João Sousa

University of Porto | UP · Departamento de História e de Estudos Políticos e Internacionais

The development of increasingly autonomous underwater vehicles has long been a research focus in underwater robotics. Recent advances in deep learning have shown promising results, offering the potential for fully autonomous behavior in underwater vehicles. However, its implementation requires improvements to the current vehicles. This paper propos...

The study of dynamic features of the ocean, in which complex physical, chemical, and biological interactions evolve on multiple time scales, poses significant sampling challenges because the required spatial and temporal resolutions are not possible by ship or satellite studies alone. Satellite remote sensing captures only surface effects while exp...

The rapid development of autonomous systems and Information and Communications Technologies (ICT) create new opportunities for maritime activities. Existing autonomous systems are becoming more powerful and utilise the capabilities of several types of devices such as Autonomous Underwater Vehicles (AUVs), Unmanned Surface Vehicles (USVs) – sometime...

Localization is an important required task for enabling vehicle autonomy for underwater vehicles. Localization entails the determination of position of the center of mass and orientation of a vehicle from the available measurements. In this paper, we focus on localization by using One-Way Travel Time (OWTT) measurements available to a vehicle from...

Position estimation is one of the important tasks to achieve vehicle autonomy. This article addresses the problem of estimating the position of the center of mass of a vehicle from range measurements that are available to the vehicle via communication of its on-board receiver to multiple beacons. The model proposed in this article assumes that the...

Our research concerns the mixed-initiative coordination of air and underwater vehicles interacting over inter-operated radio and underwater communication networks for novel oceanographic field studies. In such an environment, operating multiple vehicles to observe dynamic oceanographic events such as fronts, plumes, blooms and cetaceans has require...

Our research concerns the mixed-initiative coordination of air and underwater vehicles interacting over inter-operated radio and underwater communication networks for novel oceanographic field studies. In such an environment, operating multiple vehicles to observe dynamic oceanographic events such as fronts, plumes, blooms and cetaceans has require...

We often take Web connectivity for granted. This can be the case in our houses where we rely on more and more devices that connect to the Internet and exchange information with remote servers or other nearby devices around using cheap Wi-Fi radios. However, the world remains for the most part disconnected. There are still uncountable remote areas w...

This paper deals with two aspects, namely a historical analysis of the use of unmanned vehicles (UAVs ROVs, AUVs) in maritime spill incidents and a detailed description of a multi-agency oil and HNS incident response exercise involving the integration and analysis of unmanned vehicles environmental sensing equipment. The exercise was a first in ter...

Exercise Cathach was a large training exercise which utilised and evaluated the use of Unmanned Underwater Vehicles (UUV's) and sensors in a maritime spill Incident involving oil and harmful and noxious substances (HNS). The exercise was a first in terms of the level of robotic systems deployed to assist in survey, surveillance and inspection roles...

Supervision and control of Autonomous underwater vehicles (AUVs) has traditionally been focused on an operator determining a priori the sequence of waypoints of a single vehicle for a mission. As AUVs become more ubiquitous as a scientific tool, we envision the need for controlling multiple vehicles which would impose less cognitive burden on the o...

This paper describes a command and control infrastructure that provides mixed-initiative user interfaces for the coordination and control of networked vehicle systems composed by heterogeneous robots, satellite trackers, manned ships and communication gateways. The presented infrastructure was tested in a field experiment for tracking and sampling...

Obtaining synoptic observations of dynamic ocean phenomena such as fronts, eddies, oxygen minimum zones and blooms has been challenging primarily due to the large spatial scales involved. Traditional methods of observation with manned ships are expensive and unless the vessel can survey at high-speed, is unrealistic. Autonomous underwater vehicles...

Field operations in remote locations or within hazardous scenarios benefit greatly from the ability to deploy general purpose networks that can be accessed not only by operation vehicles but also human participants. The existence of these networks allows the transmission of data vital to operation success that otherwise might not have the means to...

This paper describes scientific and engineering efforts towards remote sensing, tagging and continuous tracking of sunfish specimens (Mola mola, world largest bony fish) in the open sea. This ongoing experiment is done in the context of a collaboration between MBARI and Porto University and bridges biology, fisheries research, autonomy and control...

With the prevailing increase of complex operational scenarios, involving multiple unmanned aerial vehicles (UAV), the concerns with the natural increase of operator workload and reduction of situational awareness have become paramount in order to safeguard operational security and objective completion. These challenges can be tackled through altera...

This paper describes the open-source software toolchain developed by the Underwater Systems and Technology Laboratory (LSTS) for supporting networked heterogeneous air and ocean vehicle systems. The toolchain supports the deployment of air and ocean vehicles interacting over limited acoustic and wireless networks combined with disruption-tolerant n...

This paper presents the LAUV (Light Autonomous Underwater Vehicle), with special emphasis on the most recent developments and discusses how the LAUV enables networked operations. The LAUV is a lightweight, one-man-portable vehicle specially designed to be a highly operational and effective surveying tool for oceanographic, hydrographic, security an...

This article concerns an approach for cooperative plume tracing in an underwater environment characterized by very strict communication constraints such as delays, low reliability and limited bandwidth, as well as by the absence of natural features which would help localization and navigation. Localization is of utmost importance for plume tracing...

In the video we present results obtained from experiments we ran with multiple unmanned vehicles. The vehicles used in the experiments were made in the LSTS, which is introduced in the beginning of the video. A formation control problem using an Autonomous Surface Vehicle and an Autonomous Underwater Vehicle is presented first, then followed by a m...

We describe the process of improving the onboard autonomy of LAUV-Seacon AUVs with an in-situ planning agent. Deliberative planning is achieved by extending the existing control architecture with T-REX and a domain model description which is specific to the Seacon AUVs and typical mission scenarios. We discuss the required architectural changes as...

We present a formation flight control strategy featuring a collision avoidance scheme. The control algorithm is based on a Sliding Mode controller. The controller sliding surfaces account for aircraft maneuvering limitations, restricting the required velocities to a feasible set. Further, the relative position between vehicles affects the sliding s...

The problem of leader-follower control of two under- water vehicles communicating via acoustic modems is formulated and solved in the framework of sliding mode control techniques. In this problem the path of the leader is not known in advance by the follower. The problem is formulated and solved using non- linear control techniques and non-linear m...

SAFE-PORT is a recently started project addressing the complex issue of determining the best configurations of resources for harbour and port surveillance and protection. More specifically, the main goal is to find, for any given scenario, an adequate set of configuration solutions - i.e., number and type of sensors and equipments, their locations...

The problem of driving a set of vehicles (agents) to a desired target configuration under event-based communication and measurement constraints is analyzed. We start by studying the single agent problem, where we propose a waypoint based solution, along with two alternative control strategies. After deriving their properties and proving some releva...

A team of unmanned aerial vehicles (UAVs) with limited communication ranges, communication delays and limited resources are deployed to search and prosecute static and maneuvering targets in a region. When a UAV detects a target, depending on the target resource requirement, it has to form a coalition for prosecution. Forming a feasible coalition o...

This paper presents an integrated navigation system for autonomous underwater vehicles which is based on a Strapdown inertial navigation system (SDINS) accompanying Doppler velocity log (DVL), pressure sensor and magnetometer. The paper focuses on the performance analysis of the bias of inertial sensors and the error of position using different lev...

The problem of driving a formation from an initial to a target configuration while under the effect of external disturbances is studied. Additional restrictions on agent sensing as well as inter-agent communication must be satisfied. We present a leader-follower solution that relies on a simple uncertainty model to trigger surfacing events. These e...

In a search and prosecute mission, multiple heterogeneous unmanned aerial vehicles UAVs that carry different resources need to perform the classify, prosecute and battle damage assessment (BDA) tasks on targets sequentially. Depending on the target resource requirement, it may be necessary to deploy a coalition of UAVs to perform the action. In thi...

In this paper, we develop a coordination mechanism for multiple autonomous underwater vehicles (AUVs) and a single unmanned aerial vehicle (UAV) cooperatively performing a ocean exploration mission. The UAV and the AUVs have limited sensor and communication constraints. The AUVs are deployed in the ocean and surface when their mission leg is comple...

In the last decade we have witnessed an unprecedented development of Unmanned Air Vehicles (UAVs) for missions with high societal impact. Future generations of UAV systems will reflect the major current trends: increased levels of autonomy, lower cost, longer endurance, and networking capabilities. Networking is one of the major trends for unmanned...

A viability algorithm is developed to compute the constrained minimum time function for general dynamical systems. The algorithm is instantiated for a specific dynamics(Dubin’s vehicle forced by a flow field) in order to numerically solve the minimum time problem. With the specific dynamics considered, the framework of hybrid systems enables us to solv...

There are many applications that map the reality onto virtual environments, through the projection of real images. One of the most popular examples is Google Earth which is applied to geography and other examples include Nasa World Wind, and 3D scanners applications. Implicit in these methods is a perfect alignment in the camera positioning between...

This paper presents the MonSense application that is currently being used at our laboratory to deploy, monitor and control Wireless Sensor Networks (WSN). MonSense can connect to various sensor networks (each one composed by multiple sensor nodes) by interfacing with one or more gateways that forward information received by attached networks. The s...

Abstract The Mobile Offshore Base (MOB) is a large, self-propelled, floating, pre-positioned ocean structure formed of three to five modules and reaching up to 1,500 meters in length. It must accommodate the landing and take-off of C -17 conventional aircraft, host 3000 troops, carry 10 million gallons of fuel and provide 3 million square feet of i...