Evaluation of multi-GNSS high-rate relative positioning for monitoring dynamic structural movements in the urban environment

Abstract

Skyscrapers cause both limited sky-view and multipath error when using Global Navigation Satellite System (GNSS) measurements for monitoring structural movements. To reduce multipath errors, cutoff elevation angle can be set to a high value such as 30 À40. However, in the case of employing high cutoff elevation angles, the use of GPS only may not provide adequate positioning solutions. To overcome this problem, Galileo and GLONASS observations are combined with GPS observations. This study experimentally investigates the contribution of multi-GNSS for studying the effects of different cutoff elevation angles on the accuracy of high-rate GNSS results for detecting characteristics of dynamic motions for structural health monitoring (SHM). The filtration design, noise level and Signal-to-Noise Ratio (SNR) of high-rate GNSS measurements of GPS-only, GPS/Galileo, GPS/ GLONASS and GPS/GLONASS/Galileo are assessed for different cutoff elevation angles. The results demonstrate that the SNR of GNSS solutions for GPS/GLONASS and GPS/GLONASS/Galileo is the highest, which signifies their use in SHM. The accuracy of the dynamic movements of structures can be attained to 2 mm, on average, using multi-GNSS measurements even when using high cutoff elevation angles up to 40. The precision of GPS/GLONASS and GPS/GLONASS/Galileo systems with different cutoff elevation angles was high when referenced to LVDT.

An Evaluation of Optimization Algorithms for the Optimal Selection of GNSS Satellite Subsets

“…It can be observed that satellite selection becomes more challenging due to the size of the satellite subset, requiring higher parameter values and longer computation time. ABC showed better accuracy in selecting the optimum four GNSS satellite subset compared to the other sizes of satellite constellations (8,12,15) using the first two cases of parameter settings. This is due to the significant increase in the possible satellite combinations, which follows the increase in the number of satellites in the constellation (from 4 to 8, 12, and 15) (Figure 10).…”

“…GNSS satellite selection is the process of choosing the right GNSS satellite combination from the available GNSS satellites, aiming for better positioning quality with a lower computational load [10]. Various satellite selection criteria have been used for selecting satellites, including satellite elevation angle [11][12][13], satellite signal quality [14,15], GDOP [3,16,17], and weighted GDOP (WGDOP) [18,19]. Since GNSS accuracy is affected by both satellite geometry (i.e., GDOP) and satellite signal quality, the WGDOP, which is based on the satellite signal quality and the satellite geometry (GDOP), can be considered as the most suitable criterion for choosing satellites.…”

Investigation of Seismic Waveform and Co-seismic Displacements Based on GNSS Observations at CORS-TR Stations of Sofalaca-Şehitkamil Gaziantep (Mw:7.7) Earthquake on February 6, 2023 by Kinematic-Precise Point Positioning Technique

“…High-precision 3D position information from GNSS data plays an important role in detecting dynamic behavior on the fault [21]. In addition to GNSS seismology, many scientific studies have been carried out by integrating GNSS sensors in areas such as structural health monitoring for the detection of damage to buildings during earthquakes, early warning systems for the pre-detection of natural disasters such as earthquakes or tsunamis [22][23][24][25][26][27][28][29][30]. As a result of the northward movement of the Arabian Plate in the southeast of the East Anatolian Fault and the westward movement of the Anatolian Plate in the northwest, the studies carried out on this fault at different times are approximately 9±1mm/year [31], 5-8mm/ year [32,33], 10mm/year [4,34], 13mm/year [35], 11±3mm/year and 8mm/year [36], slip rates were calculated.…”

Evaluation of the single-frequency variometric approach based on low-cost GNSS observations and different satellite combinations for detecting short-term dynamic behaviors

“…Compared to geotechnical sensors such as accelerometers, the high-rate GNSS technique can directly detect displacements in the terrestrial reference frame, free of clipping or errors caused by integration or saturation [3]. It is worth mentioning here that the applications of detecting dynamic displacements in RT have been dominated by the RT kinematics (RTK) technique for almost two decades due to the high accuracy it provides [4][5][6]. However, the RTK technique requires an external GNSS infrastructure to ensure high accuracy, which will unavoidably render it unusable in the event of a possible mega-earthquake [7].…”