Issue link: https://geospatial.trimble.com/en/resources/i/1482404
SATREPS project, financed by Japanese government, make it possible for the Kostanjek landslide to be equipped by densely spaced GNSS stations, comparing to other world- wide known landslide monitoring systems," Dr. Krkač said. "Geomatika Smolčak, together with Trimble Support helped to setup the GNSS monitoring system, and even now, five years after deployment of the solution, they help to solve different kinds of issues that arise related to data measurements and data transmission, which has been a tremendous asset." "T4D is an essential tool for monitoring the Kostanjek landslide movement," said Dr. Krkač. "It allows multiple GNSS processing options in parallel. For our project we used 60 minute and 24-hour post-processing intervals as well as 1 Hz RTK results. We also calculated precision of GNSS measurements and proved that they correspond to Trimble specifications which means that measurements at the Kostanjek landslide gives reliable data about antenna positions. Besides, daily monitoring of movement with high precision enable measurements of small displacements which is particularly important for analysis of slowly moving landslides, such as the Kostanjek landslide. "Among high temporal resolution of GNSS monitoring data, high spatial resolution of movement data is achieved by good coverage of the whole landslide area by 15 GNSS stations. Donation through The Trimble NetR9 receivers collect GNSS data and deliver it in real-time via wireless routers to Trimble 4D Control software, installed on an application server in a data center at the Faculty of Mining, Geology and Petroleum Engineering of the University of Zagreb. GNSS network is stable and average loss of data from particular GNSS station during monitoring period is only 3%, or analyzes the monitoring data in real- time and issues alarms automatically whenever the system detects movement. Trimble 4D Control is a very versatile monitoring software which is also perfect for the use in other monitoring applications such as mines, dams and construction related monitoring. In total, 15 Trimble NetR9 TI-2 GNSS reference stations with Zephyr Geodetic 2 GNSS antennas have been installed on site. Dr. Krkač explains that the Kostanjek landslide GNSS receivers are mounted on 4- meter-high poles with 1-meter-deep reinforced foundations. One GNSS reference station, located in a stable area approximately 7 kilometers (4.3 miles) south of the landslide, is used as a base station. In addition to the GNSS receivers the monitoring system also uses various geotechnical sensors such as long- and short-span extensometers, pore pressure gauges in boreholes, water level gauges in wells, and a weather station including a rain gauge. Figure 2. Trimble T4D Displacement Chart Trimble 4D Control and GNSS Provide Daily Monitoring Real-time Data Transmission I N D U S T R Y P R O D U C T W A T C H G I S R E S O U R C E S | S E P T E M B E R 2 0 1 8 2 3