Navigation of ROVs and Basic Signal Processing

• Main Author: Truong, Phat Tan
• Format: Others
• Language: English
• Published: Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk 2011
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15451

A dynamic positioning (DP) system for a ROV is being developed in the Automated Underwater Robotics (AUR) laboratory at the Norwegian University of Science and Technology (NTNU). The AUR lab at NTNU has a ROV and a research vessel at disposal for development and testing of the DP system. The DP system is dependent on having a trustworthy and robust navigation system that provides navigational data in order to control the ROV efficiently. Such a system, a navigation computer running a navigation software called Navipac, is currently being provided by a company named EIVA. It is however desirable to have full control over the raw sensor signals at any given time. The exact details about how Navipac process the raw signals is essentially unknown to the user. A navigation system that will replace Navipac is therefore needed in order to achieve a fully standalone system. This will allow tighter integration with the DP system as well as allowing customizations to fit the DP control system needs. A navigation system has therefore been implemented using hardware and software solutions provided by National Instruments. The most important functionality of the implemented navigation program is the providing of the needed navigational data to the DP control system. Additional features such as logging utilities for post processing and a graphical user interface (GUI) for easy operation has also been added to the program. Full scale tests has been performed in the Trondheimsfjord with NTNUs research vessel R/V Gunnerus and ROV Minerva while using the developed navigation system. The tests were successful and the navigation system yielded decent performance. The results however also shows that the performance of the DP system was somewhat degraded compared to when using Navipac for navigation. The degradation in performance was most likely caused by a small delay in the communication between the navigation system and the DP system. Further work should include investigating the cause of this delay closer.