A localization method for subsea pipeline based on active magnetization

Abstract

Accurate localization of subsea pipelines is the prerequisite of real-time tracking and elaborate inspection by underwater robots. Magnetic anomaly generated by the ferromagnetic pipeline can be used to locate both uncover and buried pipelines. However, due to low signal ratio and model inconstancy under weak and variable ambient magnetization, there is still missing an intuitive and reliable pipeline localization method in order to realize pipeline tracking. This paper proposes a method capable of immediately and accurately locating pipelines via active magnetization and vertical magnetic measurement. Finite element simulation shows that magnet array can significantly enhance the magnetic anomaly, and the vertical magnetic component alone can accurately indicate pipeline position, avoiding the inconvenience of magnetic three-component alignment in field. It is experimentally demonstrated that magnetic detection SNR can be significantly increased by 5dB~20dB for a Φ219mm steel pipe by using the magnet array, and the max lateral positioning error is 0.03m and much smaller than that without magnet.

Eigenvector Constraint-Based Method for Eliminating Dead Zone in Magnetic Target Localization

“…As regards selecting the penalty coefficient, the L-curve method a commonly used method in Tikhonov regularization. This method graphically determines the optimal penalty coefficient by plotting the trade-off between the solution norm v T 2 r 2 2 and the residual norm Gr + 3B 2 2 . As the penalty coefficient changes, the regularized solutions are computed, and the norms are plotted, forming an L-shaped curve.…”

“…From the Figure 6, it is evident that the curve exhibits a distinct L-shape. Moreover, the elbow of the L-curve is positioned where the residual norm Gr + 3B 2 2 is about 3.71 × 10 −9 and the solution norm v T 2 r 2 2 is about 3.40 × 10 −15 . At this point, a balance between the solution norm and the residual norm is achieved.…”

“…Magnetic target localization technology has significant practical applications in various fields. For instance, in underwater magnetic localization, it aids in mapping the undersea terrain and identifying buried magnetic objects [1,2]. It is also employed in detecting unexploded ordnance, where it helps identify and safely remove potential threats [3,4].…”

A novel non-contact, magnetic-based stress inspection technology and its application to stress concentration zone diagnosis in pipelines

“…Zhao et al [28] proposed a collaborative inspection strategy for pipelines in oil and gas stations by using non-contact PMSI technology and other NDT technologies. Huang et al [29] proposed a method capable of immediately and accurately locating pipelines via active magnetization and vertical magnetic measurements. The signal-to-noise ratio of the magnetic detection can be significantly improved by 5 dB to 20 dB after using a magnet array.…”