Speed - Speed and turbulence measurements for AUVs

Access/Technology provider: Norwegian University of Science and Technology – NTNU, NTNU-SF30K and NTNU-SMALL_AUV

End User: Tallinn University of Technology (TalTech) Estonia

Dates: November 2020 – November 2021

Goals: The objective of this proposal is to field test a novel sensor, a differential pressure based speedometer (DPSS) for measuring robots speed and for measuring turbulence.

The turbulence patterns in oceans might provide additional information for robot navigation or oceanographic information for investigating physical processes at mixing zones, river plumes, frontal systems and internal waves. The project also aimed on verifying the sensor performance with respect to ground truth from that would decouple water motion (current speed and vehicles’ motion with respect to water) from the ground velocity. Due to COVID restrictions and travel restrictions TNA experiments was executed as a remote access. DPSS sensors were shipped to access provider NTNU, and experiments started from the beginning of 2021. Project consisting of two different TNAs: ROV SF 30K and small AUV-LAUV. For small AUV TNA, DPSS sensor was integrated on LAUV vehicle and trials were performed at the mouth of Nidelva and Gaula river. LAUV flew through the mixing zone of fresh and salty water on low depths of 0.5 meters to 2 meters. Trials were performed at multiple occasions during the 2021. Trials with ROV were performed at different location in Trondheim fjord from the R/V Gunnerus. Two sensors were installed on ROV SF30K, symmetrically separated and mounted that there is unimpeded flow over the sensor head. Sensors have logged data autonomously. During the trials ROV was operated by the ROV pilot at depths to approx. 100 meters in 10-20 meters steps.