Sensors_**2008**, 8, 7715-7735; DOI: 10.3390/s8127715  
_Article_  
**Assessment of Polarimetric SAR Interferometry for Improving Ship Classification based on Simulated Data**  
**[PERSON] \({}^{1,2,\star}\) and [PERSON] \({}^{1}\)**  
1 Remote Sensing Laboratory, UPC, C [PERSON], 1-3, Campus Nord, E-08034, Barcelona, Spain  
E-mail: [EMAIL_ADDRESS]. 2 GMV Aerospace and Defense, S.A., C Balmes, 268-270, 5 th floor, E-08006, Barcelona, Spain  
\({}^{\star}\) Author to whom correspondence should be addressed; E-mail: [EMAIL_ADDRESS]. _Received: 16 June 2008; in revised form: 17 November 2008 / Accepted: 27 November 2008 / Published: 2 December 2008_  
**Abstract:** This paper uses a complete and realistic SAR simulation processing chain, GRECOSAR, to study the potentialities of Polarimetric SAR Interferometry (POLInSAR) in the development of new classification methods for ships. Its high processing efficiency and scenario flexibility have allowed to develop exhaustive scattering studies. The results have revealed, first, vessels' geometries can be described by specific combinations of Permanent Polarimetric Scatterers (PePS) and, second, each type of vessel could be characterized by a particular spatial and polarimetric distribution of PePS. Such properties have been recently exploited to propose a new Vessel Classification Algorithm (VCA) working with POLInSAR data, which, according to several simulation tests, may provide promising performance in real scenarios. Along the paper, explanation of the main steps summarizing the whole research activity carried out with ships and GRECOSAR are provided as well as examples of the main results and VCA validation tests. Special attention will be devoted to the new improvements achieved, which are related to simulations processing a new and highly realistic sea surface model. The paper will show that, for POLInSAR data with fine resolution, VCA can help to classify ships with notable robustness under diverse and adverse observation conditions. **Keywords:** POLInSAR, Ship Classification, SAR Simulation, Coherent Target Decompositions. Introduction  
The GRaphical Electromagnetic COmputing SAR (GRECOSAR) simulation tool has been developed at UPC [1; 2]. The possibility to process any complex geometry within flexible and totally controlled scenarios has provided a new benchmark for carrying out a set of SAR research activities that are difficult to be done with real data. Examples are exhaustive scattering studies where the dispersion behavior of targets is evaluated for the widest range of observation conditions possible or performance tests where current and/or new sensor designs are evaluated according to particular specifications. GRECOSAR has been designed to deal with any type of SAR sensor operating at any band, resolution and mode with polarimetric and interferometric capabilities. Its processing efficiency is high and only needs from a simple PC to process realistic and highly detailed 3D models. Up to now, two main types of scenarios with dielectric materials can be managed: maritime and urban. The former is very realistic as ship motions, bearing and velocity are considered as well as a surrounding dynamic sea. GRECOSAR has been mainly used for scattering studies of complex targets. Most of the efforts have been focused to ships for which few information about their dispersion characteristics was available. This is essential for developing more efficient scattering-based classification methods that can fulfill the new monitoring demands for SAR imagery (see IMPAST [3] and DECLIMS [4] projects). In this framework, a large number of polarimetric scattering maps with resolutions around centimeters have been generated for different ship geometries and environmental parameters. Their analysis with Coherent Target Decompositions (CTD) [5; 6] have revealed certain dispersion stability along the radar aspect angle.