1. 1Mines-Telecom Institute, Mines Douai, 941, rue Charles Bourseul, BP 10838-59508, Douai Cedex, France
2. 2Polytechnic University of Catalonia, Automatic Control Department, Jordi Girona, 31-08034-Barcelona, Spain
3. 3Service de la navigation du Nord Pas-de-Calais, Voies Navigables de France, 37 rue du Plat, BP 725, 59034 Lille Cedex, France