UAV-Enabled Installation of Wireless Sensors for Monitoring Inaccessible Cliffs and/or Emergencies

Monitoring is frequently used to study landslides (instabilities in soil and rock slopes) and to manage the risk when a focused mechanism is underway. To date, most of the so-called ‘geotechnical sensors’ and some surveying systems must be installed manually on the landslide body. In some scenarios this installation phase may imply a high risk for operators. To overcome these issues, we developed a simple system to install wireless sensors by means of Uncrewed Aerial Vehicle (UAV), which is presented in the paper along with the tests carried out. Concretely, we deployed several wireless precision tiltmeters able to acquire and transmit attitude readings using LOng-RAnge communication capability. The experiments were conducted in an area of paramount geomechanical and societal interest: the Montserrat massif (Barcelona, Spain), threatened by medium-to-large rockfalls. The procedure to attach the sensor to the UAV, release it, and glue it to the ground is described. Some of the results and issues that emerged are also presented and discussed. The tests show that the installation of sensors with UAVs can complement the monitoring techniques already available in the aforementioned special situations. The UAV-enabled deployment method should be considered as a means to speed up the availability of real-time data to monitor critical, hazardous situations.