Hybrid polarimetry inverse synthetic aperture radar

Abstract

The inverse synthetic aperture radar (ISAR) system exploits the movement of the target to form its high-resolution image. Further, the multi-polarisation acquisition in ISAR collects additional information on the target's scattering properties and surface characteristics that help to enhance the imaging capabilities of ISAR. In this study, we suggest a novel multi-polarisation ISAR configuration based on the circular transmit and linear receive (CTLR) combination, namely CTLR hybrid-pol ISAR, for the application of non-cooperative target detection and imaging. The CTLR hybrid-pol ISAR captures sufficient information about the targets to accurately characterise them, and simultaneously overcomes the drawbacks of full-polarimetry (full-pol) ISAR associated with the transmission of two pulses to obtain a single unit of polarimetric back-scattered information. Validation is performed using real ISAR data of a T-72 tank target, collected under the moving and stationary target acquisition and recognition (MSTAR) programme conducted by the Georgia Tech Research Institute. A comparative analysis based on SPAN, entropy, and polarimetric decomposition is carried out between the full-pol ISAR and CTLR hybrid-pol ISAR information. The results conclude that CTLR hybrid-pol ISAR maintains a similar level of information content compared to full-pol ISAR while overcoming its drawbacks.