Anja Babić, Nadir Kapetanović, Igor Kvasić
The IEEE OES University of Zagreb Student Branch Chapter (UNIZG SBC) was one of the co-organisers of this year’s Breaking the Surface conference and workshop. The event took place from 27 September to 4 October in Biograd na Moru, Croatia, and despite challenging conditions and limited attendance, the conference succeeded in bringing together experts in maritime robotics and applications and maintained its annual tradition.
Breaking the Surface is known for its hands-on tutorials and lectures, exciting presentations of new equipment and networking through social events. It was a great challenge to organize such a conference in 2020, but by combining increased organisational effort, a reduced number of international and in-person guests, strong support from local experts, and virtual lectures from around the world, BtS continued to foster interaction and knowledge sharing in various marine-related areas. Significantly, six of our chapter members, Frane Rogić, Anja Babić, Ivan Lončar, Vladimir Slošić, Igor Kvasić, and Nadir Kapetanović had the opportunity to share the latest developments and results of their PhD research and discuss ideas with colleagues from various fields of engineering in specially organised sessions that enriched this year’s BtS programme.
In his presentation titled “Underwater Localisation”, Frane Rogić spoke about a method often used to locate small underwater vehicles – the use of single range measurements from a known location combined with dead reckoning to calculate real-time localisation. As he pointed out, underwater localisation and navigation still pose a major challenge in underwater robotics, especially when reliability and accuracy are required. His research focuses on finding the most meaningful location for a single static beacon, ranging from it to an autonomous vehicle. This extends to the so-called breadcrumb algorithm, which he implemented by having an AUV add to its surroundings new static beacons with uncertain positions, which then provide new range measurements that help with the localisation problem.
Anja Babić introduced her work focusing on a marine robot swarm, which was developed with the aim of autonomous long-term monitoring of environmental phenomena in the very challenging ecosystem of Venice, Italy. The swarm is made up of autonomous surface platforms named aPads and underwater robotic sensor nodes named aMussels. Anja described her work on a scenario where this system has to autonomously perform its monitoring mission and survive for a long period of time by exchanging energy, and in which the available maximum capacity of 5 aPad platforms, which are the system’s charging centers, is usually exceeded by the number of active charging requests. This in turn means careful planning and optimization of robot activities are necessary. Therefore, Anja developed a two-layered system of decision-making algorithms: a specific solution-focused set of low-level algorithms and a high-level hyper-heuristic that selects between these algorithms depending on various performance indices. Anja also presented data collected during experiments conducted in Biograd last year.
Next, Ivan Lončar presented the results of his research in a presentation titled “Acoustic Localisation Of Underwater Sensors Using Cooperative Unmanned Marine Vessels”. As he mentioned, underwater monitoring is a popular research topic, focusing on the use of low-cost underwater acoustic sensor networks (UASNs) for tasks such as oceanographic data acquisition and underwater event detection. Underwater localization plays a crucial role in the georeferencing of the collected data. Typically, localization systems for UASNs use a fixed infrastructure for supported localization. The approach proposed by Ivan uses ASVs as localization anchors to reduce costs and improve mobility. He developed a method for a localization algorithm based on time difference of arrival to plan the trajectory of a formation of ASVs. The goal of this method is to achieve the desired localization accuracy of the entire UASN.
Vladimir Slošić, our newest member, spoke about production, testing and possible use-cases of underwater acoustic beacons as one way to address the challenges of underwater communication and localization. Low cost, low power underwater acoustic beacons (or pingers, as Vladimir called them) with an acoustic range of up to several hundred meters are increasingly being produced. The concept of the pinger was discussed – Vladimir talked about how it would work, what its purpose was and what technologies it was based on. Secondly, the main production and testing challenges were mentioned. Finally, Vladimir suggested some possible applications and showed results of several proof-of-concept tests he had done in pools, lakes, and the Adriatic Sea.
Igor Kvasić introduced the audience to the topic of underwater interaction between humans and robots and the possibilities of finding a robust and reliable sonar image processing method for detection and tracking. This is not only a practical challenge, but also an outstanding safety feature. Igor gave an overview of current imaging sonar technologies as well as methods for object detection, with a focus on methods that have the potential to be used to detect a specific object, such as a human diver, and to determine their applicability in real-time operation. Igor also showed some preliminary results he has achieved training neural networks on diver datasets he collected himself.
Nadir Kapetanović emphasized the importance but also the complexity of online methods for efficient mapping of an unknown large-scale marine area using a side-scan sonar onboard an autonomous marine vehicle. Ensonifying some parts of the survey area (that contain detected interesting objects) in more detail, while covering the rest of the area less thoroughly is the idea at the core of one dynamical programming-based and three heuristics-based coverage path planning algorithms that he proposed in his research. The proposed coverage algorithms provide a coverage solution based on local information gain computed from the side-scan sonar data during the mission execution. Apart from the coverage path planning problem, Nadir addressed the problem of anomaly detection in side-scan sonar imagery by making a performance comparison of various image processing methods on simulated as well as real-world side-scan sonar imagery datasets.
All of these presentations, as well as a round-table discussion organised as part of the INNOVAMARE project and talks given by international guests and long-term BtS supporters such as António Pascoal and Fausto Ferreira, were streamed online using Microsoft Teams and are available on demand on the LABUST YouTube channel.
Our PhD student members also stepped up and gave several interesting tutorials and demonstrations outside by the marine pool and two of the bays in Biograd frequently used for our experiments. On Wednesday, September 30th, Vladimir Slošić and Kristijan Krčmar gave a 90-minute tutorial on the manufacturing process of underwater locator beacons (the previously mentioned “pingers”). This included both the perspective of mechanical engineering, including 3D modeling, 3D printing, and manufacture, as presented by Kristijan, and electrical engineering, including electronics and algorithm development, as presented by Vladimir.
That same afternoon, Nadir gave a practical tutorial in which he gave a short presentation about the Lightweight Autonomous Underwater Vehicle (LAUV) Lupis, including its hardware and software components. This tutorial described and demonstrated how LAUV Lupis is used, controlled and tracked by a USBL system and how its side-scan sonar and camera-based survey/inspection missions are planned and executed under consideration of various operational safety measures. The attendees then deployed the vehicle and started the designed mission, after which the collected side-scan and camera images were analysed, taking into account the prospects for detecting anomalies in sonar images and photogrammetric methods applied to the collected visual data.
Anja Babić, Ivan Lončar and Marko Križmančić presented the results of The Horizon 2020 Future and Emerging Technologies project subCULTron during a hands-on tutorial titled “The Basics Of A Monitoring Mission” on Thursday, October 1st. During this tutorial, a brief introduction and demonstration of aPad and aMussel robots were given, including accessing basic interfaces, communication, and programming, execution, and monitoring of an example mission.
An important mission of our SBC is not only work strictly in the fields of science and technology, but also education and dissemination. We pay special attention to working with bright young minds and always try to involve local communities. This year we had the opportunity to welcome students from a local high school in Biograd specialising in the fields of naval architecture, shipbuilding, and naval engineering. Our members, Igor Kvasić and Nadir Kapetanović, were happy to show the pupils marine robots and their latest capabilities in action. Furthermore, the students had the opportunity to manually maneuver one of the aPads as well as our newly acquired Blueye PRO ROV. They were thrilled to take part in the demonstration of the robotic equipment and more than happy to manually control the vehicles.
It’s always nice to share knowledge with younger enthusiasts, introduce them to a field of research and development most of them have never heard of, change their perspective on science in general and spark their curiosity. Hopefully, some of them will choose their career in science and work with us in the future!
Being socially responsible and complying with the latest epidemiological recommendations, we were able to hold a social event on the evening of the first day of the Breaking the Surface conference, Monday, September 28th. Although the number of participants at this year’s BtS was reduced by about five times compared to previous years and the guests were mainly local, we did not want BtS to lose its spark and one of its main priorities – networking and exchange of ideas. At this event, which we called “IEEE OES UNIZG SBC’s Equipment Showcase”, the latest activities of the student branch were presented, including a small exhibition. Participants were able to ask our members all about the equipment they work with in a more relaxed environment.
This year’s unusual edition of the Breaking the Surface conference was certainly a memorable one from an organisational perspective. It was held in the face of great uncertainty and with a significantly reduced number of participants. We have tried to bridge the gap from in-person lectures to virtual and streamed ones as seamlessly as possible. Despite the success of the event, we hope next year’s BtS will return in its well-established form and we hope to once again get to enjoy it with all our international friends and colleagues.