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PETROMAKS2-Stort program petroleum

iDROP Oceanid™ Navigator (iDRONA)

Alternative title: iDROP Oceanid™ Navigator (iDRONA)

Awarded: NOK 3.5 mill.

The main element of the project is the propulsion of the Oceanid vehicle, purely based on gravity with the ability to autonomously glide laterally in the water column to a predefined position on the seabed, where it can carry out scientific measurement tasks. When the sensor data acquisition has been completed and sensor data stored locally, the unit will carry out an environmentally friendly re-ballasting that creates positive buoyancy, and thus propulsion, allowing the vessel to glide controllably back to a defined point on the surface where it is salvaged. When the unit moves in the vertical water column, descending or ascending, the sensor platform internally as well as the onboard navigation solution enables and improves the quality of vehicle control in real time. Or collect and post-processed sensor data in parallel with traversing the water column, for future utilization in connection with re-installation or if several vehicles are to be installed sequentially. Measurement and logging of basic sensor data such as pressure, temperature and sound speed in different water layers passed can be used to improve acoustic communication, and then improve underwater positioning through acoustic distance measurement and trilateration. The swarm of vehicles combines a high-quality inertial meter, pressure and compass data, as well as the digital twin model of the unit, to estimate relative position along the planned glide path. This project aimed to measure the difference in this estimated dataset with the positions calculated based on trilateration and acoustic distance measurements – ToF (time-of-flight). By collecting the dataset from the motion of a vehicle and consolidating data from multiple vehicles deployed in several celestial directions, and then post-processing the data volume, one is able to establish an accurate current profile in near real time. This high-resolution current 3D-profile, based solely on existing hardware in the individual vehicle and collectively processed on board the support vessel, can subsequently be utilized to further improve the quality of vehicle control of new installations, for example by improved positioning accuracy and more efficient lateral movement away from support vessels. In the project, scaled trials have been carried out on board research vessels as well as a separate survey boat, where acoustic measurements, sound speed and current measurements have been obtained for further development of processing algorithms, typ. position estimation and establishing a current profile.

Dagsaktualiteten til løsningen og mulig bruk av prosjektets resultater er dessverre større enn teamets ambisjoner på søknadstidspunktet, hvor nasjonal- og regional sikring av energiforsyning og maritime transportruter over, og under vann, er flyttet høyere opp på prioriteringslisten. Samtidig er grønn omstilling og fremtidsrettede løsninger for offshore næringen i fokus. Målsetningen om å videreforedle konseptet om å la en full-autonom sensor-drone installere seg selv kun basert på gravitasjon, og re-ballastering, har primært vært fokuser på konseptuell akustisk måling av avstand under vann. Det er sammenstillingen av disse måledata som har muliggjort utviklingen- og simulering av en ny kontrollalgoritme som hensyntar endringer i vannmassene og -vannsøylen man operere. Nye operasjonelle løsninger og kommunikasjonsgeometrier er etablert som et resultat av effektiv synliggjøring av energiforbruk knyttet til bruk av hydroakustisk avstandsmåling og -kommunikasjon for trilatereing, bl.a. gjennom utstrakt simulering av lydbølger. Prosjektet har også lykkes med å ta frem et nettbasert oppslagsverk som innhenter- og konsoliderer eksisterende data fra tilgjengelige målestasjoner, og tilgjengeliggjøre en 3-dimensjonal-strømprofil av vannvolumet i det aktuelle operasjonsområdet som kan benyttes for å optimalisere kvaliteten- og glidekapasiteten til selskapets farkost.

Environmental monitoring is also challenging in terms of ideally covering larger area of exploration, and longer-term measurements, compared to a more condensed production focus in an offshore license, i.e. requesting more efficient deployment of large survey spreads with a coarse sensor density. This also requires means of effective underwater communication and control, since an adoption of vessel-of-opportunity is foreseen and hardwiring between sensors physically impractical. The project proposed addresses all three challenges described above – cost efficient deployment and operation, flexibility and scalability. Complementary to a recently completed R&D-initiative (Oceanid™), funded by the European Commission (through the Horizon 2020 program), it is proposed to further investigate the concept of free-drop nodes. Or drones that “transport” a generic sensor payload laterally away from the surface drop-point, accurately and repeatedly to a predefined location on the seafloor, and upon completing the survey, return safely to the surface. The drones are purely propelled by gravity shift and a patented and environmental neutral salt-slurry ballast. Our initiative is targeting a variety of applications, e.g. installation inshore or large seismic surveys offshore. The challenge is the underwater communication and navigation, and the development of tools supporting a safe control of all autonomous activity. Based on the proposal - an efficient and accurate positioning capacity with high update-rate, the digital twin, a viritual representation of the autonomous drop-node, will allow a post-process comparison. One instance could be dedicated to the ocean current influencing the actual trajectory path, and the subtraction between the real- and simulated dataset post-processed to establish a high-density current profile. No additional sensor hardware is required, and the results can immediately be re-used for new deployments to further improve operational efficiency.

Funding scheme:

PETROMAKS2-Stort program petroleum