Abstract
This paper presents the displacement monitoring system named "GPS wireless sensor network". This system employs a low cost L1 GPS (Global Positioning System) receiver and wireless sensor network. Low cost sensor node and cable-less system enable dense deployment of observation points. In this research, it is required to solve the trade-off between energy consumption and accuracy of displacement measurements. Measuring continuous data and applying a trend analysis or Kalman filter might yield high accuracy displacement estimation but also needs much energy dissipation. To solve the trade-off relationship, a data compression method and a static GPS positioning analysis method are newly developed and implemented in the system. In these methods, assumption of quasi-static displacement is taken into account. A prototype system is developed and experiments are conducted in a construction site and an ideal condition using the developed prototype. The experimental results show that the prototype works properly and is able to measure displacements in sub-centimeters accuracy.
