Abstract:In 2022, China launched two L-SAR satellites, which opened a new era of large-scale application of domestic interferometric SAR satellites. Large-scale topographic measurement is an important application direction of interferometric SAR satellites, and reference DEM is indispensable and important data in the process of topographic interferometric measurement. Purpose: How to select reliable reference DEM to meet different topographic measurement requirements is an urgent problem to be solved in the use of InSAR technology to extract DEM. Method: This paper selects ASTER GDEM, AW3D30 DEM, SRTM DEM, and Copernicus DEM as reference DEMs respectively, and uses two scenes of domestic L-SAR satellite images in 2023 to carry out DEM data extraction in a certain region of Henan Province using InSAR technology. ICESat-2 laser altimetry data is used as the true elevation value, and the mean square error is used as the evaluation index to test the elevation accuracy. Result: When using Copernicus DEM as the external reference DEM, the LT-DEM elevation accuracy is the highest under different terrain conditions, followed by SRTM DEM, AW3D30 DEM, and ASTER GDEM. Conclusion: 1) L-SAR satellite has the ability of wide-area efficient topographic mapping and high topographic inversion accuracy; 2) When using InSAR technology to process L-SAR images, using Copernicus DEM as the reference data obtains higher DEM elevation accuracy; 3) The elevation accuracy of extracting DEM using InSAR technology is affected by terrain factors, with low elevation accuracy in mountainous areas and high elevation accuracy in plains. This experiment extracts DEM using 12-meter domestic L-SAR images for the first time, innovatively using four reference DEM data with the same spatial resolution for InSAR processing, and compares and analyzes the performance of the four reference DEMs. Significance: This experiment provides guidance for extracting different topographic DEMs using InSAR technology, which can help topographic surveyors better choose external reference DEMs when processing InSAR images, and provide an important work basis for geological disaster monitoring, mineral development, land use, and other types of work.