Positioning and tracking construction vehicles in highly dense urban areas and building construction sites

In this paper, we review previous radio frequency (RF)-related research in construction and further evaluate the pros and cons of several RF-based technologies including GPS, RFID, and Bluetooth. Particularly, we show the limitations of applying GPS for tracking construction vehicles in a highly dense urban area by conducting extensive field tests in Hong Kong. We then propose a continuous, all-location, real-time solution for tracking, positioning construction vehicles by integrating GPS with the vehicle navigation technology called "dead reckoning" (DR). DR automatically supplants GPS when GPS signals become unavailable or unreliable. To automatically calibrate positioning errors resulting from DR, road-side beacons can be placed at control points with well-defined coordinates. The beacon operates on the Bluetooth for establishing communication links with the in-vehicle navigation unit. In addition, the real-time location and status of a construction vehicle can be transmitted to the control center by the use of short message service over mobile phone networks. In the context of monitoring ready mixed concrete production and delivery processes on and off building sites situated within the urban environment of Hong Kong, we conducted extensive field trials of the vehicle navigation technologies for 12 months in 2005/06. The integrated vehicle tracking system is found reliable and accurate for recording key event times of the mixer truck under practical site conditions.