In the interest of enhancing the capabilities of autonomous underwater vehicles US Naval Operations, controlling vehicle position to follow depth contours presents exciting potential for navigation. Use of a contour tracking control algorithm in lieu of preprogrammed waypoint navigation offers distinct advantages within new challenges. The difficult nature of this problem lies in the non-trivial connection between the necessary corrective action and the feedback error used in traditional control methods. Stated simply, modern vehicle control algorithms separate horizontal and vertical plane navigation. The autonomous vehicle senses heading error and applies rudder to steer the vehicle to a desired heading. Simultaneously, the vehicle might sense altitude and apply stern plane angles to maintain a safe height above ground. This thesis research examines the new problem of sensing depth and altitude in the vertical plane while steering the vehicle horizontally to find a specified bathymetry contour. While more remains to understand, this research proves the existence of a solution and suggests similar approaches may facilitate tying vehicle navigation to other indirect sensors. This thesis presents two contour tracking control algorithms and examines the performance of each by simulating the response of the REMUS underwater vehicle to ideal and real-world bathymetry models.

CIVINS / This thesis presents a simulation of autonomous underwater vehicle navigation using a single transponder to create a virtual long baseline (VLBL). Similarly to LBL systems, ranges in a VLBL are calculated between the vehicle and the transponder, but the vehicle position is determined by advancing multiple ranges from a single transponder along the vehicles dead reckoning track. Vehicle position is then triangulated using these successive ranges in a manner analogous to a 'running fix' in surface ship navigation. Navigation data from bottom survey operations of an underwater vehicle called the Autonomous Benthic Explorer (ABE) were used in the simulation. The results of this simulation are presented along with a discussion of the benefits, limitations, and implications of its extension to real-time operations. A cost savings analysis was also conducted based both on the idea that a single surveyed beacon could be deployed for underwater navigation and on the further extension of this problem that the 'single beacon' used for navigation could be located on the ship itself. / Contract number: N62271-97-G-0026. / CIVINS / US Navy (USN) author.

Thesis (M.S. in Operations Analysis)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Arnold H. Buss. Includes bibliographical references (p. 123-124). Also available online.

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2005. / Bibliography: p. 119-129.

Thesis (M.S.) Woods Hole Oceanographic Institution and the Massachusetts Institute of Technology, July 1996. / Includes bibliographical references (p. 69-71). Also available online.

Thesis (M.S. in Computer Science) Naval Postgraduate School, September 1996. / "September 1996." Thesis advisor(s): Robert B. McGhee, D.P. Brutzman. Includes bibliographical references (p. 225-226). Also available online.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Anthony J. Healey. Includes bibliographical references (p.65-66). Also available online.

Thesis (M.S. in Computer Science and M.S. in Electrical Engineering) Naval Postgraduate School, March 1996. / Thesis advisor(s): D.P. Brutzman, Xiaoping Yun. "March 1996." Includes bibliographical references (p. 55-56). Also available online.

is shown to follow an exponential distribution. These three models enable operators to explore the impact of various inputs prior to programming the vehicle, thus allowing them to choose the best combination of vehicle parameters that minimize the offset error between the reported and actual locations.

Acoustic modems are the basis for emerging undersea wireless communications networks. US Navy Seaweb technology offers an opportunity to perform undersea navigation and tracking by virtue of node-to-node ranging measurements acquired as a by-product of the acoustic communications protocol. A simple localization algorithm is developed and verified with synthetic data and is then tested with an Unmanned Undersea Vehicle (UUV) during an experiment at sea.