scholarly journals Detection and Monitoring of Tunneling-Induced Riverbed Deformation Using GPS and BeiDou: A Case Study

2019 ◽  
Vol 9 (13) ◽  
pp. 2759 ◽  
Author(s):  
Wen Guo ◽  
Guoquan Wang ◽  
Yan Bao ◽  
Pengfei Li ◽  
Mingju Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Urban Areas ◽  
Ground Deformation ◽  
Base Station ◽  
Deformation Monitoring ◽  
Change Point Detection ◽  
Structural Deformation ◽  
Double Difference ◽  
Deformation Model

Shield tunneling under rivers often requires monitoring riverbed deformations in near real-time. However, it is challenging to measure riverbed deformation with conventional survey techniques. This study introduces a comprehensive method that uses the Global Positioning System (GPS) of the USA and the BeiDou navigation satellite system (BeiDou) of China to monitor riverbed deformation during the construction of twin tunnels beneath the Hutuo River in Shijiazhuang, China. A semi-permanent GPS network with one base station outside the river and six rover stations within the river was established for conducting near real-time and long-term monitoring. The distances between the base and the rover antennas are within two kilometers. The network was continuously operating for eight months from April to December 2018. The method is comprised of three components: (1) Monitoring the stability of the base station using precise point positioning (PPP) method, a stable regional reference frame, and a seasonal ground deformation model; (2) monitoring the relative positions of rover stations using the carrier-phase double-difference (DD) positioning method in near real-time; and (3) detecting abrupt and gradual displacements at both base and rover stations using an automated change point detection algorithm. The method is able to detect abrupt positional-changes as minor as five millimeters in near real-time and gradual positional-changes at a couple of millimeters per day within a week. The method has the flexibility of concurrent processing different GPS and BeiDou data sessions (e.g., every 15 minutes, 30 minutes, one hour, one day) for diffident monitoring purposes. This study indicates that BeiDou observations can also achieve few-millimeter-accuracy for measuring displacements. Parallel processing GPS and BeiDou observations can improve the reliability of near real-time structural deformation monitoring and minimize false alerts. The method introduced in this article can be applied to other urban areas for near real-time and long-term structural health monitoring.

scholarly journals Deformation Monitoring and Stability Analysis of Shaft Lining in Weakly Cemented Stratum

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xianzhou Lyu ◽  
Weiming Wang
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Coal Mine ◽  
Deformation Monitoring ◽  
Dynamic Monitoring ◽  
Thick Wall ◽  
Additional Stress ◽  
The Real ◽  
Shaft Lining

Shaft linings in thick weakly cemented stratum have the disadvantages of large deformation and repeated damage after repair. Considering the typical geologic characteristics and the failure characteristics of shaft linings, we establish a multilayer automatic deformation monitoring system in this paper, and the monitoring system can realize the real-time, continuous, and long-term dynamic monitoring on shaft linings. Based on the concrete strength failure criterion under biaxial compression and the analytical solution for spatially axisymmetric problem of thick-wall cylinders, the damage limit of the shaft lining in Xieqiao coal mine is obtained. Then, we choose three sections as the test area according to the typical damage forms of shaft linings to carry out the monitoring scheme on the auxiliary shaft in Xieqiao coal mine. The monitoring results show that the extreme value of the shaft lining deformation is 2.369 mm. And the shaft lining located in the border between the floor aquifer and the bedrock generates the most severe deformation, which is about 89.4% of the deformation limit. The shaft lining deformation increment fluctuates in certain range, which belongs to elastic deformation. Finally, we inverse the stress state according to the deformation value of the shaft lining, and the obtained additional stress is found to be lower than the ultimate compressive strength. Long-term project practice confirms that the deformation monitoring results can reflect the real stress condition of the shaft lining and that the monitoring system can realize the real-time dynamic evaluation for the status of the shaft lining.

Monitoring permafrost changes in the Yangtze River source region of the Qinghai-Tibetan Plateau using differential SAR interferometry

2020 ◽  
Author(s):  
Lingxiao Wang ◽  
Lin Zhao ◽  
Huayun Zhou ◽  
Shibo Liu ◽  
Xiaodong Huang ◽  
...  
Keyword(s):  
Active Layer ◽  
Yangtze River ◽  
Ground Deformation ◽  
Source Region ◽  
Deformation Monitoring ◽  
Tibet Plateau ◽  
Permafrost Degradation ◽  
The Yangtze River ◽  
Ground Ice

<p>Qinghai-Tibet Plateau (QTP) has the largest high-altitude permafrost zone in the middle and low latitudes. Substantial hydrologic changes have been observed in the Yangtze River source region and adjacent areas in the early 21st century. Permafrost on the QTP has undergone degradation under global warming. The ground leveling observation site near Tangula (33°04′N, 91°56′E) located in the degraded alpine meadow indicates that the ground has subsided 50mm since 2011. The contribution of permafrost degradation and loss of ground ice to the hydrologic changes is however still lacking. This study monitors the permafrost changes by applying the Small BAseline Subset InSAR (SBAS-InSAR) technique using C-band Sentinel-1 datasets during 2014-2019. The ground deformation over permafrost terrain is derived in spatial and temporal scale, which reflects the seasonal freeze-thaw cycle in the active layer and long-term thawing of ground ice beneath the active layer. Results show the seasonal thaw displacement exhibits a strong correlation with surficial geology contacts. The ground leveling data is used to validate the ground deformation monitoring results. Then, the ground deformation characteristics are analyzed against the landscape units. Last, the long-term inter-annual displacement value is used to estimate the water equivalent of ground ice melting.</p>

scholarly journals Offline-Online Change Detection for Sentinel-1 InSAR Time Series

2020 ◽  
Author(s):  
Ekbal Hussain ◽  
Alessandro Novellino ◽  
Colm Jordan ◽  
Luke Bateson
Keyword(s):  
Time Series ◽  
Real Time ◽  
Ground Deformation ◽  
Volcanic Eruptions ◽  
Deformation Monitoring ◽  
Real Time Processing ◽  
Spatial Continuity ◽  
Time Deformation ◽  
Population Standard Deviation ◽  
Gradient Change

Traditional applications of Interferometric Synthetic Aperture Radar (InSAR) data involved inverting an interferogram stack to determine the average displacement velocity. While this approach has useful applications in continuously deforming regions, much information is lost by simply fitting a line through the time series. Thanks to regular acquisitions across most of the the world by the ESA Sentinel-1 satellite constellation, we are now in a position to explore opportunities for near-real time deformation monitoring. In this paper we present a simple statistical approach for detecting offsets and gradient changes in InSAR time series. Our key assumption is that 5 years of Sentinel-1 data is sufficient to calculate the population standard deviation of the detection variables. Our offset detector identifies statistically significant peaks in the first, second and third difference series. The gradient change detector identifies statistically significant movements in the second derivative series. We exploit the high spatial resolution of Sentinel-1 data and the spatial continuity of geophysical deformation signals to filter out false positive detections that arise due to signal noise. When combined with near-real time processing of InSAR data these detectors, particularly the gradient change, could be used to detect incipient ground deformation associated with geophysical phenomena, for example from landslides or volcanic eruptions.

scholarly journals Nationwide urban ground deformation monitoring in Japan using Sentinel-1 LiCSAR products and LiCSBAS

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yu Morishita
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Urban Areas ◽  
Ground Deformation ◽  
Processing System ◽  
Economic Loss ◽  
Deformation Monitoring ◽  
Ground Subsidence ◽  
Detection Mechanism ◽  
Series Analysis

AbstractGround subsidence in urban areas is a significant problem because it increases flood risk, damages buildings and infrastructure, and results in economic loss. Continual monitoring of ground deformation is important for early detection, mechanism understanding, countermeasure implementation, and deformation prediction. The Sentinel-1 satellite constellation has globally and freely provided frequent and abundant SAR data and enabled nationwide deformation monitoring through InSAR time series analysis. LiCSAR, an automatic Sentinel-1 interferometric processing system, has produced abundant interferograms with global coverage, and the products are freely accessible and downloadable through a web portal. LiCSBAS, an open source InSAR time series analysis package integrated with LiCSAR, enables users to obtain the deformation time series easily and quickly. In this study, spatially and temporally detailed deformation time series and velocities from the LiCSAR products using LiCSBAS for 73 major urban areas in Japan during 2014–2020 were derived. All LiCSBAS processing was automatically performed using predefined parameters. Many deformation signals with various temporal and spatial features, such as linear subsidence in Hirosaki, Kujyukuri, Niigata, and Kanazawa, episodic subsidence in Sanjo, annual vertical fluctuation in Hirosaki, Yamagata, Yonezawa, Ojiya, and Nogi, and linear uplift in Chofu were detected. Unknown small nonlinear uplift signals were found in Nara and Osaka in 2018. Complex postseismic deformations from the 2016 Kumamoto earthquake were also revealed. All the deformation data obtained in this study are available on an open repository and are expected to be used for further research, investigation, or interpretation. This nationwide monitoring approach using the LiCSAR products and LiCSBAS is easy to implement and applicable to other areas worldwide.

scholarly journals Photogrammetric Deformation Monitoring of the Second Bosphorus Bridge in Istanbul

2014 ◽  
Vol XL-5 ◽  
pp. 71-76 ◽  
Author(s):  
Ö. Avsar ◽  
D. Akca ◽  
O. Altan
Keyword(s):  
Real Time ◽  
Dynamic Load ◽  
Deformation Monitoring ◽  
Bridge Structure ◽  
Bridge Inspection ◽  
The Real ◽  
Structural Deformations ◽  
The Impact

Improving the efficiency of bridge inspection and minimizing the impact of dynamic load on the long term deterioration of the bridge structure reduces maintenance and upkeep costs whilst also improving bridge longevity and safety. This paper presents the results of an on-going project whose ultimate goal is the real-time photogrammetric monitoring the structural deformations of the second Bosphorus Bridge of Istanbul.

scholarly journals Sentinel-1 A-DInSAR Approaches to Map and Monitor Ground Displacements

2021 ◽  
Vol 13 (6) ◽  
pp. 1120
Author(s):  
Vrinda Krishnakumar ◽  
Zhiwei Qiu ◽  
Oriol Monserrat ◽  
Anna Barra ◽  
Juan López-Vinielles ◽  
...  
Keyword(s):  
Urban Areas ◽  
Critical Issue ◽  
Deformation Monitoring ◽  
Deformation Model ◽  
Persistent Scatterer Interferometry ◽  
Point Selection ◽  
Operator Experience ◽  
Persistent Scatterer ◽  
Robust Measurements ◽  
Straightforward Approach

Persistent scatterer interferometry (PSI) is a group of advanced interferometric synthetic aperture radar (SAR) techniques used to measure and monitor terrain deformation. Sentinel-1 has improved the data acquisition throughout and, compared to previous sensors, increased considerably the differential interferometric SAR (DInSAR) and PSI deformation monitoring potential. The low density of persistent scatterer (PS) in non-urban areas is a critical issue in DInSAR and has inspired the development of alternative approaches and refinement of the PS chains. This paper proposes two different and complementary data-driven procedures to obtain terrain deformation maps. These approaches aim to exploit Sentinel-1 highly coherent interferograms and their short revisit time. The first approach, called direct integration (DI), aims at providing a very fast and straightforward approach to screen-wide areas and easily detects active areas. This approach fully exploits the coherent interferograms from consecutive images provided by Sentinel-1, resulting in a very high sampling density. However, it lacks robustness and its usability lays on the operator experience. The second method, called persistent scatterer interferometry geomatics (PSIG) short temporal baseline, provides a constrained application of the PSIG chain, the CTTC approach to the PSI. It uses short temporal baseline interferograms and does not assume any deformation model for point selection. It is also quite a straightforward approach, which improves the performances of the standard PSIG approach, increasing the PS density and providing robust measurements. The effectiveness of the approaches is illustrated through analyses performed on different test sites.

scholarly journals Long-Term Ground Settlements over Mined-Out Region Induced by Railway Construction and Operation

2019 ◽  
Vol 11 (3) ◽  
pp. 875
Author(s):  
Shuo Jiang ◽  
Yimin Wang
Keyword(s):  
Ground Deformation ◽  
Lateral Displacement ◽  
Rapid Development ◽  
Deformation Monitoring ◽  
Ground Subsidence ◽  
Ground Settlement ◽  
Railway Construction ◽  
Train Operation ◽  
Ground Settlements

With the rapid development of railway construction and the massive exploitation of mineral resources, many railway projects have had to cross mining areas and their caverns. However, the settlement of the ground surface may cause severe damage to human-built structures and lead to the loss of human lives. The research on ground deformation monitoring over caverns is undoubtedly important and has a guiding role in railway design. Settlement observation points were set up around the mine, establishing a ground subsidence monitoring level network that has been in operation for 11 years. The ground settlement and lateral displacement along the designed railway were studied. A finite element model was established to predict the long-term ground settlements over the mined-out region induced by designed railway embankment construction and train operation. The results show that the predicted ground settlement induced by railway embankment construction is smaller than the ground settlement induced by the mined-out cavity. One train pass-by has an insignificant impact on the safety of train operation. However, when the number of train pass-bys increases to 10,000,000 times and 20,000,000 times, the cumulative deformations of the ground at different depths are quite large, which may affect the safety of the railway operation. Thus, it is necessary to deal with settlement issues when designing railway construction.

scholarly journals Offline-Online Change Detection for Sentinel-1 InSAR Time Series

2021 ◽  
Vol 13 (9) ◽  
pp. 1656
Author(s):  
Ekbal Hussain ◽  
Alessandro Novellino ◽  
Colm Jordan ◽  
Luke Bateson
Keyword(s):  
Time Series ◽  
Real Time ◽  
Ground Deformation ◽  
Volcanic Eruptions ◽  
Deformation Monitoring ◽  
Real Time Processing ◽  
Spatial Continuity ◽  
Time Deformation ◽  
Population Standard Deviation ◽  
Gradient Change

Traditional applications of Interferometric Synthetic Aperture Radar (InSAR) data involved inverting an interferogram stack to determine the average displacement velocity. While this approach has useful applications in continuously deforming regions, much information is lost by simply fitting a line through the time series. Thanks to regular acquisitions across most of the the world by the ESA Sentinel-1 satellite constellation, we are now in a position to explore opportunities for near-real time deformation monitoring. In this paper we present a statistical approach for detecting offsets and gradient changes in InSAR time series. Our key assumption is that 5 years of Sentinel-1 data is sufficient to calculate the population standard deviation of the detection variables. Our offset detector identifies statistically significant peaks in the first, second and third difference series. The gradient change detector identifies statistically significant movements in the second derivative series. We exploit the high spatial resolution of Sentinel-1 data and the spatial continuity of geophysical deformation signals to filter out false positive detections that arise due to signal noise. When combined with near-real time processing of InSAR data these detectors, particularly the gradient change, could be used to detect incipient ground deformation associated with geophysical phenomena, for example from landslides or volcanic eruptions.

Towards synergy of GNSS and InSAR mining deformation monitoring with Sentinel-1 data

2021 ◽  
Author(s):  
Damian Tondaś ◽  
Maya Ilieva ◽  
Witold Rohm ◽  
Jan Kapłon
Keyword(s):  
Time Series ◽  
Real Time ◽  
Laser Scanning ◽  
Large Scale ◽  
Ground Deformation ◽  
Dimensional Space ◽  
Satellite Navigation ◽  
Deformation Monitoring ◽  
North East ◽  
The Impact

<p>The determination of ground deformation may be carried out by applying various measurement methods such as levelling, laser scanning, satellite navigation systems, Synthetic Aperture Radar (SAR) and many others. In this work, we focus on the comparison of the deformation effects measured by Global Navigation Satellite Systems (GNSS) and satellite Interferometric SAR (InSAR) methods in the Upper-Silesian coal mining region (SW Poland).</p><p>An unquestionable advantage of GNSS technology is the possibility of continuous monitoring of deformations in three-dimensional space. Moreover, the evolution of real-time (RT) techniques such as: near real-time (NRT), ultra-fast NRT or RT allows to obtain a high precise position determination with a relatively slight latency (ranging from a few seconds to less than one hour). The limitation of the satellite navigation technology is the spatial range of the measurements. The deformation can only be observed at the point where the GNSS antenna is located. Furthermore, the acquisition, installation and maintenance of the equipment may also involve high costs.</p><p>In contrast to the GNSS technique, the InSAR methods enable measurement of the large-scale subsidence areas with possibility to use free products and software (e.g. Sentinel-1 and SNAP). The large-scale InSAR investigations provide a better overview of local terrain changes. Unfortunately, InSAR methods also have some limitations related to data acquisition technology:  </p><ul><li>a few days latency in acquiring a new image,</li> <li>insensitivity to changes in the northern component,</li> <li>acquiring deformation only in the LOS direction.</li> </ul><p>The main goal of this research is to analyse the deformation results obtained using GNSS and InSAR methods with respect to the capabilities and limitations of these two techniques. We investigated the level of agreement of eight GNSS and InSAR time series in areas with no subsidence, together with results acquired on seven regions of mining deformation where the maximum subsidence velocity exceeds 50 cm/year. The mean RMS time series fitting error obtained in subsidence basin is more than 5 cm and in non-deformed areas is equal to 2 cm. The study also investigated the effect of coherence threshold levels (0.3 ÷ 0.6) with introduction of the northern GNSS component on the InSAR decomposition process. Assuming the same GNSS deformation value in each directions (north, east, and up), the impact of the northern component was estimated as 10% of the total LOS subsidence.</p>

scholarly journals The Integration of GPS/BDS Real-Time Kinematic Positioning and Visual–Inertial Odometry Based on Smartphones

2021 ◽  
Vol 10 (10) ◽  
pp. 699
Author(s):  
Zun Niu ◽  
Fugui Guo ◽  
Qiangqiang Shuai ◽  
Guangchen Li ◽  
Bocheng Zhu
Keyword(s):  
Real Time ◽  
Urban Areas ◽  
Smartphone Application ◽  
Satellite System ◽  
Kinematic Positioning ◽  
Multiple Sensors ◽  
Real Time Kinematic ◽  
Global Navigation Satellite ◽  
Improved Algorithm

The real-time kinematic positioning technique (RTK) and visual–inertial odometry (VIO) are both promising positioning technologies. However, RTK degrades in GNSS-hostile areas, where global navigation satellite system (GNSS) signals are reflected and blocked, while VIO is affected by long-term drift. The integration of RTK and VIO can improve the accuracy and robustness of positioning. In recent years, smartphones equipped with multiple sensors have become commodities and can provide measurements for integrating RTK and VIO. This paper verifies the feasibility of integrating RTK and VIO using smartphones, and we propose an improved algorithm to integrate RTK and VIO with better performance. We began by developing an Android smartphone application for data collection and then wrote a Python program to convert the data to a robot operating system (ROS) bag. Next, we established two ROS nodes to calculate the RTK results and accomplish the integration. Finally, we conducted experiments in urban areas to assess the integration of RTK and VIO based on smartphones. The results demonstrate that the integration improves the accuracy and robustness of positioning and that our improved algorithm reduces altitude deviation. Our work can aid navigation and positioning research, which is the reason why we open source the majority of the codes at our GitHub.

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