Interferometric Calibration and Verification in LuTan-1 to Ensure the Global Digital Elevation Quality

Abstract:
The LuTan-1 (LT-1) mission consists of two L-band SAR satellites and is China’s first bistatic spaceborne SAR mission for civil applications. In the bistatic InSAR strip map mode, two satellites fly in formation with a variable baseline to acquire global digital elevation models (DEMs) with high accuracy and spatial resolution. Interferometric calibration is essential for identifying systematic errors that facilitate the production of high-precision DEMs. However, issues unique to the bistatic system LT-1, such as interferometric parameter coupling and the π-ambiguity problem caused by synchronization phase error, have not been resolved. This research creates an interferometric calibration model for LT-1 to address the above issues. A pair of SAR images and eight deployed corner reflectors are utilized for interferometric calibration, and the calibrated interferometric parameter errors are compensated by two additional interferograms acquired at separate beams and days to generate DEM for interferometric calibration model validation.