On the use of permanent symmetric scatterers for ship characterization

TLDR

SSCM, a high‑resolution method based on a Poincaré/spl‑acute/sphere representation, was recently introduced to decompose symmetric target scattering and assess backscatter coherence under coherent conditions. This study applies SSCM to ship characterization using Convair‑580 polarimetric SAR data. The authors estimate ship pitch from the polarization‑orientation angle of quasi‑symmetric scatterers and evaluate SSCM sensitivity to SAR focus‑setting and Doppler‑centroid errors, showing that first‑order error effects can be removed before applying the method. SSCM successfully identifies dominant scatterers with significant symmetric components, but its performance is affected by focus‑setting and Doppler‑centroid shifts, which can be mitigated by correcting first‑order errors.

Abstract

The symmetric scattering characterization method (SSCM) has been recently introduced for high-resolution characterization of certain targets under coherent conditions. SSCM is based on the Poincare/spl acute/ sphere representation, which supports a high-resolution decomposition of symmetric target scattering, as well as assessment and validation of the backscatter coherence. In this paper, the SSCM is investigated for ship characterization using Convair-580 polarimetric synthetic aperture radar (SAR) data. It is shown that the target Poincare/spl acute/ parameters permit identification of dominant scatterers with a significant symmetric scattering component. The polarization orientation angle of these quasi-symmetric scatterers is used to derive an estimate of the ship's pitch angle, under certain conditions. The effect of SAR system focus setting errors and Doppler centroid mistracking on the SSCM performance is investigated. It is shown that the SSCM is sensitive to the system focus setting and Doppler centroid shift. The first-order effects of these errors can be removed prior to the application of the SSCM method.