自 2014年以來，歐洲太空總署之哥白尼地球觀測計畫致力於提供無償衛星影像，其中 Sentinel-1 雷達衛星之C波段合成孔徑雷達(SAR)提供週期性再訪的連續圖像，對於地表變遷可透過相位變化解算視衛星方向地表變形，再利用地面GNSS站約制可獲得三維方向地表活動。結合Sentinel1-A/B兩顆衛星平均每六天再訪週期，可提供季節性於年際間的變化。臺灣西南部之地表變遷複雜且迅速，包含板塊移動、地震活動與地層下陷等，需透過時空上密集監測以獲得整體區域性的相對位移。點狀GNSS連續接收站雖提供高精度三維速度，然而維護不易且僅能提供片段、離散資料，對於細部的地表差異變化力有未逮，因此需透過面狀遙測影像填補空缺，同時節省人力與物力的消耗。因此本研究擬利用自2014年起Sentinel-1系列之Interferometric Wide Swath (IWS)模式感測Single Look Complex (SLC)低階影像，建構半自動化處理流程產製短基線差分干涉(Small Baseline Subset DInSAR)時序位移地圖，針對西南平原提供即時更新的地表位移。 ;Since 2014, Sentinel-1 of European Space Agency started providing cost-free C-band SAR images for land surveillance. The 12-day revisit cycle helps us to understand the line-of-sight motion of ground surface through phase interferometry. The land motion in southwest Taiwan is complicated as it is an integrated effect of tectonics, earthquakes, and land subsidence. It requires a synoptic view of relative motion from spatial-temporally densified observations. GNSS continue stations are helpful for revealing three-dimensional movement of the land in point locations. However, a wide coverage of land monitoring is needed perhaps by the technology of synthetic aperture radar (SAR) routine swaths. This project intends to utilize historical and newly updates of Sentinel-1 Single Look Complex (SLC) imageries to automatically produce Small Baseline Subset Differential SAR Interferometry (SBAS DInSAR). It could detail the relative motion of southwest alluvial plain and help on understanding the land subsidence and activity of faults.
