Influence of different DEMs on the quality of the InSAR results: case study over Bankya and Mirovo areas

Hristo Nikolov; Mila Atanasova

doi:10.1117/12.2278393

3 October 2017 Influence of different DEMs on the quality of the InSAR results: case study over Bankya and Mirovo areas

Hristo Nikolov, Mila Atanasova

Proceedings Volume 10426, Active and Passive Microwave Remote Sensing for Environmental Monitoring; 104260M (2017) https://doi.org/10.1117/12.2278393
Event: SPIE Remote Sensing, 2017, Warsaw, Poland

Abstract

One of the key input parameters in obtaining end products from SAR data is the DEM used during their processing. This holds true especially when persistent scatterers InSAR method should be applied for example to study slow moving landslides or subsidence. Since nowadays most of the raw SAR data are of space borne origin for their correct processing to high precision products for relatively small areas with centimeter accuracy a DEM taking into account the particularities of the local topography is needed. Most of the DEMs used by the SAR processing software such as SRTM or ASTER are obtained by the same type of instrument and present some disagreements with height information acquired by leveling measurements or other geodetic means. This was the motivation for initiating this research – to prove the need of creating and using local DEM in SAR data processing at small scale and to check what the magnitude of the discrepancy between final InSAR products is in both cases where SRTM/ASTER and local DEM has been used. In addition investigated were two scenarios for SAR data processing – one with small baseline between image pairs and one having large baseline image pairs – in order to find out in which case local DEM has bigger impact. In course of this study two reference areas were considered – Bankya village near Sofia (SW region of Bulgaria) and Mirovo salt extraction site (NE region of Bulgaria). The reason those areas were selected lies in the high number of landslides registered and monitored by the competent authorities in the mentioned locations. The significance of the results obtained is witnessed by the fact that both sites we used have been included as reference sites for Bulgaria in the PanGeo EU funded project dealing with delivering information regarding ground instability geohazard as areas prone to subsidence of natural and manmade origin. In the said project largest part of the information has been extracted from Envisat SAR data, but now this information could be supplemented by adding such from Sentinel-1 derived by us. During this research two local DEMs have been extracted from the tiles including the areas of investigation, one using SRTM data and one from ASTER, and after this procedure both were compared to the DEM gathered by leveling measurements. Finally conclusions are drawn and a direction for future research steps is provided.

Citation Download Citation

Hristo Nikolov and Mila Atanasova "Influence of different DEMs on the quality of the InSAR results: case study over Bankya and Mirovo areas", Proc. SPIE 10426, Active and Passive Microwave Remote Sensing for Environmental Monitoring, 104260M (3 October 2017); https://doi.org/10.1117/12.2278393

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