The Operational Area is within the “Parco Nazionale delle Cinque Terre” – 0.3 nm around C80 point (N 44 04.550, E 09 40.675), inside CMRE berthing area and outside the CMRE waterfront.
13th - 16th Oct: OceanRINGS System Core was integrated with CMRE software in Virtual Environment (Dula Nad, Gabriele Ferri & Edin Omerdic). Dynamics of Virtual ROV LATIS and virtual ship LEONARDO were simulated in different sea states and time-varying ocean currents. Sonar simulation and aROV GOLDRAKE dynamics was simulated with CMRE software. Data exchange link was realized through software architecture “Mission Oriented Operating Suite - Interval Programming “(MOOS - IvP), developed by the Mobile Robotics Research Group at Oxford University, the Computer Science and Artificial Intelligence Lab and Dept. of Mechanical Eng. at MIT, and the Naval Undersea Warfare Centre in Newport Rhode Island (NUWCNPT).
MOOS Interface integrated in ROV LATIS Pilot Interface application
Toggle button “MOOS Enabled” serves as a software switch to select who has a direct control of ROV LATIS. An enabled state confirms that the Command Centre has direct control of the ROV. Depending on a state of the mission, Command Centre sends commands to ROV LATIS to change/keep depth, keep distance from aROV/Target etc. Also, when disabled, LATIS ROV pilot regains direct control. In normal situation ROV pilot will take control after the mission is completed. However, ROV pilot continuously monitors mission progress and can interrupt the mission execution and take control at any moment if something goes wrong.
16th - 17th Oct: Virtual Reality model of ship LEONARDO was converted from 3D Studio format to VRML format (Dula Nad) and integrated within OceanRINGS (Edin Omerdic). The VRML format was used later for 3D real-time visualisation of mission progress.
14th - 17th Oct: Integration of the LATIS control cabin, winch and ROV took some time as CMRE inspections and checking of certification called for additional welding and inspection/certification before clearing ROV Latis systems for secure use aboard CRV Leonardo’s deck. Once the equipment was on board, integration with the ship (electronics, communications) began and was completed a day later. Following this, ROV LATIS was deployed in dock to a depth of 2 metres when some short circuit faults presented. The ROV was recovered for test and repair. Testing took some considerable time to isolate the root cause of the faults and found a faulty thruster as well as a flooded thruster bottle bulkhead connector cable assembly (possibly damaged during transport). The faulty thruster was removed from the ROV for all subsequent tests and the CMRE workshops improvised a thruster bulkhead connector replacement. The Sea borne testing began following the repairs and subsequent integration.
Over a number of days CRV Leonardo departs from CMRE berthing area, transits to the experimental site, performs standard operations and attends deployed ROV systems, and returns to the CMRE berthing area. ROV LATIS and aROV GOLDRAKE were deployed and performed operations in the designated area. The CMRE rubber boat support was available at all times for assisting the operations and warning the nearby vessels.
Operations began on Oct 18 with the target deployment. Due to the hardware problems described above in the previous section, several first days were lost. On Oct 22 the target was deployed in the main operational area in Cinque Terre. The following days were used for autonomous mine neutralisation missions using the ROV LATIS and aROV GOLDRAKE systems. Various ROV LATIS behaviours were performed and sonar data collected. Post-processing and data quality checks took place in the Leonardo lab.
Shown below are the results obtained during one of the experimental missions.
Two state-of-the-art forward looking sonar (FLS) imaging systems were mounted onto LATIS over the course of the experimental operations. These systems include the P900 from Teledyne Blueview and the 7128 SeaBat from Reson.
The P900, operating at 900 KHz, constructs 256 beams (synthetic) into a 90 degree swath fan beam and is capable of producing an image map with range resolution of 25.4mm. The P900 comes in a small lightweight package and is relatively low cost. The SeaBat 7128, operating at 400 KHz, constructs 256 beams, 128 degree swath, is capable of a finer range resolution of approximately 6mm and the imagery is clearer out to longer ranges up to 100m. On the other hand the 7128 comes at a higher cost and is significantly larger in size.
Both systems were mounted on the front of ROV Latis and used to collect datasets during ROV missions enabling simultaneous acquisition. This allowed for high resolution imagery of the surrounding environment including (aROV and Mine / cylinder target) up to 50m distant for P900 and greater ranges up to 100m distant for the Reson 7128.
Detection of submerged objects such as debris (various), aROV GOLDRAKE, MCM targets (cylinders) and harbour installations (walls, anchors etc) became easily viable. In addition, surface objects such as ship and Rhib hulls as well as propeller wake (bubbles) were also identifiable in these datasets.
The first image is taken in 9 MSW while the second one is taken in 80MSW. Distance scales are as follows (max point) – 7128 is 50m in image1 and 75m in image2, P900 is 40m in image1.
The third image above shows the target at 68 metres distant from LATIS and the aROV at 30 metres distant. The shape of both objects is clearly identifiable from the returned data, the signal strength of the sonar returns gives an indication of composition and the shadow from the return gives an indication of height from the seabed.
This shows the capability of the Reson 7128 forward looking sonar imaging system in terms of identifying targets at significant distances from the sonar head. The data received from the Blueview sonar was not capable of identifying the target at this distance.
The image above shows the data captured during a deep water mission in a depth of 80 MSW over a rocky seabed. Two targets were deployed at this site, the cylinder target and a large 1 Tonne rock.
Again, the capability of the forward looking sonar imaging system is demonstrated. The data received shows a stronger return from the seafloor. However, shape and identification of each of the targets are easily resolved even at extended depths.