Wireless sensing system for land movement monitoring and landslide detection

Abstract

Land deformation monitoring - one of the most important aspects of land­ slide monitoring - provides an important basis for identifying landslide risk. This project has developed a wireless sensing system for the early detection of landslide risk. The types of sensors used in current practice provide valuable data related to landslides, but incur costs in excess of US$300,000 per site - lim­iting their deployment to only very high-risk sites. Our system utilizes low cost GPS chips (around $100/sensor) and, powered by renewable energy, can be de­ployed in large numbers over areas that are potentially vulnerable to landslides. Each self-powered sensor records its location periodically and transmits the GPS data wirelessly to a remote collection centre for processing. Taking advantage of the similarity in wireless channel conditions of sensors within close proximity, we are able to accurately compute the relative displacement between any two neighbouring wireless sensors without the need to determine the exact locations of the sensors. Even under harsh conditions where only intermittent GPS data are available, we are able to achieve sub-centimetre accuracy based on our out­ door tests in New Zealand and also at the LuShan landslide site in Taiwan.