Pipeline Defects Localization Based on INS and Shielded Geomagnetic Field

To locate pipeline defects, a method based on inertial navigation system (INS) and shielded geomagnetic field (SGF) is proposed. The equations for the clock localization of pipeline defects are deduced, which greatly improve the theory of the pipeline defects localization method. Then, an error compensation method of INS based on SGF is proposed. In this method, SGF is measured by the triaxial magnetometer which runs synchronously with INS, and the magnetometer attitude can be calculated according to SGF, so as to realize the re-detection of the pig attitude and the error compensation of INS. Simulations are carried out to analyze the influences of the engineering factors on the error compensation method. Finally, the effectiveness of the error compensation method is verified by experiments, and the results show that the error range of the attitude obtained by the method is: 0.02°-13.34°, and the mean error is 4.62°, which meets requirements of engineering practice.