Radar sea surface modeling and simulation

Abstract

This work is a significant part of the MODENA project, aiming at modeling and simulating the maritime environment remotely sensed by a radar [1].The main steps of the project go through a modeling of the ocean surface, the man-made objects on the surface as well as of the interaction between the electromagnetic waves with this surface and the objects. One of the main interests of the radar simulation is SAR imaging. Usually SAR imaging is directly simulated from a sea spectrum, through an appropriate transfer function. The drawback of this method is the impossibility to simulate a phenomenon whose size is inferior to the SAR resolution. The methodology developed in this paper is different since the simulation is done before SAR processing. By choosing to simulate the backscattered field toward the radar antenna, it is then possible to define the scene mesh independently of the final SAR image resolution. Furthermore the use of irregular mesh provides opportunities to focus more finely on specific phenomena locally defined. The simulation principle was explained in [6]. It consists of reproducing the acquisition of a Real Aperture Radar (RAR) moving along an axis. An important part of the simulation is the generation of the sea surface. It is achieved by a multi-scale model whose description is given in [2] and [3]. This model gives the possibility to manage and represent dynamically the maritime environment at different scales: large scale for the long waves of the sea surface (swell-like); short scale for small waves (wind-driven ones). To improve the processing time some contributions can also be retrieved from Look-Up Tables. Hence, our method performs a realistic simulation of electromagnetic interactions in a maritime environment. This paper will focus on the results obtained from the theoretical and practical developments achieved since the description given in [4] at last year conference.