Abstract
The number of successful missions with autonomous underwater vehicles (AUVs) has been increasing steadily during the last few years, validating this emerging technology as an e cient tool for underwater sampling. At the same time it has served to envisage their operation in more demanding scenarios. This paper presents results from environment monitoring missions with an AUV and new mission concepts for the operation of one or multiple AUVs. These new concepts are the natural evolution of previous work and also the response to the requirements of some of the identi ed scenarios. For each type of mission, solutions for navigation, control, coordination, and communications are presented. © 2004 IFAC

Abstract
This paper presents the recent developments of the project Multiple Autonomous Underwater Vehicles for Coastal Oceanography, of the University of Porto. The project envisages the development of a highly operational and low-cost system for scientific and environmental data collection in the Portuguese coastal waters. The project activities suggested the development of a Generalized Vehicle (GV) Control Architecture for multiple vehicles. Reconfigurability, reliability and operational effectiveness, are at the basis of this control architecture, which encompasses human intervention besides the cooperation among AUVs and other system devices. A simulation environment was developed in SHIFT, to support the design and testing of the GV control architecture. SHIFT is a new specification language for describing dynamic networks of hybrid automata, which constitute the most adequate formalism for this problem domain.

Abstract
In this paper, we present a low-cost versatile device developed to support the navigation of autonomous underwater vehicles. Unlike the usual transponders extensively used for LBL acoustic navigation of a single vehicle, this device allows the navigation of multiple vehicles and the remote tracking of their positions, without any extra acoustic signals being transmitted. The navigation beacon has a radio buoy connected to an underwater reconfigurable multi-frequency transponder. A remote tracking station receives data from the buoy and monitors the position of the vehicles in real time. We describe the mechanical, electronic and software modules involved, as well as the tracking algorithm, and we also present experimental data from an operational mission.

Abstract

Abstract
In this paper, we address the current developments of the "PISCIS" project. We focus on the experimental results from recent operational missions with an AUV in a estuarine environment. Besides describing mission planning and logistic details, we also present tools for oceanographic data processing and visualization. This will be demonstrated with some examples of collected data.

Abstract
This paper describes the interaction between the kinematic model of the AUV MARES, and the measurement and observation of the environment through images obtained with the sonar use. Three types of Sonar are discussed in this paper; there are forward-look, side scan and multibeam. But the sonar used to develop this work was the side scan sonar. The type of observations and characteristics of the environment provided by the sonar are described here. The method, which connects the sensory part of the vehicle with the observations of the sonar, was the Kalman filter (EKF). In this paper, are presented two simulations of filters for two different characteristics. Both filters estimate the characteristics of natural landmarks, creating an environment map, but both of them consider different states of the vehicle. Results of the simulation are obtained. The features that are considered are an underwater pipe on the floor and a wall. It also generated a control for the vehicle that provides the capacity to move along the feature/landmark from a reference distance.