Abstract
This paper presents a custom processor designed to execute a time consuming function in a CFD application. The selected function implements the method TDMA (Tri-Diagonal Matrix Algorithm) for solving a tri-diagonal system of equations. The custom processor was implemented in a commercial PCI prototyping board based on Virtex4LX FPGAs and uses a dedicated memory cache system, address generators and a deep pipelined floating-point datapath. Running at 100MHz and assuming the input data already in the cache memories, the system reaches a throughput greater than 1.4GFLOPS.

Abstract
Height mapping of shallow water areas is an important task for many commercial and scientific applications like river navigability, infrastructure maintenance or natural resource monitoring. The use of an autonomous boat presents several advantages that case the use of synthetic aperture images to create three-dimensional topographic maps through interferometric techniques. Sample data obtained during test trials illustrate how synthetic aperture can be used to generate imagery and bathymetry data.

Abstract
In this paper, we discuss the design aspects and the development of the MARES AUV, a 1.5m long vehicle, weighting 32kg, designed and built at the University of Porto, Portugal. This vehicle is highly maneuverable, with the ability to move in the vertical plane, controlling pitch and vertical velocity; forward velocity can also be determined, anywhere between 0 and 2 m/s. MARES can easily integrate any new payload within reason, finding applications in a wide range or areas, such as pollution monitoring, scientific data collection, sonar mapping, underwater video or mine countermeasures.

Abstract
This paper focuses on the positioning control of of a small size autonomous surface vessel (ASV) that can be used to carry a multitude of payload systems, including acoustic devices for underwater positioning and for communications with autonomous underwater vehicles. Its main motivation is the development of highly operational systems, by replacing typically moored support infrastructures with others that can dynamically position themselves. This work covers the design of feedback control laws that assure that the underactuated surface vessel Zarco can keep its position even in the presence of water currents and wind, and without special sensors to estimate such disturbances. Experimental results showing the performance of the designed control laws are also shown.

Abstract
This work addresses the implementation of the navigation, guidance and control of autonomous underwater vehicles on mobile acoustic networks. After a theoretical discussion of the algorithms required for such operation, we present results from simulation and real experiments that validate the proposed solutions.

Abstract
High frequency synthetic aperture sonar systems require demanding tolerances in motion errors and medium phase stability. This article proposes a new method that mitigates the problems associated with small wavelength related errors. By dividing the received signal bandwidths in to several smaller ones and conjugate complex multiplying them, a new signal is obtained with longer effective wavelength, thus reducing the impact of motion errors and medium phase fluctuations.