Research of real-time kinematic satellite positioning technology (RTK) for monitoring landslide deformations

Introduction. The article deals with the issues of geodetic control of displacements of the observation station’s working benchmarks on landslide slopes. The authors assume that by using Real-Time Kinematic (RTK) satellite positioning technology to determine the displacements of the observation station’s working benchmarks fixed in the landslide body, it is possible to achieve the required accuracy according to the Code of Practice 420.1325800.2018. According to the results of the experiments, it is possible to achieve the required accuracy of observations using RTK technology by exceeding the observation period to 2 minutes (which is equivalent to achieving 120 epochs at a measurement frequency of 1 Hz), limiting the distance of the GNSS vector (GNSS – Global Navigation Satellite Systems) to the value of 2 km, and using recievers that supports at least 4 GNSS systems. Research objective. The objective of the present study is to extend the existing body of knowledge concerning RTK satellite positioning technology, with a particular focus on its application in the observation of the displacements of the reference benchmarks fixed within the body of a landslide. RTK technology has been extensively utilized in various domains. However, there are still questions regarding the allowable parameters to be adjusted in the mission, including the required duration of the observation session of each of the reporters, the allowable length of the GNSS vector from the base station to the rover, preferred number of GNSS systems, the allowable value of ‘dilution of precision’ (DOP), and the preferred measurement mode: from a single base station or network mode. These parameters can influence the obtained result, that is why the research task is aimed at comparing these parameters with the requirements of regulatory documentation to the accuracy of observations of displacements of the observation station working benchmarks on landslides. Methods and materials. In order to investigate the RTK technology, a series of experiments were conducted in order to obtain the root mean square errors (RMSE) of determining the displacements of the observation station working benchmarks by RTK technology with different observation session durations, GNSS vector lengths from the base station to the rover, and the number of GNSS systems. For this purpose, a deformation process was modeled using dowels fixed in hard pavement, and the distances and exceedances between them were determined by methods many times more accurate than those of satellite determinations. These distances and elevations were subsequently used as a reference for comparison with the distances and elevations obtained from GNSS RTK observations. Results. The classification of conditions and parameters of observations is presented on the basis of the research conducted. This classification is according to the achieved accuracy of the determination of displacements of the observation station working benchmarks on the landslide by RTK technology. Conclusions. Based on the experimental results, we can conclude that the application of RTK technology is feasible for observations of landform displacements on a landslide. In order to achieve the required accuracy, it is necessary to use increased observation sessions up to 2 minutes, which is equivalent to measurements at the number of epochs equal to 120 with a measurement frequency of 1 Hz. The length of the GNSS vector from the base station to the rover should not exceed 2 km. GNSS receivers supporting at least 4 GNSS systems should also be used.