Simulation case study of displacement monitoring using network derived positioning

Abstract

Network-based real-time kinematic (NRTK) GNSS (Global NavigationSatellite System) is among the most commonly used surveying technique in many countries for various applications that requires a single GNSS receiver. The main principle of this system is to generate reliable error models that can mitigate dispersive (e.g. ionospheric delay) and non-dispersive (e.g. tropospheric delay and orbit bias) errors, which are the main sources of the degradation of positioning accuracy. In this study, the performance of NRTK positioning for deformation and landslide monitoring is investigated using a simulation apparatus. For this purpose, 20 simulated two-dimensional and vertical displacements are conducted within a two-month period in 2019. The 24-h NRTK data with 1-s sampling intervals are obtained using a CHC N72 GNSS reference receiver for each displacement. The 24-h NRTK data are mutually subdivided into 12-, 6-, 3-and 1-h non-overlapping sessions to investigate the effect of observation time on monitoring displacement performance. Two filtering methodsnamely, averaging the raw observations and averaging the observations derived from Kalman filteringare chosen for each session. The displacements obtained from the filtered NRTK observations are compared to the simulated (true) displacements. Another experiment is carried out to monitor the displacement in real time using first-order low-pass and moving-average filters. The NRTK data are collected during the displacement for a real-time experiment. The results of the experiments indicate that 1-sigma horizontal and vertical Root Mean Square errors (RMSEs) of displacements between the filtered NRTK data and true displacements are determined to be 1.5 and 5.4 mm, respectively, using 24-h data. The results also suggest that no significant difference is observed between the filtering methods for most of the points. The RMSE of the two-dimensional displacement direction between the azimuth angle derived from the filtered NRTK data and the azimuth angle of true direction is found to be 15 for 3 mm displacement using 24-h data. For detecting the displacements visually in real time, the minimum magnitude of displacements needs to be 7 mm and 10 mm for the horizontal and vertical components, respectively, to distinguish the displacements from the noise.

Structural health monitoring of inland navigation structures and ports: a review on developments and challenges

“…Its accuracy is 5-10 mm for horizontal (i.e., on the plane of Earth's surface) displacements; however, due to the high noise profile, real-time vertical (i.e., in the zenith) measurements are challenging. 129 It requires the installation of single or multiple GPS antennas in the area of monitoring. Researchers have attempted to apply GPS monitoring for spatial structures such as coastal dikes, 91 breakwaters, 130 embankments.…”

Investigation of lane-level GNSS positioning of vehicle in urban area

“…In this regard, the authors of many works were faced with the task of using inexpensive receivers for high precision GNSS positioning for various applications. For example, the authors of [20,21] consider the possibility of using low-cost GNSS receiver for geodetic applications and geomatics, in low-cost GNSS receivers for local monitoring for detecting displacements [22] and in [23] the subject of research was the implementation of local monitoring of displacement, for example, landslides, using GNSS positioning with low-cost GNSS receiver. Thus, in this paper the task of studying the possibility of using a smartphone with a standard single frequency navigation receiver to determine the location of the vehicle on the lane level with an accuracy of 1-3 meters.…”