Simulating the dynamic interaction of an AUV and towed magnetometer

A magnetometer with a sensitivity of 0.01nT will be towed through the thermocline by a 2.87 meter long, 0.533 meter diameter autonomous underwater vehicle (AUV) to measure the magnetic fluctuations generated by oceanic internal waves. At this point, no research has been found that suggests towed magnetometer measurements have been done using an AUV. Simulations of the AUV, tow cable, and towfish are performed to provide an understanding of the effects of changing different input parameters, such as towing speed (0.5-2m/s), cable length (5-15m), vehicle trajectory (circle and vertical zig zag maneuvers), and current (0.25-1.25m/s). The AUV-cabletowfish system and equations of motion needed for the simulations are described herein. Results show that a 5m tow cable provides better towfish maneuvering than the longer cable lengths. High towfish pitch angle is decreased by decreasing the distance between CG and CB. Surface currents speed of 0.25m/s change the AUV and towfish circle maneuver to a spiral trajectory, while 1.25m/s current speed cause a zig zag trajectory.