that the system was not designed to meet. In order to cope with these issues and understand the technology and applications of this global resource, various aspects GPS: the satellites; receivers; positioning algorithms; and several important applications; are discussed.
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Emerging mobile computing applications often need to know where things are physically located. To meet this need, many di#erent location systems and technologies have been developed. In this paper we present a the basic techniques used for location-sensing, describe a taxonomy of location system properties, present a survey of research and commercial location systems that define the field, show how the taxonomy can be used to evaluate location-sensing systems, and o#er suggestions for future research. It is our hope that this paper is a useful reference for researchers and location-aware application builders alike for understanding and evaluating the many options in this domain. 1
A Comparison of RF Tag Location Products for Real-World Applications
  • P Steggles
  • J Cadman
P. Steggles and J. Cadman, "A Comparison of RF Tag Location Products for Real-World Applications," Ubisense March 2004.http://www.ubisense.net/technology/files/A comparison of RF Tag location products for real world applications -March 2004.pdf
The Bat Ultrasonic Location System
  • Aeroscout
AeroScout (formally BlueSoft)."http://www.aeroscout.com/ [2] "The Bat Ultrasonic Location System."http://www.uk.research.att.com/bat/