Artur Piotr Zolich

Unmanned aerial vehicle as communication relay for autonomous underwater vehicle — Field tests

This paper describes field experiments with an X8 Unmanned Aerial Vehicle (UAV) operating as a wireless communication relay while loitering over a REMUS 100 Autonomous Underwater Vehicle (AUV) being at the ocean surface. The paper describes the design of the communication relay payload, network configuration, optimal flight conditions and UAV antenna mounting, and experimental results. Experiments were conducted under less than ideal conditions with rain and turbulent winds leading to unfavorable roll and pitch motions of the UAV, and small waves surrounding the AUV. The results with data download from the AUV through the UAV communication relay to a ground station shows that at the tested (typical) flight conditions the distance and attitude between the AUV and UAV are not the bottlenecks in the communication network. The main bottleneck was identified as the capacity of the proprietary wireless system on the REMUS 100 AUV which was not specified as a high capacity data link, and seems to be set up by the AUV system manufacturer to provide a relatively low capacity, but very robust, wireless data link regardless of signal strength and quality.

Integrated Monitoring of Mola mola Behaviour in Space and Time.

Over the last decade, ocean sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of fine-scale (< 10 m) behaviour of sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both the movements and the contextual environment of the fish. A total of four individuals were tracked using custom-made GPS satellite tags providing geolocation estimates of fine-scale resolution. These accurate positions further informed sunfish areas of restricted search (ARS), which were directly correlated to steep thermal frontal zones. Simultaneously, and for two different occasions, an Autonomous Underwater Vehicle (AUV) video-recorded the path of the tracked fish and detected buoyant particles in the water column. Importantly, the densities of these particles were also directly correlated to steep thermal gradients. Thus, both sunfish foraging behaviour (ARS) and possibly prey densities, were found to be influenced by analogous environmental conditions. In addition, the dynamic structure of the water transited by the tracked individuals was described by a Lagrangian modelling approach. The model informed the distribution of zooplankton in the region, both horizontally and in the water column, and the resultant simulated densities positively correlated with sunfish ARS behaviour estimator (rs = 0.184, p<0.001). The model also revealed that tracked fish opportunistically displace with respect to subsurface current flow. Thus, we show how physical forcing and current structure provide a rationale for a predator’s fine-scale behaviour observed over a two weeks in May 2014.

Unmanned aerial system architecture for maritime missions. design & hardware description

The growing interest in Unmanned Aerial Systems (UAS) research, alongside with increasingly affordable hardware, creates great opportunity for research facilities to compare algorithms and simulation results with applied in-flight performance. However, developing the necessary equipment for such endeavour requires significant effort, often beyond available resources and the main research focus. As a solution, a system architecture for enabling advanced experiments is presented, allowing researchers to reduce the amount of required effort in developing a UAS. The proposed architecture is compatible with current state-of-the-art research facilities and standards, promoting an increased cooperation between experts in the field. The capabilities of the presented setup have evolved and been verified during intensive field experiments over the past two years, considering various algorithms and distinct equipment. This paper provides a detailed description of both the architecture and implementation details, such as the used hardware and software, being therefore a potential reference for the research community and for facilities planning the development of their own UAS.

Network of heterogeneous autonomous vehicles for marine research and management

In April 2016, NTNU, FFI, Kongsberg Seatex, LSTS and Maritime Robotics set up an experiment to explore their capability to combine the research vessel Gunnerus, the AUV Hugin, the UAV X8 and the USV Mariner in a network of heterogeneous unmanned vehicles. Communication, manoeuvring, onboard processing and operational complexity are essential components in such networks. To provide communication the MBR broadband radio system was implemented. To show the capabilities of the system proposed, a scenario with seabed mapping and target recognition was defined. The experiment made it apparent that these networks has the potential of significantly saving cost for data collection in marine research and management by reducing ship time. To fully unlock the potential of networks of heterogeneous unmanned vehicles, the missions of each vehicle need to be more integrated.

A communication bridge between underwater sensors and unmanned vehicles using a surface Wireless Sensor Network — Design and validation

This paper presents a conceptual design and field test validation of a network of surface nodes providing a communication bridge between underwater sensors and Unmanned Vehicles (UV). Here we describe the combined operations of custom made low-cost buoys and Unmanned Aerial Vehicles (UAV), linked together within one network. Buoys equipped with an underwater acoustic telemetry receiver and water parameter sensors were moored in a Norwegian subarctic fjord and the underwater sensor data and settings were made accessible via the buoys to a surface mesh-type Wireless Sensor Network. The paper describes the design and implementation of buoy hardware and software, as well as results and experiences acquired through field experiments with the system.

Coordinated maritime missions of unmanned vehicles — Network architecture and performance analysis

Multi-vehicle operations using various types of unmanned vehicles (UVs) can increase efficiency of marine data acquisition, reduce the crew risk and lower mission costs. These types of missions are very complex and often involve systems that are not interoperable. From an operational perspective however, some level of integration is necessary. Typically, a common network system architecture and Situation Awareness (SA) platform are required. The architecture allows operators to transfer data between vehicles and their operators, while the SA platform allows to monitor mission progress and react to changes. This paper presents a network system architecture used during an experiment realized in Spring 2016 in Norway. 8 departments from 5 institutions worked together to combine operation of 4 UVs (aerial, surface, underwater), a support vessel and on-shore team. The description is followed by a backbone network performance analysis. Several cases are presented, with focus on a transmission between manned vessel and Unmanned Surface Vehicle (USV), including direct connection, and data-relay mechanism via Unmanned Aerial Vehicle (UAV).

Unmanned Aerial Vehicles as Data Mules: An Experimental Assessment

Communication in remote locations, specially in high-latitude regions, such as the Arctic, is challenged by the lack of infrastructures and by the limited availability of resources. However, these regions have high scientific importance and require efficient ways of transferring research data from different missions and deployed equipment. For this purpose, unmanned aerial vehicles (UAVs) can be used as data mules, capable of flying over large distances and retrieving data from remote locations. Despite being a well-known concept, its performance has not been thoroughly evaluated in realistic settings. In this paper, such a solution is evaluated through a field-experiment, exploiting the obtained results to define and implement an emulator for intermittent links. This emulator was designed as a mission planning tool, where we further analyze the impact of different flight trajectories when retrieving data. Additionally, we study the overall performance of 4 well-known file-transferring protocols suitable for a UAV being used as a data mule. Our analysis shows that trajectories at higher altitudes, despite increasing distance between nodes, improves communication performance. Moreover, the obtained results demonstrate that DTN2, using the bundle protocol, outperforms FTP, Rsync, and SCP, and that all these protocols are affected by the size of the files being transferred. These results suggest that, in order for the scientific community to practically use UAVs as data mules, further studies are required, namely on how different UAV trajectories can be combined with efficient file-transferring network protocols and well organized data structures.

Feed spreaders in sea cage aquaculture – Motion characterization and measurement of spatial pellet distribution using an unmanned aerial vehicle

Abstract Pneumatic rotary feed spreaders represent essential equipment in the feeding system of present day industrial-scale sea cage aquaculture. This study presents experimentally obtained attitude measurements and corresponding surface distribution patterns of pellets in order to characterize the dynamic behavior and performance of such spreaders. Spreader attitude and direction were measured by employing an attitude and heading reference system along with a rotary encoder. In addition, an unmanned aerial vehicle (UAV) was used to record pellet surface impacts from the air, and the position and direction of the spreader was obtained by applying computer vision methods to the recorded video. The proposed UAV method was fast to deploy, requires minimal equipment installation and presents a viable alternative to the approach of collecting pellets manually using Styrofoam boxes as reported in earlier studies. The findings from this study may be used as a base for further development and refinement with respect to using an UAV to observe the performance and spatial pellet distribution from various feed spreaders used in aquaculture. Such a tool may be valuable for farmers and equipment producers which may easily evaluate the performance of various spreader designs. In addition, the results serve as valuable input for parametrization and validation of mathematical feed spreader models.

Increased occurrence of the jellyfish Periphylla periphylla in the European high Arctic

The jellyfish Periphylla periphylla, which can have strong ecological impacts on its environment, is ubiquitous in the Norwegian Sea and its range was predicted to extend northwards. The occurrence of P. periphylla in the northern Barents Sea increased since 2014 and, for the first time, several individuals were collected within a high Arctic fjord (> 78°N) in western Spitsbergen in January 2017. The low solar irradiance prevailing during the polar night and an increased inflow of relatively warm Atlantic water in the European Arctic since the last decade likely provide suitable conditions for the medusa to colonize Svalbard’s fjords during the winter months. However, light avoidance constrains the photophobic P. periphylla to deeper offshore areas during the midnight sun period. The current occurrence of P. periphylla in high Arctic fjords during the polar night will have a limited impact on marine ecosystems in the short term, but long-term effects are more uncertain if its abundance continues to increase.

Ultra-wide band Real time Location Systems: Practical implementation and UAV performance evaluation

Several different methods can be used to determine the 3-dimensional position of an object. A common solution is use of Global Navigation Satellite System (GNSS). However, for some operation the specific characteristics of GNSS can be challenging, e.g. time-to-fix on GPS RTK or unavailability of GNSS signals. When considering operations within limited range (a few hundreds of meters) another solution based on Ultra-wideband Real Time Location Systems (UWB RTLS). In this paper authors have tested a set-up of a tag and five anchors in order to determine if such solution can be used in local operations of Unmanned Aerial Vehicles (e.g. landing). Experimental data are analyzed and compared against GPS RTK measurements.