Magnetic survey and autonomous target reacquisition with a scalar magnetometer on a small AUV

Abstract

A scalar magnetometer payload has been developed and integrated into a two‐man portable autonomous underwater vehicle (AUV) for geophysical and archeological surveys. The compact system collects data from a Geometrics microfabricated atomic magnetometer, a total‐field atomic magnetometer. Data from the sensor is both stored for post‐processing and made available to an onboard autonomy engine for real‐time sense and react behaviors. This system has been characterized both in controlled laboratory conditions and at sea to determine its performance limits. Methodologies for processing the magnetometer data to correct for interference and error introduced by the AUV platform were developed to improve sensing performance. When conducting seabed surveys, detection and characterization of targets of interest are performed in real‐time aboard the AUV. This system is used to drive both single‐ and multiple‐vehicle autonomous target reacquisition behaviors. The combination of on‐board target detection and autonomous reacquire capability is found to increase the effective survey coverage rate of the AUV‐based magnetic sensing system.

Three-dimensional coil system for the generation of traceable magnetic vector fields

“…Magnetic field sensors with 3D sampling capabilities play an increasing role in modern industrial and consumer applications (Lenz and Edelstein, 2006), e.g., space, naval and airborne navigation (Schonstedt and Irons, 1949;Acuña, 2002;Page et al, 2021), position control, and upcoming autonomous driving (Patel and Ferdowsi, 2009;Gallimore et al, 2020). Depending on the underlying measurement method, they exhibit either high levels of sensitivity, precision, and accuracy to the magnetic flux density or excellent spacial and directional resolution.…”

Compact Quantum Magnetometer System on an Agile Underwater Glider

“…Magnetometers have been towed behind surface ships, incorporated in large Remote Operated vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs), and are used for purposes ranging from geophysical and biological research to anthropogenic undersea target detection [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. For example, anthropogenic targets are strongly suspected if an object is detected in sonar/visual-based methods and has a strong magnetic signal.…”

“…For example, anthropogenic targets are strongly suspected if an object is detected in sonar/visual-based methods and has a strong magnetic signal. Shipwrecks, aircraft wrecks, Mine-Like Objects (MLOs) and unexploded ordnance (UXO) can be localized and classified via a fusion of magnetometry, sonar, and visual inspection methods [ 4 , 5 , 9 , 10 , 11 ].…”

“…As AUVs have advanced in recent years, so have compact, low-power optical magnetometers [ 25 ]. These systems have enabled the utilization of small AUV/ROV systems for magnetic surveys [ 4 ]. Optical magnetometers offer high-precision, calibration-free measurements of the Earth’s magnetic field and distortions of that field due to the presence of magnetic objects.…”

“…Platform sources of magnetic noise can be reduced by keeping the magnetometer far from the noise source (e.g., on a tow cable [ 26 ]), but this increases the size of equipment required, reduces maneuverability, and increases the power consumption due to locomotion. Software compensation can be effective at reducing motion-related platform noise due to platform static magnetization, induced magnetization, and eddy currents [ 4 , 17 ].…”