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Current rates of technological advancement continue to translate into changes on our battlefields. Aerial robots capable of gathering reconnaissance along with unmanned underwater vehicles capable of defusing enemy minefields provide evidence that machines are playing key roles once played by humans within our military. This thesis explores one of the major problems facing both commercial and military UUVs to date. Successfully navigating in unfamiliar environments and maneuvering autonomously to avoid obstacles is a problem that has yet to be fully solved. Using a simulated 2-D ocean environment, the work of this thesis provides results of numerous REMUS simulations that model the vehicle's flight path over selected sea bottoms. Relying on a combination of sliding mode control and feedforward preview control, REMUS is able to locate obstacles such as seawalls using processed forward look sonar images. Once recognized, REMUS maneuvers to avoid the obstacle according to a Gaussian potential function. In summary, the integration of feedforward preview control and sliding mode control results in an obstacle avoidance controller that is not only robust, but also autonomous.

Thesis (M.S. in Modeling, Virtual Environments and Simulation (MOVES))--Naval Postgraduate School, March 2004. / Thesis advisor(s): Christian Darken, Curtis Blais. Includes bibliographical references (p. 103-104). Also available online.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Anthony J. Healey. Includes bibliographical references (p. 79). Also available online.

Approved for public release, distribution unlimited / The Anti-Submarine Warfare screen design simulation is a program that provides a model for operations in anti-submarine warfare (ASW). The purpose of the program is to aid ASW commanders, allowing them to configure an ASW screen, including the sonar policy, convoy speed, and the number of ships, to gain insight into how these and other factors beyond their control, such as water conditions, impact ASW effectiveness. It is also designed to be used as a training tool for ASW officers. The program is implemented in Java programming language, using the Multi Agent System (MAS) technique. The simulation interface is a Horizontal Display Center (HDC) which is very similar to a MEKO200 class Frigate Combat Information Center's (CIC) HDC. The program uses Extensible Markup Language (XML) files for reading data for program scenarios; parameters are initialized before each run time begins. The simulation also provides all the output data at the end of run time for analysis purposes. The program user's goal, and the purpose of the program, is to decrease the number of successful attacks against surface vessels by changing the configuration parameters of the ASW screen, to reflect sonar policy, convoy speed or number of ships in the simulation. Ongoing use of the program can provide data needed to anticipate required operational needs in future ASW situations. / Lieutenant Junior Grade, Turkish Navy

In this research work we propose a 3D node deployment strategy by carefully considering the unique characteristics of underwater acoustic communication as well as 3D dynamic nature of UWSN. This strategy targets 3D UWSN and not only improves the routing protocol performance significantly in terms of end to end delay and energy consumption but also provides reliability in data transmission. This strategy has been developed step by step from a single line of vertical communication to an effective 3D node deployment for UWSN. Several simulation experiments were carried out after adding different features to the final design to observe their impact on the overall routing performance. Finally, it is verified that this design strategy improves the routing performance, provides reliability to the network and increases network lifetime. Furthermore, we compared our results to the random node deployment in 3D, which is commonly used for analysing the performance of UWSN routing protocols. The comparison results verified our effective deployment design and showed that it provides almost 150% less end-to-end delay and almost 25% less energy consumption to the random deployment. It also revealed that by increasing the data traffic, our 3D node deployment strategy has no loss of data due to several back-up paths available, which is in contrast to random node deployment, where the packet loss occurs by increasing the data traffic. Improving the routing performance by carefully analysing the impact of 3D node deployment strategy and ensuring full sensing, transmission and back-up coverage in a highly unpredictable underwater environment, is a novel approach. Embedding this strategy with any networking protocol will improve its performance significantly.