Contaminated water surface RCS measurements in basin over very wide frequency band

Autor: Mainvis, Aymeric, Borderies, Pierre, Fabbro, Vincent, Monvoisin, Jean-Pascal, Garrigues, Quentin, Miegebielle, Véronique
Přispěvatelé: ONERA / DEMR, Université de Toulouse [Toulouse], ONERA-PRES Université de Toulouse, TotalFinaElf-CSTJF/Pau, TotalFinaElf
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: SELPER 2018
SELPER 2018, Nov 2018, LA HAVANE, Cuba
Popis: International audience; It is well known the presence of oil films over sea surface may be detected on radar images by a decrease of the backscattering coefficient due to a change of roughness state. The paper proposed here consists in proximity experiments for the measurements of the water surface backscattering coefficient over a very wide frequency band with a mastered wind strength and spreading of various kinds of oil and hydrocarbons to better apprehend this phenomenon and to investigate if not only detection but also characterization of the film can be envisaged. To obtain a homogeneous incidence angle over the scene of interest, it was proposed to work in the near field, tubular zone of a large reflector where the radiated wave is nearly plane. For this purpose, an offset parabolic reflector with 40 cm diameter was used. The primary source of the reflector is a very wide band dual polarization horn. The emitter receiver is a Vector Network Analyser with very high sampling rate and very short commutation time. The antenna is fixed on a positioning system driving the direction of observation both in azimuth and elevation. A blower of high power generates the surface roughness of the clean water surface which is in turn affected by the presence of oil and consequently on the radar backscattering coefficient. Each measurement of continuous oil spreading covers a frequency band of 2-22 GHz with 20000 intervals and the three polarizations HH, VV and HV for 500 realizations.First part of the presentation will describe the experimental set-up which has been implemented and the method of measurement and derivation of sigma0, with particular emphasis on the acquisition time constraints and calibration. Second part will present the measurements themselves and some first results obtained.
Databáze: OpenAIRE