Generation Of Digital Elevation Models By Using Space-Borne Synthetic Aperture Radar Interferometry

Digital elevation model (DEM) is the fundamental infrastructure of geographical information systems and has wide applications in both military and civil areas. As a powerful earth-observation technique, synthetic aperture radar interferometry (InSAR) is thought as one of the effective techniques for obtaining large-area and high-quality DEMs. Under the support of Sino-Euro cooperative project—ANFAS, this dissertation studies thegeneration of DEMs using space-borne InSAR.With the aim of obtaining high-quality DEM, this dissertation studies the fundamental theory and processing techniques of space-borne repeat-tracking interferometry, and generates DEM of Jing-Jiang retention using ERS-1/2 tandem data. Main works are included as follows:1. Based on the statistical properties of interferometric phases (IP), the effects of coherence and looks on IP are discussed and an unbiased estimation method of the IP and coherence is proposed with the combination of complex coherence and multi-look processing.2. Under the discussion of IP decorrelation, a thorough analysis is conducted of generating mechanisms of baseline decorrelation and Doppler decorrelation and their effects on IP. By using ERS-1/2 data, spectrum-shift filtering scheme in both range and azimuth directions is implemented. With the coherences as the judgment of IP qualities, it is shown that the spectrum-shift filtering can remove the decorrelation and thus improve the IP quality.3. The alias effects caused by complex-conjugate multiplications on IP quality are analyzed. With the coherence and residuals as the judgment, the performances of re-sampling techniques for removing alias effects are discussed by using ERS-1/2 data and it is pointed out that the over-sampling techniques can greatly improve IP quality.4. The physical meanings of flat-earth phases are thoroughly discussed and the concepts of flat-earth phases and relative flat-earth phases are established. It is proved that the spectrum-shift method can only remove relative flat-earth phases. A geolocation-based method is proposed to remove flat-earth effects.5. The effect of baseline on InSAR system is discussed. With comparisons of several...