SPECTRAL CHARACTERIZATION OF UNDERWATER ACOUSTIC EFFECTS

    INFANTE - DEVELOPMENT OF VEHICLES AND ADVANCED SYSTEMS FOR THE EXECUTION OF UNDERWATER INSPECTION TASKS

    ASIMOV - ADVANCED SYSTEM INTEGRATION FOR MANAGING THE COODINATED OPERATION OF ROBOTIC OCEAN VEHICLES

    BLIND ARRAY PROCESSING IN MOBILE COMMUNICATIONS (concluded)

    AUTONOMOUS ROBOTIC METHODOLOGIES FOR MULTIDISCIPLINARY APPLICATIONS
 

SPECTRAL CHARACTERIZATION OF UNDERWATER ACOUSTIC EFFECTS

Leader    Prof. Victor Barroso

Project description
The acoustic effects that are observable with submersed sensors are of extremely difficult characterization. Great part of the difficulties are due to the propagation physics of the underwater acoustic channel, namely reverberation, scattering and multipath. On the other hand, the noise sources are typically non stationary, constraining therefore the techniques that can be used. Here, Time-Frequency signal analysis techniques are considered to deal with the spectral time variant content of the signals of interest. It is expected to obtain accurate signal characterizations so as to achieve improved classification results.

Research Areas
Time-Frequency Signal Analysis

Laboratories
Signal Processing (SPLab)

External Partners
Escola Naval

Initiated: 1999
Expected conclusion: November 2001
Classification: Programa Ambiente e Defesa, Ministérioda Defesa Nacional - Fundação das Universidades Portuguesas

INFANTE - DEVELOPMENT OF VEHICLES AND ADVANCED SYSTEMS FOR THE EXECUTION OF UNDERWATER INSPECTION TASKS 

Leader    Prof. João Sentieiro (IST/ISR)
SPLab     Prof. Victor Barroso

Project description
The objectives of this project are the design and the construction of an autonomous underwater vehicle (AUV), and the development and integration of advanced systems for navigation, guidance and control, acoustic data communications and mission management. These systems will be tested in the lab. Once they are installed in the vehicle, they will be also tested in pool and sea trials.

Research Areas
Control Theory, Computer Vision, Signal Processing, Underwater Acoustics

Laboratories
Dynamical Systems and Ocean Robotics Lab (DSORL), Signal Processing (SPLab), Computer and Robot Vision.

External Partners
CINTAL-Univ. do Algarve (P), RINAVE (P), Instituto Hidrográfico (P)

Initiated: 1997
Expected conclusion: December 2000
Classification: PRAXIS XXI 3/3.1/TPAR/2042/95

ASIMOV - ADVANCED SYSTEM INTEGRATION FOR MANAGING THE COODINATED OPERATION OF ROBOTIC OCEAN VEHICLES

Leader    Prof. António Pascoal (IST/ISR)
SPLab     Prof. Victor Barroso

Project Description
Three major stumbling blocks have so far prevented demonstrating the potential applications of Autonomous Underwater Vehicle (AUVs) to demanding industrial and scientific missions. Namely, i) the lack of reliable navigation systems, ii) the impossibility of transmitting data at high rates between the AUV and a support ship at slant range, and iii) the unavailability of advanced mission control systems that can endow end-users with the ability to plan, program, and run  scientific / industrial missions at sea, while having access to ocean data in almost real-time so as to re-direct the AUV mission if required.

As a contribution toward solving some of the abovementioned problems, this project puts forward the key concept of an Autonomous Surface Vehicle (ASV) that will operate in close cooperation with an AUV, as a mobile relay for fast communications. In the scenarios considered, the ASV will be equipped with a differential GPS receiver, an ultra short baseline unit (USBL), a radio link, and a high data rate communication link with the AUV that will be optimized for the vertical channel. Thus, by properly maneuvering the ASV to always remain in the vicinity of a vertical line with the AUV, a fast communication link can be established to transmit navigational data from the DGPS and USBL to the AUV, and ocean data from the AUV to the ASV, and subsequently to an end-user located on board a support ship or on shore. Fast and reliable communications, as well as precise navigation, will thus be achieved by resorting to well established technologies.

The main thrust of the project is the enhancement and integration of proven technological systems to achieve coordinated operation of an AUV and ASV, while ensuring the integrity of the two platforms. To give the work greater focus, the final goal of the research and development effort is to perform a mission at sea - near the Azores islands - down to depths of 100 m, to determine the extent of shallow water hydrothermalism and to determine the patterns of community diversity at the vents in the area. In the envisioned scenario, the AUV will be asked to maneuver close to the seabed and to detect the occurrence of bubble emissions from discharging vents. The detection of those phenomena will in turn trigger the acquisition and transmission - to a support unit -  of time/space stamped sonar and video images through the vertical acoustic channel, via the ASV.

Obstacle avoidance and bubble detection will rely heavily on the development of a space-stabilized sonar head with vertical and horizontal transducer elements, and the associated signal processing algorithms. Programming, executing, and modifying on-line the plans for joint ASV/AUV operation will be made possible by developing dedicated systems for joint mission and vehicle control, as well as appropriate Human-Machine interfaces. Special emphasis will be placed on demonstrating all the steps that are necessary to acquire, process, manage, and disseminate data on  hydrothermal activity  to a wide audience of scientists, over the Internet.

Research Areas
Navigation, Guidance, and Control, Acoustic Communications, Obstacle Detection and Avoidance, Sonar Systems, Mission Control of Autonomous Vehicles, Ocean Robotics.

Laboratories
Dynamical Systems and Ocean Robotics Lab (DSORL), Signal Processing (SPLab)

External partners
ORCA Instrumentation (FR), GESMA - Laboratory of the French Navy (FR), ENSIETA - School of the French Navy (FR), System Technologies (UK), University of the Azores (PT).

Initiated:  January 1998
Conclusion : 2000
Classification: Contract No: MAS3-CT97-0092  (Commission of the European Communities), Programme MAST-III (Marine Science and Technology) of the EC, 1998-2000).

Leader    Prof. Victor Barroso (IST/ISR)

Project description
This project addresses the problem of the blind separation of digital sources which are transmitting simultaneously in time using the same frequency channel and, eventually, the same code. Using an array receiver, the sources can be discriminated by their spatial signatures. The objectives of the project are to develop closed form  blind receivers.

Research Areas
Statistical Array and Signal Processing, Signal processing for Wireless Communications

Laboratories
Signal Processing

External Partners
Dept. of Electrical and Computer Engineering, Carnegie Mellon University (USA)

Initiated: 1997
Conclusion: September 1999
Classification: NATO SA.5-2-05(CRG.971184)1202/97/JARC-501

Leader    Prof. João Sentieiro (ISR)
SPLab     Prof. Victor Barroso

Project description
The objectives of this project are to study, develop and test methodologies for both sensoring perception and guidance of autonomous vehicles operating in dynamic, structured and partially structured environments known up to some uncertainty level. This project considers all the different functional modules necessary to define the locomotion dynamics of an autonomous robot: positioning, obstacle detection and recognition, control, path planning, communications and mission management.

Research Areas
Systems Theory, Control Theory, Computer Vision, Signal Processing, Artificial Intelligence, Estimation and Detection Theory, Pattern Recognition

Laboratories
Artificial Intelligence and Manufacturing Systems, Intelligent Control, Mobile Robotics, Underwater Robotics, Signal Processing, Computer and Robot Vision.

External Partners
ISR Porto (P), ISR Coimbra (P), Faculdade de Medicicina da Univ. de Coimbra (P), INDEP (P), IGM (P).

Initiated: 1995
Expected conclusion:  March 2000
Classification: PRAXIS XXI 3/3.1/TPR/23/94