A towed underwater vehicle equipped with a bio-inspired artificial lateral line (ALL) was constructed and tested with the goal of active detection and correction of the vehicle's yaw angle. Preliminary experiments demonstrate that a low number of sensors are sufficient to enable the discrimination between different orientations, and that a basic proportional controller is capable of keeping the vehicle aligned with the direction of flow. We propose that a model based controller could be developed to improve system response. Toward this, we derive a vehicle model based on a first-order 3D Rankine Source Panel Method, which is shown to be competent in estimating the pressure field in the region of interest during motion at constant angles, and during execution of dynamic maneuvers. To solve the inverse problem of estimating the vehicle orientation given specific pressure measurements, an Unscented Kalman Filter is developed around the model. It is shown to provide a close estimation of the vehicle state using experimentally collected pressure measurements. This demonstrates that an artificial lateral line is a promising technology for dynamically mediating the angle of a body relative to the oncoming flow. Michael Triantafyllou, who has supported and guided me throughout my thesis while encouraging me to work my own way. With his patience and knowledge, and impressive ability to draw ideas together into elaborate and inspiring pictures, he has been a powerful source of both guidance and inspiration. I would also like to thank the number of other professors and research scientists at MIT who have helped me along the way -in particular, Prof. David Trumper for his help in resolving the electrical noise issues within my experiment, and Yuming Liu for his help with the formulation of my panel method simulation.In my daily work I have been blessed with a friendly and cheerful group of fellow students and labmates. I would like to say a huge thank you especially to members of the Tow Tank Lab, Heather, Jeff, Audrey, James, Steph, and Jacob. The number of stimulating intellectual conversations we had both brightened my days and kept me thinking. Thank you also to Dr. Jason Dahl, who provided valuable advice in the brainstorming phase of this project and experimental design, and to our colleagues over in Singapore, who have offered helpful advice during our meetings.Finally, I would like to express my love and indebtedness toward my family and my friends. To my dear parents, Tracy and Johnway Gao, thanks for bearing with me through all the happy times and all the hard times, and being a constant source of support and encouragement. I couldn't have done it without you guys! Thanks also for taking me tuna fishing. To my twin brother Allan -my lovable squishy, thanks for always being there for me, for advice, good stories, and good times. To Leah -thanks for always being there to listen and for helping me through many of the most difficult times of the last two years. And last but certainly not least, thanks to my bo...