A Novel Method for Airborne SAR Tomography Baseline Error Correction Driven by Small Baseline Interferometric Phase

Baseline error correction is critical for airborne synthetic aperture radar (SAR) tomography as the actual flight trajectory often deviates from the designed one due to turbulence, which may lead to large sidelobes or even complete defocusing in the tomograms. Current baseline error correction methods, however, are susceptible to heavy decorrelation noise. To mitigate the adverse effect of decorrelation noise, in this article, a novel method for airborne SAR tomography baseline errors correction driven by small baseline interferometric phase is proposed. In this method, a novel mathematical model that relates interferometric phase to the baseline error differences is first derived; then, a small baseline interferometric pairs selection strategy is employed to estimate the baseline error differences through an alternate iterative algorithm, and finally, the baseline errors are obtained through accumulating summation of the baseline error differences. The use of small baseline interferograms can avoid the phase linking processing and thereby greatly alleviate the heavy decorrelation effect. Both simulated and real airborne P-band SAR tomography experiments have demonstrated that the proposed method can achieve more accurate and robust estimation of baseline errors and is more tolerant to decorrelation noise than the well-known phase center double localization (PCDL) method.