• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.847-860
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• 2020

The 2-pass DInSAR (Differential Interferometric SAR) processing steps for DEM generation consist of the co-registration of SAR image pair, interferogram generation, phase unwrapping, calculation of DEM errors, and geocoding, etc. It requires complicated steps, and the accuracy of data processing at each step affects the performance of the finally generated DEM. In this study, we developed an improved method for enhancing the performance of the DEM generation method based on the 2-pass DInSAR technique of TanDEM-X bistatic SAR images was developed. The developed DEM generation method is a method that can significantly reduce both the DEM error in the unwrapped phase image and that may occur during geocoding step. The performance analysis of the developed algorithm was performed by comparing the vertical accuracy (Root Mean Square Error, RMSE) between the existing method and the newly proposed method using the ground control point (GCP) generated from GPS survey. The vertical accuracy of the DInSAR-based DEM generated without correction for the unwrapped phase error and geocoding error is 39.617 m. However, the vertical accuracy of the DEM generated through the proposed method is 2.346 m. It was confirmed that the DEM accuracy was improved through the proposed correction method. Through the proposed 2-pass DInSAR-based DEM generation method, the SRTM DEM error observed by DInSAR was compensated for the SRTM 30 m DEM (vertical accuracy 5.567 m) used as a reference. Through this, it was possible to finally create a DEM with improved spatial resolution of about 5 times and vertical accuracy of about 2.4 times. In addition, the spatial resolution of the DEM generated through the proposed method was matched with the SRTM 30 m DEM and the TanDEM-X 90m DEM, and the vertical accuracy was compared. As a result, it was confirmed that the vertical accuracy was improved by about 1.7 and 1.6 times, respectively, and more accurate DEM generation was possible with the proposed method. If the method derived in this study is used to continuously update the DEM for regions with frequent morphological changes, it will be possible to update the DEM effectively in a short time at low cost.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.535-542
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• 2011

We extracted a surface displacement map of Canisteo Peninsula and the surrounding area in West Antarctica by applying 4-pass DInSAR technique to two ERS-1/2 tandem pairs and analyzed the surface displacement of glaciers and sea ice. In the displacement map, glaciers showed fast motion pushing the adjoining land-fast sea ice which has the displacement in the same direction as the glacier. Cosgrove ice shelf showed large displacement pushing the adjoining land-fast sea ice as well. Some sea ice indicated the displacement that is opposite to the land-fast sea ice. This was because the type of the sea ice is drift ice that is affected by ocean current. Therefore, we could confirmed the boundary between land-fast sea ice and drift ice. It was difficult to distinguish ice shelf from ice sheet because they showed similarities both in brightness of the SAR images and in fringe rates of the interferograms. However, a boundary between fast-moving ice shelf and stable ice sheet was easily confirmed in the displacement map after the phase unwrapping process.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.190-195
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• 2009

서남극 빙상의 감소 속도는 급격히 가속화되고 있으며, 전 지구적 해수면 상승과 기후변화 예측을 위해 이 지역에 대한 지속적인 관찰이 요구되고 있다. 본 연구에서는 서남극 Canisteo 반도와 주변 지역이 촬영된 2쌍의 ERS-1/2 tandem pair에 4-pass 위상차분간섭기법을 적용하여 위상차분간섭도를 생성하였고, 빙하와 해빙, 그리고 빙붕의 표면 변화를 관찰하였다. 위상차분간섭도에서 센서 방향으로의 변위를 추출한 결과 해안 빙하와 그에 인접한 정착빙은 같은 방향의 움직임을 나타냈다. 특히 빙하와 맞닿은 부분의 정착빙은 그 움직임이 다른 부분에 비해 컸는데, 이는 빙하의 하강 및 유실이 해빙에 영향을 끼치는 것으로 판단된다. 정착빙의 가장자리에 위치한 해빙은 해류의 영향에 기인하는 움직임을 보였으며, 이 해빙의 유형이 부빙 또는 유빙임을 알 수 있었다. 반도 양옆에 위치한 빙붕은 모두 센서 방향으로의 움직임을 보였으나 그 크기에서 차이를 나타냈다. 빙붕의 표면에서는 원형의 국부적 함몰이 다수 관찰되었는데, 이는 남극저층수의 적은 유입으로 인해 형성된 melt pond로 추정된다.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.414-417
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• 2008

We have extracted a surface deformation map of a part of Canisteo Peninsula on Amundsen Sea in West Antarctica by applying 4-pass DInSAR technique to two ERS-1/2 tandem pairs obtained on October 21-22, 1995 (diff-pair) and March 9-10, 1996 (topo-pair), and analyzed changes of glaciers, sea ice, ice shelves, and their kinematic interactions. We observed fast motion of glaciers pushing the adjoining sea ice. Some interferometric phases indicate the up-rise of sea ice of which type is thought to be land-fast ice to exert repulsive force against the pushing glacier. There were other glaciers and sea ice that moved to the same direction, suggesting that the sea ice in these regions was land-fast ice weakly harnessed to sea bottom or pack ice not harnessed at all. Several small circular fringes in ice shelves suggested that islands or seamounts on the bottom of ice shelves deterred the movement of ice shelves, resulting in the rise of ice surface.