Interpretation of Remote Sensing Data of Pipeline Geohazards

For natural gas pipelines across the area in southwest China(2470km
²
), the small baseline subset SAR interferometry (SBAS-InSAR) and the differential InSAR (D-InSAR) are used to acquire the deformation information of the entire area from 2016-07 to 2021-21 based on the image data of Sentinel-1A and ALOS-2 high-resolution synthetic aperture radar (SAR). The results show that InSAR technology, as an emerging technical means of monitoring pipeline geohazards, can be used to monitor wide-area surface deformation, providing significant technical support for pipeline geohazard prevention and control. SBAS-InSAR can be used in the comparison between ALOS-2 data and Sentinel-1 data for pipeline geohazard prevention. The overall quality of ALOS-2 data interferogram is better than that of Sentinel-1 data, especially in areas covered by vegetation, the former can keep a fair coherence and have a higher resolution. For the analysis of pipeline geohazards in a wide area, it is recommended to adopt the block division by the same type according to the terrain trend. In addition to that, key areas can be divided into smaller blocks. In the analysis of InSAR data, the time series for analysis can be appropriately lengthened when the SBAS-InSAR technology is used. For areas with poor coherence and small hazard points, wavelet filtration shall be adopted to prevent effective coherent points from being masked; In areas with higher coherence, filtration shall be properly strengthened to eliminate error noise. A same area shall be divided into small blocks for InSAR identification, by which the results will be more accurate than that by the whole-area identification, and the small blocks shall be preferably between 50-130 square kilometers.