Research on positioning and tracking system of construction workers based on ZigBee

Zhang Zhen Yu School of Automation and Electrical Engineering, Zhejiang University of Science and Technology,

Hangzhou, Zhejiang, 310023, P.R.China carriezyq@gmail.com

ABSTRACT

This study is based on the ZigBee wireless sensor network technology to locate and track construction workers. By using ZigBee as a network element, the construction workers as a wireless sensor network of mobile nodes, the wireless sensor networks and construction workers are combined in organic enriched wireless sensor networks. This paper describes the ZigBee-based positioning and tracking system hardware design, including the CC2430 ZigBee modules based positioning sub-stations, base locator, mobile positioning devices and transmission interface circuit design, and ZigBee-based positioning and tracking system software design. An RSSI-based positioning technology of construction worker is then proposed. The positioning and tracking system of construction workers for construction site is given as an example, which demonstrates that it is obviously helpful to the management of construction site.

Keywords: ZigBee; Wireless sensor network; Positioning and tracking system; Construction workers

1. INTRODUCTION Satellite navigation system is the most widely used as a navigation tool, such as GPS, GLONASS, GALILEO and

Compass system [1-2]. The success of outdoor positioning systems based on the GPS provides an incentive to the research and development of indoor positioning systems [3-4].

However, indoors, underground, high-rise buildings or vegetation block the satellite navigation system, so that it can not provide the navigation and positioning services [5]. Wireless sensor network is the current international concern, which combines sensor technology, wireless communication technology and computer technology, with information collection, transmission and processing capabilities. In a complex construction site environment, how to use new technology to create an effective management system becomes a big industry problem to be solved, such as cable restraints [6-9]. The application of a simple ZigBee protocol for wireless sensor networks is low-cost and low power [10].

This paper focuses on developing positioning and tracking system based on ZigBee and prescribes sensor network configurations that work well with position algorithms.

2. INTRODUCTION OF ZIGBEE ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios

based on the IEEE 802.15.4-2003 standard for wireless personal area networks [11]. The technology defined by the ZigBee specification [12] is intended to be simpler and less expensive. ZigBee is targeted at radio-frequency (RF) applications that require a low data rate, long battery life.

3. ARCHITECTURE OF POSITIONING AND TRACKING SYSTEM

3.1 Architecture of Wireless Sensor Network In a wireless sensor network, it always includes network coordinator, full-function devices, and reduced function

device. The gateway is used to receive messages and send commands to the gateway to control the entire system to finish the construction worker's individual information processing. Reference node is a known location in the static node, which can be its location by sending a packet to notify other nodes. Position node receives data from the reference node packet signal and the reference node location coordinates and the corresponding Received Signal Strength Indication (RSSI) value and into the positioning engine, which can then be read out by the positioning engine, the self-calculated position. The system architecture is shown in Figure 1.

Fourth International Conference on Digital Image Processing (ICDIP 2012), edited by Mohamed Othman,Sukumar Senthilkumar, Xie Yi, Proc. of SPIE Vol. 8334, 833442 · © 2012 SPIE

CCC code: 0277-786X/12/$18 · doi: 10.1117/12.968560

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Figure 1. System architecture of wireless sensor network based on ZigBee.

3.2 Hardware Design of Construction Workers Positioning System The system chose for the TI companies ZigBee chip CC2430, which can be achieved with the signal of the

transceiver functions, chip-rich, powerful, and its hardware structure is very simple, reliable.

1) Location sub-station module hardware design

Locate sub-stations serve as ZigBee coordinator, responsible for the initiation of ZigBee wireless networks and management of peacekeeping protection.

2) Reference module hardware design locator

It allows the ZigBee end device with its own connection to ZigBee networks for data forwarding, routing and other functions. Reference locator is widely distributed in construction sites.

3) Mobile terminal positioning module hardware design

Mobile positioning terminals are construction workers carry equipment, mobile positioning terminal through the ZigBee wireless module and the network connectivity and communications, to receive the upper broadcast information sent over the network, data processing server as the original location data.

4) Network topology design of construction workers positioning system

The establishment of a wireless network is based on the premise and chooses a reasonable network topology. We use mesh networks as a topological type.

The hardware design of construction workers positioning system is shown in Figure 2.

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Figture 2. The hardware design of construction workers positioning system

3.3 Software Design of Construction Workers Positioning System

Figure 3. The Software design of construction workers positioning system

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1) Initialize the network Network will be initialized after the first device initialization, and the first full-featured access to the network device

will be considered as main coordinator.

2) Update When a new node adds, network coordinator checks whether the number of nodes in the network exceeds the

maximum number of nodes, otherwise allows the node network.

3) Position calculation Location algorithm will be discussed in next section. The software design of construction workers positioning system is shown in Figure 3.

4. POSITIONING ALGORITHM OF CONSTRUCTION WORKERS BASED ON ZIGBEE

4.1 One Point Positioning Algorithm of Construction Workers based on ZigBee With known information of transmission power, received power measurement at the receiver node, the distance can

be calculated, with the use of theory or empirical propagation model signal propagation into the distance. For example, in free space away from the transmitter antenna d department received signal strength is given from the following formula (1) [12]:

Ld

GGPdP rtt

r 22

2

)4()(

π

λ= (1)

In which, Pt is the transmitter power, (W); Pr(d) is at a distance d department received power,(m); Gt, is the transmit antenna gain; Gr is the receive antenna gain; d is the distance, (m); L is the loss factor, with nothing to do with the transmission system; λ is the wavelength, (m).

4.2 Mul-points Positioning Algorithm of Construction Workers based on ZigBee Mul-points positioning algorithm of construction workers based on ZigBee is, as shown in Figure 4.

L1

L2

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Figure 4. Mul-points positioning algorithm.

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1. To calculate the distance L1, L2, L3 from R1, R2, R3 to the E1 point using the above algorithm;

2. Using sphere envelope obtained by R1, R2 and R3 for the center core, with L1, L2, L3 for the radius, the intersection point coordinates shall E1;

3. If there are multiple R points, with multiple measurements to find the coordinates of space points.

5. CONCLUSIONS This paper focuses on developing a positioning and tracking system and prescribes wireless sensor network

configurations that work well with position algorithms. This paper describes the ZigBee-based positioning and tracking system hardware design, and ZigBee-based positioning & tracking system software design. And it proposed positioning technology-based construction workers overall program tracking system. The positioning and tracking system of construction workers for construction site is given as an example, which demonstrates that it is helpful to the management of construction site.

6. ACKNOWLEDGEMENTS The authors are grateful for Zhejiang Provincial Education Department Foundation Projects (No.Y200908472).

7. REFERENCES [1]Wang H, Elson J, Girod L, Estrin D, Yao K. Target classification and localization in habitat monitoring, in:

Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2003), Hong Kong, April 2003, pp. 844–847.

[2]Son C, Yoo N, Kim W. Positioning System using Dynamic Location-convergence Adjustment Factor for Wireless LAN Infrastructures, In Proc. Sixth IEEE International Conference on Computer and Information Technology , IEEE Press, 2006, pp.233-237.

[3] Polastre J. Design and implementation of wireless sensor networks for habitat monitoring. Master’s thesis, University of California at Berkeley, Berkeley, CA, USA, 2003.

[4]Roos T, Myllymaki P, Tirri H, Misikangas P, Sievanen J. A probabilistic approach to WLAN user location estimation, International Journal of Wireless Information Networks,2002, vol. 9, no.3, pp.155‐164.

[5]Bahl P, Padmanabhan VN. RADAR. An in-building RF-based user location and tracking system, In: Proc of INFOCOM’2000, Tel Aviv, Israe1. 2000.

[6] Jin MH, Yu CH, La HR, et al. ZigBee positioning system for smart home application, Springe Berlin /Heidelberg,2007.

[7]Park C, Xie Q, Chou P, Shinozuka M, Duranode M. Wireless networked sensor for strutural health monitoring, IEEE Sensors, 2005, pp.277- 280.

[8] Karl H, Willig A. Protocols and architectures for wireless sensor networks, John-Wiley, New York ,2005. [9] Zhou R, Zhao CY, Fu LL, Chen A, Ye MQ. ZigBee-based vehicle access control system, in: Proc. 2010 Third

International Symposium on Intelligent Information Technology and Security Informatics, IEEE Press, 2010, pp.232-235.

[10] Wu L, Huang JL, Zhao ZH. ZigBee wireless location system research, in Proc. 2010 Second International Conference on Computer Modeling and Simulation, IEEE Press, 2010,vol.3, pp.316-320.

[11] http://en.wikipedia.org/wiki/ZigBee [12] ZigBee Alliance, ZigBee Specifications, http://www.zigbee.org.

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