A Comparative Study of DEM Reconstruction Using the Single-Baseline and Multibaseline InSAR Techniques

Interferometric SAR (InSAR) is a practical technique to derive three-dimensional information of the earth surface. This paper conducted a comparative study of DEM reconstruction using the single-baseline and multi-baseline InSAR techniques. To improve the accuracy of the DEM generated from the single-baseline InSAR, we improved the weight definition approach according to the coherence coefficients for the fusion of single-baseline InSAR DEMs. For multi-baseline InSAR, we adopted a method based on the Maximum Likelihood Estimation (MLE) algorithm which uses external DEM as constraint. A TerraSAR-X dataset comprising four SAR images over Barcelona was used for experimental investigation. The accuracies of four types of DEM are comparatively studied, including DEM by single-baseline InSAR, DEM by the fusion of single-baseline InSAR DEMs, DEM by unconstrained multi-baseline InSAR, and DEM by constrained multi-baseline InSAR. The results showed that the proposed weighted fusion of single-baseline InSAR performed a little better than the constrained multi-baseline InSAR method, and both of them performed better than the single-baseline results, demonstrating that multiple observations can effectively improve the accuracy of the reconstructed DEM.