Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13417
C. Eschelbach, M. Lösler
The Global Geodetic Observing System (GGOS) aims for an accuracy of 1 mm in position concerning a global geodetic reference frame such as the International Terrestrial Reference Frame (ITRF). To derive a global frame, several space geodetic techniques are combined. The combination procedure requires the geometric relations between the invariant reference points of these techniques, the so-called local tie vectors. Each space geodetic technique defines its reference point individually, so the determination of the position of the reference point varies significantly between techniques. Within the international GeoMetre project, measurement systems and analysis strategies are developed to improve the quality of local tie vectors and, thus, the quality of the resulting global frame. The use of close range photogrammetry to determine the reference point of a telescope used for Satellite Laser Ranging (SLR) at the GGOS core station Wettzell in September 2020 is considered as a milestone in this project. This contribution deals with a novel approach for an accelerated reference point determination using close range photogrammetry. In comparison to the conventional photogrammetric approach, published so far, this new approach leads to a significant reduction in recording time. However, in case of inappropriate measurement configuration the approach also bears the risk of biased results. Most importantly, the new approach has the potential to be automated, which is one of the primary calls of GGOS for reference point determinations.
{"title":"A feasibility study for accelerated reference point determination using close range photogrammetry","authors":"C. Eschelbach, M. Lösler","doi":"10.4995/jisdm2022.2022.13417","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13417","url":null,"abstract":"The Global Geodetic Observing System (GGOS) aims for an accuracy of 1 mm in position concerning a global geodetic reference frame such as the International Terrestrial Reference Frame (ITRF). To derive a global frame, several space geodetic techniques are combined. The combination procedure requires the geometric relations between the invariant reference points of these techniques, the so-called local tie vectors. Each space geodetic technique defines its reference point individually, so the determination of the position of the reference point varies significantly between techniques. Within the international GeoMetre project, measurement systems and analysis strategies are developed to improve the quality of local tie vectors and, thus, the quality of the resulting global frame. The use of close range photogrammetry to determine the reference point of a telescope used for Satellite Laser Ranging (SLR) at the GGOS core station Wettzell in September 2020 is considered as a milestone in this project. This contribution deals with a novel approach for an accelerated reference point determination using close range photogrammetry. In comparison to the conventional photogrammetric approach, published so far, this new approach leads to a significant reduction in recording time. However, in case of inappropriate measurement configuration the approach also bears the risk of biased results. Most importantly, the new approach has the potential to be automated, which is one of the primary calls of GGOS for reference point determinations.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133307114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13826
G. Bru, Juan J. Portela, P. Ezquerro, M. Navarro, A. Staller, M. Béjar-Pizarro, C. Guardiola‐Albert, J. Fernández-Merodo, J. López-Vinielles, R. Tomás, J. Lopez-Sanchez
Aquifer overexploitation can lead to the irreversible loss of groundwater storage caused by the compaction or consolidation of unconsolidated fine-grained sediments resulting in land subsidence. Advanced Differential SAR Interferometry (A-DINSAR) is particularly efficient to monitor progressive ground movements, making it an appropriate method to study depleting aquifers undergoing overexploitation and land subsidence. The Guadalentín River Basin (Murcia, Spain) is a widely recognized subsiding area that exhibits the highest rates of groundwater-related land subsidence recorded in Europe (>10 cm/yr). The basin covers an extension of more than 500 km2 and is underlain by an overexploited aquifer-system formed by two contiguous hydraulically connected units (Alto Guadalentín and Bajo Guadalentín). Although during the last years the piezometric levels have partially stabilized, the ongoing aquifer-system deformation is evident and significant, as revealed by the A-DInSAR analysis presented. In this work, we submit the first vertical and horizontal (E-W) decomposition results of the LOS velocity and displacement time series of the whole Guadalentín Basin obtained from two datasets of Sentinel-1 SAR acquisitions in ascending and descending modes. The images cover the period from 2015 to 2021 and they were processed using the Parallel Small BAseline Subset (P-SBAS) implemented by CNR-IREA in the Geohazards Exploitation Platform (GEP) on-demand web tool, which is funded by the European Space Agency. The output ascending and descending measurement points of P-SBAS lie on the same regular grid, which is particularly suited for the geometrical decomposition. Time series displacements are compared to a permanent GNSS station located in the Bajo Guadalentín basin.
{"title":"Imaging land subsidence in the Guadalentín River Basin (SE Spain) using Advanced Differential SAR Interferometry","authors":"G. Bru, Juan J. Portela, P. Ezquerro, M. Navarro, A. Staller, M. Béjar-Pizarro, C. Guardiola‐Albert, J. Fernández-Merodo, J. López-Vinielles, R. Tomás, J. Lopez-Sanchez","doi":"10.4995/jisdm2022.2022.13826","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13826","url":null,"abstract":"Aquifer overexploitation can lead to the irreversible loss of groundwater storage caused by the compaction or consolidation of unconsolidated fine-grained sediments resulting in land subsidence. Advanced Differential SAR Interferometry (A-DINSAR) is particularly efficient to monitor progressive ground movements, making it an appropriate method to study depleting aquifers undergoing overexploitation and land subsidence. The Guadalentín River Basin (Murcia, Spain) is a widely recognized subsiding area that exhibits the highest rates of groundwater-related land subsidence recorded in Europe (>10 cm/yr). The basin covers an extension of more than 500 km2 and is underlain by an overexploited aquifer-system formed by two contiguous hydraulically connected units (Alto Guadalentín and Bajo Guadalentín). Although during the last years the piezometric levels have partially stabilized, the ongoing aquifer-system deformation is evident and significant, as revealed by the A-DInSAR analysis presented. In this work, we submit the first vertical and horizontal (E-W) decomposition results of the LOS velocity and displacement time series of the whole Guadalentín Basin obtained from two datasets of Sentinel-1 SAR acquisitions in ascending and descending modes. The images cover the period from 2015 to 2021 and they were processed using the Parallel Small BAseline Subset (P-SBAS) implemented by CNR-IREA in the Geohazards Exploitation Platform (GEP) on-demand web tool, which is funded by the European Space Agency. The output ascending and descending measurement points of P-SBAS lie on the same regular grid, which is particularly suited for the geometrical decomposition. Time series displacements are compared to a permanent GNSS station located in the Bajo Guadalentín basin.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131586340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13902
Agnes Weinhuber, A. Neidhardt, C. Holst
Quasars are nowadays the basis to determine the world’s absolute orientation in space by radio interferometry (VLBI). The global network of baselines measured by the used radio telescopes, which vary greatly in size, is subject to various influences that have an impact on the International Terrestrial Reference Frame. Among others, those influences are imperfections of individual panels of the dishes, a possible elevation dependent deformation of the whole dish and a shift of the reference point due to gravitational influences. In this study, we monitor the elevation dependent deformation of the main reflector of the 20 m radio telescope of the Geodetic Observatory Wettzell by a Leica RTC360 laser scanner. For this task, we mount the terrestrial laser scanner overhead near the subreflector to capture the surface of the moving dish at each elevation angle. This study focusses on 1) introducing further redundancy in the measurement and processing strategy to gain a reliable and accurate result even the used scanner is a no high-end one. This furthermore leads to 2) investigations whether there are differences in the results between in related work used high-end scanners and the RTC360 and thus 3) whether the RTC360 proves to be capable to detect deformations at a radio telescope’s main reflector. Using these three foci, we show that deformations in the main reflector between elevations can be reliably determined areal and in focal length by redundant measurements with the RTC360. It is also shown that the results are less sensitive to axis errors compared to those obtained with high-end scanners. However, the compensations also show that the application scanner has certain systematics, which must be investigated in further steps.
{"title":"Monitoring Gravitational Deformations of the Wettzell 20 m Radio Telescope’s Main Reflector Using a Leica RTC360","authors":"Agnes Weinhuber, A. Neidhardt, C. Holst","doi":"10.4995/jisdm2022.2022.13902","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13902","url":null,"abstract":"Quasars are nowadays the basis to determine the world’s absolute orientation in space by radio interferometry (VLBI). The global network of baselines measured by the used radio telescopes, which vary greatly in size, is subject to various influences that have an impact on the International Terrestrial Reference Frame. Among others, those influences are imperfections of individual panels of the dishes, a possible elevation dependent deformation of the whole dish and a shift of the reference point due to gravitational influences. In this study, we monitor the elevation dependent deformation of the main reflector of the 20 m radio telescope of the Geodetic Observatory Wettzell by a Leica RTC360 laser scanner. For this task, we mount the terrestrial laser scanner overhead near the subreflector to capture the surface of the moving dish at each elevation angle. This study focusses on 1) introducing further redundancy in the measurement and processing strategy to gain a reliable and accurate result even the used scanner is a no high-end one. This furthermore leads to 2) investigations whether there are differences in the results between in related work used high-end scanners and the RTC360 and thus 3) whether the RTC360 proves to be capable to detect deformations at a radio telescope’s main reflector. Using these three foci, we show that deformations in the main reflector between elevations can be reliably determined areal and in focal length by redundant measurements with the RTC360. It is also shown that the results are less sensitive to axis errors compared to those obtained with high-end scanners. However, the compensations also show that the application scanner has certain systematics, which must be investigated in further steps.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121604030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13891
P. Rossi, C. Castagnetti, S. Cattini, G. Di Loro, F. Grassi, L. Parente, Sara Righi, L. Rovati, R. Simonini, A. Capra
The development and testing of innovative technologies and automated data analysis methodologies offer tools for investigations in numerous scenarios including the monitoring of complex marine ecosystems and the direct and indirect effects of climate change on natural heritage. In the underwater environment, the creation of products with accurate metric and colorimetric content is a scientific and technological challenge, that can offer tools for new investigations including the monitoring of ecosystems and the study of biodiversity. The research group developed a technological solution consisting of a remotely operating platform and a measuring system that includes RGB and fluorescence optical sensors for the 3D reconstruction of the underwater environment and the study of the health-state of investigated species. The proposed solution aspires to high-accuracy multiscale reconstruction of underwater animal forests with a special focus on metric content. Methodologies and technical solutions for the management and calibration of the system have been developed: the design of proper calibration frames and the fluorescence sensor, the choice of a proper illumination system, the implementation of the system on a customizable Remotely Operating Vehicle, the integration of the different sensors, the combination of metric and colorimetric results for monitoring the occurred deformations and the health status. The results of laboratory activities and preliminary tests on field tests are discussed.
{"title":"Monitoring of underwater animal forests: geometry and biometry","authors":"P. Rossi, C. Castagnetti, S. Cattini, G. Di Loro, F. Grassi, L. Parente, Sara Righi, L. Rovati, R. Simonini, A. Capra","doi":"10.4995/jisdm2022.2022.13891","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13891","url":null,"abstract":"The development and testing of innovative technologies and automated data analysis methodologies offer tools for investigations in numerous scenarios including the monitoring of complex marine ecosystems and the direct and indirect effects of climate change on natural heritage. In the underwater environment, the creation of products with accurate metric and colorimetric content is a scientific and technological challenge, that can offer tools for new investigations including the monitoring of ecosystems and the study of biodiversity. The research group developed a technological solution consisting of a remotely operating platform and a measuring system that includes RGB and fluorescence optical sensors for the 3D reconstruction of the underwater environment and the study of the health-state of investigated species. The proposed solution aspires to high-accuracy multiscale reconstruction of underwater animal forests with a special focus on metric content. Methodologies and technical solutions for the management and calibration of the system have been developed: the design of proper calibration frames and the fluorescence sensor, the choice of a proper illumination system, the implementation of the system on a customizable Remotely Operating Vehicle, the integration of the different sensors, the combination of metric and colorimetric results for monitoring the occurred deformations and the health status. The results of laboratory activities and preliminary tests on field tests are discussed.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130521632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13839
D. Roque, Martino Correia, R. Cabral, S. Davies, Tiago Cordeiro, A. Fonseca, Paulo Barreto
In this study, the failure of a slope adjacent to a motorway was back-analyzed based on InSAR data. The location of the slided area and the exact date of the event were not known in advance. A post-processing strategy was applied on the displacement time series in order to aid the detection of instability signs and to enable the identification of the location and the narrowing down of the time interval of the slide. InSAR displacement time series were obtained following the small baseline subset approach implemented on an automatic processing platform. Distributed scatterers were clustered based on the similarity of their displacement time series, in order to form clusters of scatterers with similar behavior. This procedure allowed the computation of displacement time series representative of each cluster, aiding the detection of instability signs on the slope. One of the clusters showed a sudden movement away from the SAR sensor. It was later confirmed that the slide had occurred at the location of the scatterers belonging to that cluster and during the time interval between the two observation epochs corresponding to the break in the time series. In conclusion, the proposed method was effective in the back-analysis of the slope failure, hopefully contributing to the uptake of InSAR technology by structural safety experts.
{"title":"InSAR displacement time series post-processing to back-analyze a slope failure","authors":"D. Roque, Martino Correia, R. Cabral, S. Davies, Tiago Cordeiro, A. Fonseca, Paulo Barreto","doi":"10.4995/jisdm2022.2022.13839","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13839","url":null,"abstract":"In this study, the failure of a slope adjacent to a motorway was back-analyzed based on InSAR data. The location of the slided area and the exact date of the event were not known in advance. A post-processing strategy was applied on the displacement time series in order to aid the detection of instability signs and to enable the identification of the location and the narrowing down of the time interval of the slide. InSAR displacement time series were obtained following the small baseline subset approach implemented on an automatic processing platform. Distributed scatterers were clustered based on the similarity of their displacement time series, in order to form clusters of scatterers with similar behavior. This procedure allowed the computation of displacement time series representative of each cluster, aiding the detection of instability signs on the slope. One of the clusters showed a sudden movement away from the SAR sensor. It was later confirmed that the slide had occurred at the location of the scatterers belonging to that cluster and during the time interval between the two observation epochs corresponding to the break in the time series. In conclusion, the proposed method was effective in the back-analysis of the slope failure, hopefully contributing to the uptake of InSAR technology by structural safety experts.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127734819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13620
Andreas Baumann-Ouyang, J. Butt, A. Wieser
Sensors capable of measuring surface deformations with areal coverage and high spatial and temporal resolution are beneficial for many monitoring applications. However, such sensors are typically expensive, or their configuration cannot be adapted flexibly by the user like in case of satellite-based systems. Automotive Multiple-Input-Multiple-Output Synthetic Aperture Radar (MIMO-SAR) systems are interesting potential alternatives associated with low cost and high flexibility. In this paper, we present an experimental investigation showing the capabilities of a particular off-the-shelf, automotive radar system for structural monitoring. We analyse the accuracy of the measured line-of-sight displacements, the spatial and temporal resolution, and the impact of simultaneous coverage of the same area by two sensors of the same type. Finally, we demonstrate the MIMO-SAR system in a real-world use case measuring deformations of a railway bridge in response to dynamic load by trains passing over it. We operated two MIMO-SAR sensors simultaneously, analyse and interpret the individual interferograms and combine the data to derive the temporal and spatial distribution of vertical displacements along selected profiles. The results show that off-the-shelf automotive-grade MIMO-SAR systems can be used to quantify sub-millimetre deformations of structures and derive high-resolution time series beneficial for structural health monitoring applications.
{"title":"Bridge deformations during train passage: monitoring multiple profiles using concurrently operating MIMO-SAR sensors","authors":"Andreas Baumann-Ouyang, J. Butt, A. Wieser","doi":"10.4995/jisdm2022.2022.13620","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13620","url":null,"abstract":"Sensors capable of measuring surface deformations with areal coverage and high spatial and temporal resolution are beneficial for many monitoring applications. However, such sensors are typically expensive, or their configuration cannot be adapted flexibly by the user like in case of satellite-based systems. Automotive Multiple-Input-Multiple-Output Synthetic Aperture Radar (MIMO-SAR) systems are interesting potential alternatives associated with low cost and high flexibility. In this paper, we present an experimental investigation showing the capabilities of a particular off-the-shelf, automotive radar system for structural monitoring. We analyse the accuracy of the measured line-of-sight displacements, the spatial and temporal resolution, and the impact of simultaneous coverage of the same area by two sensors of the same type. Finally, we demonstrate the MIMO-SAR system in a real-world use case measuring deformations of a railway bridge in response to dynamic load by trains passing over it. We operated two MIMO-SAR sensors simultaneously, analyse and interpret the individual interferograms and combine the data to derive the temporal and spatial distribution of vertical displacements along selected profiles. The results show that off-the-shelf automotive-grade MIMO-SAR systems can be used to quantify sub-millimetre deformations of structures and derive high-resolution time series beneficial for structural health monitoring applications.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129530056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13865
O. Monserrat, A. Barra, C. Reyes-Carmona, M. Cuevas, M. Béjar-Pizarro, J. Navarro, R. Tomás, J. Galve, L. Solari, R. Sarro, R. M. Mateos, J. Azañón, G. Herrera, B. Crippa
The SAR Interferometry techniques, Persistent Scatterer Interferometry (PSI) among them, are nowadays known as important tools for monitoring Earth surface movements. Several regional and national Ground Motion Services based on PSI already exist. Moreover, since 2022 the European Ground Motion Service will be operational and will annually provide an updated displacement map over the whole Europe. This will suppose a big amount of ground displacement measurements along the European territory. For each measurement EGMS will provide the annual velocity and the time series of deformation covering the period 2014 to one year prior to each delivery. In this context, it will be more and more necessary having tools to ease the management, analysis, and interpretation, of those wide areas and huge amount of data. We present here a first step in this direction: the ADATools are a set of tools to automatically have secondary, and more operational, products derived from a PSI map. Starting from a fast extraction of the most significant Active Deformation Areas (ADA), with the ADAFinder tool, then we can have a preliminary classification of the most probable phenomena (landslides, subsidence, settlements, or sinkholes) that is behind the detected movement, with the ADAClassifier tool. Moreover, LOS2hv tool allows to derive the horizontal (east-west) and vertical components of the movement in case we have maps of ascending and descending geometries. Finally, it is presented a product that analyzes the local displacement gradients to generate potential damage maps in urban areas. The tools will be presented thorough some results obtained on an area of the Granada County with the use of Sentinel-1 data. All the results have been achieved within the framework of the Riskcoast Project (financed by the Interreg Sudoe Program through the European Regional Development Fund, ERDF).
{"title":"ADATools: a set of tools for the analysis of terrain movement maps obtained with SAR Interferometry","authors":"O. Monserrat, A. Barra, C. Reyes-Carmona, M. Cuevas, M. Béjar-Pizarro, J. Navarro, R. Tomás, J. Galve, L. Solari, R. Sarro, R. M. Mateos, J. Azañón, G. Herrera, B. Crippa","doi":"10.4995/jisdm2022.2022.13865","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13865","url":null,"abstract":"The SAR Interferometry techniques, Persistent Scatterer Interferometry (PSI) among them, are nowadays known as important tools for monitoring Earth surface movements. Several regional and national Ground Motion Services based on PSI already exist. Moreover, since 2022 the European Ground Motion Service will be operational and will annually provide an updated displacement map over the whole Europe. This will suppose a big amount of ground displacement measurements along the European territory. For each measurement EGMS will provide the annual velocity and the time series of deformation covering the period 2014 to one year prior to each delivery. In this context, it will be more and more necessary having tools to ease the management, analysis, and interpretation, of those wide areas and huge amount of data. We present here a first step in this direction: the ADATools are a set of tools to automatically have secondary, and more operational, products derived from a PSI map. Starting from a fast extraction of the most significant Active Deformation Areas (ADA), with the ADAFinder tool, then we can have a preliminary classification of the most probable phenomena (landslides, subsidence, settlements, or sinkholes) that is behind the detected movement, with the ADAClassifier tool. Moreover, LOS2hv tool allows to derive the horizontal (east-west) and vertical components of the movement in case we have maps of ascending and descending geometries. Finally, it is presented a product that analyzes the local displacement gradients to generate potential damage maps in urban areas. The tools will be presented thorough some results obtained on an area of the Granada County with the use of Sentinel-1 data. All the results have been achieved within the framework of the Riskcoast Project (financed by the Interreg Sudoe Program through the European Regional Development Fund, ERDF).","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128511052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13729
M. Kuschnerus, R. Lindenbergh, S. de Vries
Coastal zones are highly dynamic, and their topography is subject to constant deformation. These deformations are governed by sediment transports that are forced by environmental conditions of waves, tides and wind which result in topographic changes at various spatial and temporal scales. In the view of climate change and intensification of extreme weather events, it is important for coastal management to monitor the deformation and coastal topography with high accuracy. To demonstrate a novel way of deriving these deformations and of analyzing the underlying processes, we use permanent laser scanning (PLS) to monitor part of the typical urban coastal beach in Noordwijk, The Netherlands. A laser scanner permanently installed on a hotel building acquired one 3D point cloud of the sandy beach and dunes every hour, continuously, for a duration of two years. The resulting spatio-temporal data set consists of ~ 15 000 point clouds and contains the evolution of a section of the coast of ~ 1 km length at great detail. The elevation changes are observed at centimeter level, allowing to monitor even small scale and slow processes. However, this information is not readily available from the extensive data set. By deriving digital elevation models (DEMs) from each point cloud and collecting elevation data as time series per spatial grid cell, we structure the data in an efficient way. We use the DEMs to estimate two parameters describing the coastal deformation, beach width and intertidal width. We also extract the shoreline at low and high tide for a part of the data set and estimate beach width and intertidal width from them. We find that heavy storms influence the location of the shoreline and the intertidal width in particular. Ultimately, the estimated beach width and intertidal width at high temporal frequency (monthly) and with high spatial accuracy (meters) helps coastal management to improve the understanding of coastal deformation processes.
{"title":"Assessing sandy beach width variations on intertidal time scales using permanent laser scanning","authors":"M. Kuschnerus, R. Lindenbergh, S. de Vries","doi":"10.4995/jisdm2022.2022.13729","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13729","url":null,"abstract":"Coastal zones are highly dynamic, and their topography is subject to constant deformation. These deformations are governed by sediment transports that are forced by environmental conditions of waves, tides and wind which result in topographic changes at various spatial and temporal scales. In the view of climate change and intensification of extreme weather events, it is important for coastal management to monitor the deformation and coastal topography with high accuracy. To demonstrate a novel way of deriving these deformations and of analyzing the underlying processes, we use permanent laser scanning (PLS) to monitor part of the typical urban coastal beach in Noordwijk, The Netherlands. A laser scanner permanently installed on a hotel building acquired one 3D point cloud of the sandy beach and dunes every hour, continuously, for a duration of two years. The resulting spatio-temporal data set consists of ~ 15 000 point clouds and contains the evolution of a section of the coast of ~ 1 km length at great detail. The elevation changes are observed at centimeter level, allowing to monitor even small scale and slow processes. However, this information is not readily available from the extensive data set. By deriving digital elevation models (DEMs) from each point cloud and collecting elevation data as time series per spatial grid cell, we structure the data in an efficient way. We use the DEMs to estimate two parameters describing the coastal deformation, beach width and intertidal width. We also extract the shoreline at low and high tide for a part of the data set and estimate beach width and intertidal width from them. We find that heavy storms influence the location of the shoreline and the intertidal width in particular. Ultimately, the estimated beach width and intertidal width at high temporal frequency (monthly) and with high spatial accuracy (meters) helps coastal management to improve the understanding of coastal deformation processes.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130124240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13678
R. Duchnowski, P. Wyszkowska
Various measurement techniques and data processing are applied to determine point displacements and deformation of geodetic networks or buildings. Considering classical measurements and analysis of the network deformation, we should realize that the measurements are not “immediate.” The question arises: what happens if a point (or some points) displaces between particular measurements within one epoch. In such a case, the observation set would consist of the observations before and after point displacement, and such hypothetical observation groups can be regarded as related to two (or more) pseudo epochs. The paper's main objective is to examine some estimation methods that would probably deal with such a problem, namely Msplit estimation (in two variants, the squared and the absolute Msplit estimation) and chosen robust methods, namely Huber’s method (example M-estimation) and the Hodges-Lehmann weighted estimation (basic R-estimation). The first approach can provide two (or more) variants of the network point coordinates (here, before and after point movements), providing information about two (or more) states of the network during measurements. In contrast, the robust methods can only decrease the influence of the outliers on the computed network point coordinates. Thus, estimation results would concern only one network state in such a case. The presented empirical analyses show that the better and more realistic results are obtained by applying Msplit estimation. Huber’s method can also provide acceptable results (describing the network state at the epoch beginning) only if the number of observations conducted after the point displacements is not too high.
{"title":"Point displacements during classical measurements – a practical approach to pseudo epochs between measurements","authors":"R. Duchnowski, P. Wyszkowska","doi":"10.4995/jisdm2022.2022.13678","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13678","url":null,"abstract":"Various measurement techniques and data processing are applied to determine point displacements and deformation of geodetic networks or buildings. Considering classical measurements and analysis of the network deformation, we should realize that the measurements are not “immediate.” The question arises: what happens if a point (or some points) displaces between particular measurements within one epoch. In such a case, the observation set would consist of the observations before and after point displacement, and such hypothetical observation groups can be regarded as related to two (or more) pseudo epochs. The paper's main objective is to examine some estimation methods that would probably deal with such a problem, namely Msplit estimation (in two variants, the squared and the absolute Msplit estimation) and chosen robust methods, namely Huber’s method (example M-estimation) and the Hodges-Lehmann weighted estimation (basic R-estimation). The first approach can provide two (or more) variants of the network point coordinates (here, before and after point movements), providing information about two (or more) states of the network during measurements. In contrast, the robust methods can only decrease the influence of the outliers on the computed network point coordinates. Thus, estimation results would concern only one network state in such a case. The presented empirical analyses show that the better and more realistic results are obtained by applying Msplit estimation. Huber’s method can also provide acceptable results (describing the network state at the epoch beginning) only if the number of observations conducted after the point displacements is not too high.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128989917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13907
Mert Bezcioglu, Barış Karadeniz, C. O. Yigit, A. Dindar, B. Akpınar
Thanks to advances in receiver and software technology, the high-rate GPS (Global Positioning System) technique has become very important in monitoring the dynamic behavior of man-made structures in both real-time and post-missions. Real-time monitoring of the changes in the behavior of structures due to effects such as natural disasters, wind effect, traffic loading is critical in order to take precautions in time. In this study, the performance of the Real-Time Single Frequency Precision Point Positioning (RT SF-PPP) method based on IGS (International GNSS Service) RTS (real-time stream) products to capture the behavior of dynamic motions was evaluated. The performance of the SF RT-PPP method to detect dynamic behaviors was evaluated based on 20 Hz single frequency GPS observations obtained from shake table experiments, including 10 mm amplitude and different oscillation frequencies including 0.1, 0.6, 1.0, 2.0 and 3.0 Hz. RT SF-PPP results were compared with reference LVDT (Linear Variable Differential Transformer) and relative (or double difference) GPS positioning both frequency and time domain. Results show that the high-rate RT SF-PPP method can capture the frequencies and amplitudes of harmonic motions and it is comparable to LVDT and Relative GPS positioning solutions. These results show that the high-rate RT SF-PPP method can monitor earthquake-induced real-time vibration frequencies and amplitudes, which is especially important for early warning systems.
{"title":"High-rate real-time single-frequency PPP for structural motion detection in horizontal directions","authors":"Mert Bezcioglu, Barış Karadeniz, C. O. Yigit, A. Dindar, B. Akpınar","doi":"10.4995/jisdm2022.2022.13907","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13907","url":null,"abstract":"Thanks to advances in receiver and software technology, the high-rate GPS (Global Positioning System) technique has become very important in monitoring the dynamic behavior of man-made structures in both real-time and post-missions. Real-time monitoring of the changes in the behavior of structures due to effects such as natural disasters, wind effect, traffic loading is critical in order to take precautions in time. In this study, the performance of the Real-Time Single Frequency Precision Point Positioning (RT SF-PPP) method based on IGS (International GNSS Service) RTS (real-time stream) products to capture the behavior of dynamic motions was evaluated. The performance of the SF RT-PPP method to detect dynamic behaviors was evaluated based on 20 Hz single frequency GPS observations obtained from shake table experiments, including 10 mm amplitude and different oscillation frequencies including 0.1, 0.6, 1.0, 2.0 and 3.0 Hz. RT SF-PPP results were compared with reference LVDT (Linear Variable Differential Transformer) and relative (or double difference) GPS positioning both frequency and time domain. Results show that the high-rate RT SF-PPP method can capture the frequencies and amplitudes of harmonic motions and it is comparable to LVDT and Relative GPS positioning solutions. These results show that the high-rate RT SF-PPP method can monitor earthquake-induced real-time vibration frequencies and amplitudes, which is especially important for early warning systems.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121839194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：