AUV pipeline inspection using magnetic tomography

A remote device for integrity management of a surveyed underwater structure, comprising:

• an independently powered body for moving underwater in an autonomous manner, at least three Magnetic Tomography Method (MTM) sensors, said sensors registering MTM signals, said registering being based on the Villari effect, said signals occurring continuously and naturally as a result of the Earth's magnetic field, transmitting through said structure, and being continuously received by each MTM sensor as said device nears, reaches, and departs from every point of said structure, wherein said at least three MTM sensors are positioned such that at least three MTM sensors lie on at least two separate horizontal cross sections of said body of the device, wherein those sensors which lie on one horizontal cross section are equally distant from all other sensors lying on the same horizontal cross section, and wherein at least one horizontal cross section comprises at least three sensors,
• a processing unit for receiving and interpreting said signals from said sensors, said processing unit converting the signals received and mapping a defect distribution along a length of said structure, and
• a means for tracking a location of a mapped defect,
• thus providing offline monitoring and risk evaluation of said structure.