Accuracy Assessment of High-Resolution DEM Generation Using Bistatic and Tomographic InSAR: A Comparative Study

High-resolution digital elevation models (DEMs) are fundamental geospatial products that support a wide range of applications, including hazard monitoring, hydrological modeling, urban planning, and geological investigation. Interferometric synthetic aperture radar (InSAR) has become one of the most important techniques for large-scale DEM generation due to its all-weather capability and high vertical sensitivity. In recent years, two advanced InSAR techniques—bistatic InSAR and tomographic InSAR (TomoSAR)—have been increasingly adopted for high-resolution terrain reconstruction. While both approaches are capable of generating detailed elevation information, their relative performance, accuracy characteristics, and practical limitations under different terrain conditions remain insufficiently quantified.This study presents a systematic accuracy assessment and comparative evaluation of high-resolution DEMs generated using bistatic and tomographic InSAR techniques. Using representative mountainous and urban test sites, DEM products derived from bistatic InSAR and TomoSAR are quantitatively evaluated against reference airborne LiDAR data. Statistical indicators including root mean square error (RMSE), mean absolute error (MAE), bias, and spatial autocorrelation of residuals are employed to measure vertical accuracy and spatial consistency. The results demonstrate that bistatic InSAR provides highly stable and efficient elevation reconstruction over open and moderately rugged terrains, while TomoSAR exhibits superior performance in complex urban areas and densely vegetated mountain slopes where layover and volume scattering dominate. The comparative analysis highlights the complementary advantages of the two techniques and provides practical guidance for selecting appropriate InSAR configurations for high-resolution DEM production.