Accurate Pipeline Surveying Using Two-Filter Optimal Smoothing of Inertial Navigation Data Augmented with Velocity and Coordinate Updates

Hang Liu, Sameh Nassar and Naser El-Sheimy

Abstract:	Pipelines are constructed to transport or dispose liquid and gases, commonly operated by oil, gas, sewerage and chemical industries. The pipeline system consists of three basic components namely gathering lines, trunk lines and distribution lines. Environmental, safety and economic concerns necessitate the constant monitoring of pipelines to avoid potentially hazardous failures. Currently, Pipeline Inspection Gauges (PIGs) can be sent through the pipelines to monitor the inside conditions. The Inertial Navigation System (INS) is employed to conduct the overall PIG navigation due to the unavailability of GPS signals inside the pipeline. Due to the time-dependent errors of INS only navigation, additional aiding sensors and/or auxiliary velocity and position updates need to be used to compensate for such errors. In addition, optimal smoothing methods are required since optimal smoothing is a post-mission estimator that provides the optimal estimates by using all available measurements. In this paper, two smoothers, namely Two-Filter Smoother (TFS) and the Rauch-Tung-Striebel Smoother (RTSS) will be implemented based on an Extended Kalman Filter (EKF). Using real pipeline inertial data collected with a tacticalgrade Inertial Measuring Unit (IMU), the effect of the additional velocity updates and available position updates will be shown. Moreover, the performance of both optimal smoothers will be evaluated. The combined implementation of the additional filter updates and smoothing demonstrated a remarkable improvement in the navigation accuracy compared to the original KF solution.
Published in:	Proceedings of the 2010 International Technical Meeting of The Institute of Navigation January 25 - 27, 2010 Catamaran Resort Hotel San Diego, CA
Pages:	49 - 56
Cite this article:	Liu, Hang, Nassar, Sameh, El-Sheimy, Naser, "Accurate Pipeline Surveying Using Two-Filter Optimal Smoothing of Inertial Navigation Data Augmented with Velocity and Coordinate Updates," Proceedings of the 2010 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2010, pp. 49-56.
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