A Rotating Permanent Magnets Positioning System for Laying Underground Pipelines

This study presents a novel system for accurately positioning underground pipelines by applying rotating permanent magnets, addressing the limitations of traditional wireless systems in effectively penetrating both the pipe and surrounding soil. The system is realized with the improved fingerprint matching algorithm, which is composed of a rotating structure, a permanent magnet, a magnetic sensor, an A/D module, and a positioning solution module. Under the boundary conditions, a continuous propagation model of the magnetic field is analyzed for the medium of different magnetic permeability, which is the basis of the positioning method in the pipelines. To solve the problem of difficulty in obtaining an accurate dense database, a methodology involving measurement and virtual reference points (RPs) is developed. A matching method based on cluster analysis is applied in the system to improve the matching efficiency, which includes cluster selection, coarse matching, and fine positioning. The realized prototype is used to verify the proposed approach in long metal pipelines, which have a maximum positioning error of less than 0.15 m, a mean value of 0.0974 m, and a standard deviation of 0.0106 m in a factory environment. This affirms the effectiveness of the developed system in addressing issues related to accurate pipeline localization.