| A unique application of strapdown inertial technology has been developed for deformation monitoring of operating pipelines. The instrumented system called a Geometry Pig determines position, orientation, curvature, ovality, and deformations such as dents and wrinkles of oil and gas pipelines. At the heart of this integrated system is a Strapdown Inertial Navigation System which is integrated with velocity and distance sensors, caliper sensors, weld detection system, and digital recording device. The geometry pig is designed to operate continuously and autonomously in operating fluid or gas pipelines. The study presents the motivation, design concepts, system description, mathematical models for processing inertial and other sensor data, and an analysis of the capabilities. Results from operating oil pipelines are presented which demonstrate the accuracies obtained meet or exceed the requirements for pipeline geometry monitoring. |
