Robust PolInSAR optimal interferogram estimation method based on generalized scattering vector

For the polarimetric synthetic aperture radar interferometry(PolInSAR) processing, it is necessary to coregister all the images, including the coregistration of polarimetric SAR images and the coregistration of interferometric SAR images. Otherwise,the performance of the estimated optimal interferograms will be deteriorated. A generalized scattering vector(GSV) model is proposed to execute the PolInSAR optimal interferograms estimation.The generalized scattering vector is constructed by the Pauli scattering vectors of the processing pixel and the surrounding pixels.Even though there are coregistration errors, all the polarimetric information of the current processing pixel is entirely included in the generalized scattering vector. Therefore, the GSV-based method can automatically recover the optimal scattering mechanisms of the processing pixel with coregistration errors either in interferoemetric channels or polarimetric channels. Theoretical analysis and processing results of simulated Pol SARPro data and real PALSAR data validate the effectiveness and correctness of the proposed method.

Azimuth resolution improvement for spaceborne SAR images with quasi-non-overlapped Doppler bandwidth

The azimuth resolution improvement problem is solved via a coherent combination of synthetic aperture radar(SAR) images with the quasi-non-overlapped Doppler bandwidth. Prior to the spectra combination, SAR images should be co-registered, while phase biases induced by topography, atmospheric propagation delays and baseline measurement errors should be calibrated. However, the coregistration accuracy suffers from large Doppler decorrelation caused by the quasi-non-overlapped Doppler bandwidth. Furthermore, the method used to estimate phase biases from interferogram of azimuth pre-filtered SAR image pairs will fail when there is no overlapped spectrum. The fringe simulation and maximum sharpness optimization are adopted to deal with the problems. Accordingly, a novel algorithm to coherently synthesize SAR images is presented. The experiment with the Terra SAR X-band(TerraSAR-X) satellite data validates the performance of the presented method.