Gridless GLRT Approach for Polarimetric SAR Tomography

Tomographic synthetic aperture radar is a fundamental imaging technique for urban environments' mapping and monitoring. Yet, its performance is often limited by the discrete height grid used in conventional reconstruction methods, leading to off-grid errors and biased estimates. While recent gridless approaches based on the generalized likelihood ratio test (GLRT) have successfully mitigated these gridding artifacts, achieving superresolution and improved height accuracy, they remain confined to single-polarization data. The aim of this study is to fill in this gap by introducing a gridless polarimetric GLRT detector. The proposed method operates in the continuous elevation domain and formulates a statistical test that optimally fuses information from multiple polarimetric channels. The proposed detector was rigorously validated using both simulated data and real TerraSAR-X dual-polarimetric acquisitions. The results demonstrate a consistent and significant performance gain over state-of-the-art methods, including grid-based polarimetric detectors and single-polarization gridless detectors, manifesting as superior height estimation accuracy, a marked reduction in false alarms, and an enhanced ability to resolve closely spaced scatterers in complex urban layover.