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Wickramanayake, Anura
Publikasjoner (4 av 4) Visa alla publikasjoner
Wickramanayake, A., Hanshel, M., Hobbs, S., Buehler, S., Ekman, J. & Lehrbass, B. (2016). Seasonal Variation of Coherence in SAR Interferograms in Kiruna, Northern Sweden (ed.). Paper presented at . International Journal of Remote Sensing, 37(2), 370-387
Åpne denne publikasjonen i ny fane eller vindu >>Seasonal Variation of Coherence in SAR Interferograms in Kiruna, Northern Sweden
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2016 (engelsk)Inngår i: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 37, nr 2, s. 370-387Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

This article presents the results of a study conducted to quantify the seasonal variation of coherence in synthetic aperture radar (SAR) interferograms in Kiruna, Northern Sweden. In SAR interferometry (InSAR), coherence is an important concept that provides a good indication of the phase stability of the scatterers. Therefore, in this study, the degree of coherence is used as a parameter to identify the seasonal variation interferograms. For this study, 34 Radarsat-2 ultra-fine beam mode (U6D) images of the Kiruna area (67°51ʹN, 20°14ʹE) and the improved digital elevation model (DEM) created by merging the Radarsat-2 DEM and ASTER DEM were used to produce 561 differential interferograms. The interferograms were arranged in three different ways for the analysis, with the first including common master interferograms (with the summer master image), the second including the sequential interferograms that have the shortest temporal baseline, and the third accounting for all possible combinations of the interferograms (full network of interferograms). Following this step, the variation of coherence for forest areas, urban areas, and flat waste rock areas was studied. This study shows that interferograms generated for the Kiruna region exhibit seasonal variations in coherence due to the ground snow layer in winter. Furthermore, when there is water on the ground due to the melting of the snow layer (in the spring) or due to rains in autumn, the coherence is reduced considerably. Another significant feature is that there is a significant change in summer-to-summer coherence for some regions even over the course of a few years. Based on this study, it is clear that the winter Radarsat-2 U6D beam mode images are not suitable for differential interferometric SAR (DInSAR) deformation measurements in flat waste rock regions in Kiruna. It is expected that even with winter images, PSInSAR or CTM techniques will be able to provide better deformation measurements, but, in this study, those techniques were not assessed. The next step will be to study the seasonal variations in coherence in natural or man-made targets/persistent scatterers using persistent scatter InSAR (PSInSAR) or coherence target monitoring (CTM) techniques

HSV kategori
Forskningsprogram
Industriell elektronik; Rymdteknik
Identifikatorer
urn:nbn:se:ltu:diva-12592 (URN)10.1080/01431161.2014.915435 (DOI)000368724700007 ()2-s2.0-84954555393 (Scopus ID)bc17dd6e-cd79-4897-b239-bc5c3e1303f8 (Lokal ID)bc17dd6e-cd79-4897-b239-bc5c3e1303f8 (Arkivnummer)bc17dd6e-cd79-4897-b239-bc5c3e1303f8 (OAI)
Prosjekter
Improved measurements of mining induced ground deformations using GPS and SAR techniques
Merknad
Validerad; 2016; Nivå 2; 20120201 (jekman)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Wickramanayake, A., Ekman, J., Buehler, S. & Hobbs, S. (2012). Mine induced deformation measurements using SAR interferometry at high latitudes (ed.). Paper presented at IEEE International Geoscience and Remote Sensing Symposium : 22/07/2012 - 27/07/2012. Paper presented at IEEE International Geoscience and Remote Sensing Symposium : 22/07/2012 - 27/07/2012.
Åpne denne publikasjonen i ny fane eller vindu >>Mine induced deformation measurements using SAR interferometry at high latitudes
2012 (engelsk)Konferansepaper, Oral presentation only (Fagfellevurdert)
HSV kategori
Forskningsprogram
Industriell elektronik; Rymdteknik
Identifikatorer
urn:nbn:se:ltu:diva-38301 (URN)ca576126-e47b-4f81-a782-43fff3b466b5 (Lokal ID)ca576126-e47b-4f81-a782-43fff3b466b5 (Arkivnummer)ca576126-e47b-4f81-a782-43fff3b466b5 (OAI)
Konferanse
IEEE International Geoscience and Remote Sensing Symposium : 22/07/2012 - 27/07/2012
Prosjekter
Improved measurements of mining induced ground deformations using GPS and SAR techniques
Merknad
Godkänd; 2012; 20121008 (anuwic)Tilgjengelig fra: 2016-10-03 Laget: 2016-10-03 Sist oppdatert: 2017-11-25bibliografisk kontrollert
Ekman, J., Lindgren, T. & Wickramanayake, A. (2011). Project: Improved measurements of mining induced ground deformations using GPS and SAR techniques. Paper presented at .
Åpne denne publikasjonen i ny fane eller vindu >>Project: Improved measurements of mining induced ground deformations using GPS and SAR techniques
2011 (engelsk)Annet (Annet (populærvitenskap, debatt, mm))
Abstract [en]

The LKAB SAR project is implemented to measure the subsidence and terrain deformation around the Kiruna iron ore mine and in the Kiruna city area. The LKAB SAR project has two components. One is the monitoring component in which MDA (main contractor) provides the SAR deformation maps to LKAB and the second is the technology transfer component in where MDA provides theoretical and practical knowledge to LKAB so that LKAB can produce deformation maps by their own. And Cranfield University and Luleå University of technology will carryout the LKAB SAR research. During the SAR project it is expected to use “DInSAR” and “CTM” techniques to measure the deformations. By using DInSAR and CTM techniques, LKAB can achieve the required accuracy levels during the summer season but it is likely that the quality and quantity of the measurements will largely differ during winter season (due to the thick snow cover). Similarly, areas which have thick forest cover will prevent radar waves reaching the ground and because of that it is likely the quality and quantity of the measurements will decrease in such areas during the mid summer period. Therefore LKAB is planning to carry out a research program to improve the SAR measurements.

HSV kategori
Forskningsprogram
Industriell elektronik
Identifikatorer
urn:nbn:se:ltu:diva-36180 (URN)9c48f137-9df6-438e-98a5-8ea304cdd290 (Lokal ID)9c48f137-9df6-438e-98a5-8ea304cdd290 (Arkivnummer)9c48f137-9df6-438e-98a5-8ea304cdd290 (OAI)
Merknad

Publikationer: Seasonal Variation of Coherence in SAR Interferograms in Kiruna, Northern Sweden; Mine induced deformation measurements using SAR interferometry at high latitudes; Status: Ongoing; Period: 15/08/2009 → 15/08/2013; End date: 15/08/2013

Tilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2017-11-25bibliografisk kontrollert
Hobbs, S., Wickramanayake, A., Sjöberg, J., Lindgren, T., Henschel, M. & Fernando, P. (2011). SAR inteferometry with seasonally changing snow cover (ed.). Paper presented at International Workshop on "Advances in the Science and Applications of SAR Interferometry" : FRINGE 2011 Workshop 19/09/2011 - 23/09/2011. Paper presented at International Workshop on "Advances in the Science and Applications of SAR Interferometry" : FRINGE 2011 Workshop 19/09/2011 - 23/09/2011.
Åpne denne publikasjonen i ny fane eller vindu >>SAR inteferometry with seasonally changing snow cover
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2011 (engelsk)Konferansepaper, Oral presentation only (Fagfellevurdert)
Abstract [en]

Spaceborne radar interferometry is an established and very powerful method of measuring land subsidence over timescales of weeks to years. It has been demonstrated on natural and urban landscapes and is becoming an operational technique with accuracy better than 1 cm yr-1. The technique generally relies on having scatterers (which reflect the radar signal) which have stable properties over the timescale of interest. In some landscapes these scatterers occur naturally. However, at high latitudes there are particular difficulties because of the strong seasonal variation in the landcover – snow cover in particular can vary dramatically over periods of weeks to months – and the satellite orbits have particular features which are not generally significant at lower latitudes. It is unlikely that natural scatterers will be stable over long periods in these areas. The aim of this project is to develop methods of SAR interferometry suitable for use in landscapes with seasonal snow cover. The project has two themes: (1) improved understanding of SAR imaging at high latitudes and the use of interferometry in such landscapes, and (2) the development of artificial radar targets which can provide the necessary stability for long-term surface deformation monitoring. The sponsor runs a large mining operation at high latitudes. The study has a practical focus and is part of a larger project to provide a mining subsidence monitoring service for the sponsor. The project’s aim is to achieve accurate monitoring of subsidence using radar interferometry at high latitudes. Techniques developed should be suitable for operational use. Test site The experiment test site is centred on the town of Kiruna in northern Sweden (67° 51’ N, 20° 13’ E). The ground is covered with snow (to a depth of 1 m or more) from October to May each year, and so the winter and summer periods have very different land cover properties. The site includes the town of Kiruna, a large mine, and areas of natural sparse forest with mainly birch and some coniferous trees up to several metres tall. Datasets Available Several datasets are available to support the research, these include: • GPS measurements from a network of control points • General weather observations • Mapping data for land cover / land use and topography • SAR images at approximately monthly intervals from 2009 (Radarsat-2, using up to 3 satellite tracks for imaging) • A network of corner reflectors across the test area The core data analysis tool is the MDA software package designed for processing Radarsat images (for both backscatter and interferometric products). The key resource for the research is the time series of high resolution SAR images suitable for interferometric processing, which allows seasonal changes in backscatter to be observed directly. Methodology The project requires a mix of simulation and practical design and fieldwork. The main contributions will be in the area of target specification, design and validation. Achievements to date The project started late in 2009 and the main emphasis so far has been to establish the datasets needed for the research. Radarsat-2 images have been acquired and are being processed to derive interferometric products and to register them to standard projections compatible with each other and ancillary data. Field observations complementing the satellite imaging are also being made. Acknowledgements The project is sponsored in full by the LKAB mining company.The project also benefits from technical advice of MDA.

HSV kategori
Forskningsprogram
Industriell elektronik
Identifikatorer
urn:nbn:se:ltu:diva-39424 (URN)e2ee2478-d6aa-4aad-ade1-52c1282b4812 (Lokal ID)e2ee2478-d6aa-4aad-ade1-52c1282b4812 (Arkivnummer)e2ee2478-d6aa-4aad-ade1-52c1282b4812 (OAI)
Konferanse
International Workshop on "Advances in the Science and Applications of SAR Interferometry" : FRINGE 2011 Workshop 19/09/2011 - 23/09/2011
Merknad
Godkänd; 2011; 20111205 (tore)Tilgjengelig fra: 2016-10-03 Laget: 2016-10-03 Sist oppdatert: 2017-11-25bibliografisk kontrollert
Organisasjoner