PRELIMINARY EXPERIMENT (Croatia, 22/Sept-1/Oct)
Working together for the first time at sea with a total of 6 vehicles. Undoubtedly, this was one of the first challenges of the preliminary experiment that took place from September 22nd to October 1st in Split, Croatia. The teams involved in the URready4OS project had the important task of coordinating and checking the correct functioning of the vehicles carrying out joint work, and checking that the action protocols with all the arrangements put in place was executed correctly.
That coordination and joint task aimed to check the ability that vehicles and devices have when monitoring an oil spill under the sea. In addition, the attention was also focused on possible areas for improvement in the future experiment to be performed in Cartagena.
Another basic goal during those days was the meeting and exchange of ideas to revise and enrich the preliminary version of the White Paper (text where protocol performances of the vehicles are reflected in case of oil spill).
The place to carry out the experiment was in the North of the peninsula of Marjan in Split, a place of easy access to the sea which allowed us to develop our work under the best conditions. The site was provided by the Croatian Navy.
The vehicles that participated in the experiment were: two Light AUVs (named Xplore); and two X8 UAVs from the University of Porto, the Light AUV Lupis and the USV PlaDyPos from the University of Zagreb; and an IVER2 AUV from the Technical University of Cartagena. In addition, the team from University of Cyprus was responsible for making predictions used to establish the routes to be followed by the vehicles above mentioned. For this, the MEDSLIK oil spill simulation model was used.
In total, 20 people that for 10 days took the first step for the project’s main goal which was the achievement of a fleet of vehicles operating in case of a possible oil spill, and the existence of a document that works as a guide to use underwater vehicles in these cases.
Aims of the experiment
In order to achieve the main goal, a series of milestones were established:
Probes Integration Test in each Autonomous Underwater Vehicle (AUV)
Integrating the probes in the vehicles was developed differently by each team, choosing each of them different sensor models. Therefore, one of the first goals was to verify that the integration was done correctly. For this purpose an intercalibration was performed thereof, ensuring that the measurements between the probes were homogeneous.
For this purpose, the Croatian team developed a dilution of Rhodamine WT with a concentration of 100 ppb, and a white one without dye. Subsequently, it was shown that all the values obtained by each of the vehicles were close to 100 ppb, so it was only necessary to make some adjustments to the calibration coefficients. The result was a successful intercalibraton.
Communications Test between Vehicles and to the Ground/Ship Station.
Synchronization was the next step. Verifying that the communication between the UAVs and the AUVs (LAUV-xplore1, LAUV-Lupis and IVER2-EM190) was produced correctly became another goal of the experiment. Making that the data from marine vehicles in the process of their appearance in surface reached the land base was possible thanks to the coordination between them and the aerial equipment. The mission of the latter was not only to transfer that information but also from its privileged position, to make panoramic photos of the Rhodamine WT plume. In all cases, the goals were achieved.
Underwater Communications Test between USV, AUVs.
From 5 to 10 seconds was the time interval that the vehicles took to send the information to the base station while being submerged. Those in charge were two vehicles performing these functions differently: the Lupis did it through a signal sent to the vehicle in the surface, using an acoustic modem that was in charge of sending that signal to an aerial equipment or directly to the base camp via WI-FI. The Xplore performed this task differently. Its signal, also acoustic, was sent directly to a receiver located at the ground station.
Positioning Test of all Vehicles in Command and Control Console (NEPTUS).
Knowing the position of each vehicle at any time is crucial for the project’s success. It is a basic point for the actions to develop in a coordinated and accurate manner, and for the final goal to succeed. To achieve this goal, a program of Command and Control called NEPTUS, which was developed in the LSTS (Underwater Systems and Technology Laboratory, University of Porto), were used. This software allowed verifying and checking the location of all the equipment simultaneously and in real time.
Integration of Data Test in the Command and Control Console (NEPTUS).
The capabilities of NEPTUS are not just limited to showing the simultaneous location of all vehicles, regardless of their position, but to also to enable data collection and display them collectively. Thus, in a next mission, thanks to the drawing where that collected information is shown, vehicles can approach the source of the stain to obtain more accurate data. The optimization is evident, accelerating and improving performance times.
Test of Protocols for Communication.
The communication in any experiment is crucial, especially when it comes to vehicles that have to be perfectly coordinated with each other for the success of the mission. Before this test, each vehicle was developing and using its own protocol, but for the success of the mission it was vital to set up a common one for all of them. During those days we worked on it. The best example of achieving this goal was the integration of a vehicle (IVER2), developed by a unrelated commercial enterprise to the NEPTUS system.
Test of Protocols for Operations.
Besides the communication based on facts, in concrete actions, it is necessary to capture those ideas in written form. The White Paper gathers each step of the interventions to be performed, and specifically, in this experiment developed in Split, in this case the formal functioning of the vehicles is improved, gathered in the so-called ConOp.
Operational Test with Several Vehicles Deployed at a Time.
Making vehicles to, accurately, be directed to and to fulfill a mission at a time and a given place is relatively simple. But the real challenge was to solve it with all the teams working at the same time. For this, the detail of the operation must be very precise, and this was done in this experiment, reaching the elusive goal of operating with three AUVs responsible for measuring the Rhodamine WT under the water, a UAV responsible for transmitting data to the ground, and a USV responsible for collecting the data under the water.
After achieving each of the previous steps successfully, the experiment had to go a step further: checking that the entire set of actions mentioned previously were operating in a real situation.
To perform this last mission, and through a boat donated by the Croatian Navy, the whole team started working, in the first place, to make that supposed oil spill, using, for obvious reasons, Rhodamine WT. Thus, and although in the first moments the volume that would simulate a real spill was not achieved, and complicating the detection for the vehicles, later, changing some variables, the necessary plume to make the actions in a real way was achieved.
The next stage was to gather information about which of the different sampling strategies of the vehicles was most appropriate in these emergencies.
After a busy day, the achievement of the goals was a reality. Therefore, firstly, it was possible to detect the plume under the water; secondly, to receive data in real time while the vehicles were submerged; thirdly, to synchronize all the vehicles with the onboard computer; and finally, to draw the data in NEPTUS, and to know the position of each of the teams at any moment.