Effects of centre-beam approximation on airborne repeat-pass interferometric SAR

The center-beam approximation (CBA) in the conventional two-step motion compensation (MOCO) has been one of crucial factors for the high-precision airborne synthetic aperture radar (SAR) data processing, especially for the airborne repeat-pass interferometric SAR (InSAR), where the effects of the residual motion errors on the phase don´t cancel out during generating interferogram. In this paper, a useful approach, evaluating the effects of CBA on the airborne repeat-pass InSAR quantitatively, is proposed based on their transfer functions. The dependence of the resulting correlation coefficient and the phase bias on the different system parameters and the processing parameters is showed in several diagrams. The research provides theoretical bases for the MOCO precision in signal processing of airborne repeat-pass InSAR.