Research on the describing of trajectory for subsea pipeline based on Inertial Navigation System

Due to the variance of seabed geology appearance, it is difficult to provide accurate and real time geographic information for shallow sear subsea pipelines. Therefore, it is impossible to locate the defects of the pipelines; leading to the reparation hard to be performed. The describing of trajectory and location of defects based on INS (inertial navigation system) will be discussed in this paper. By analyzing the longitude and latitude location of the pipeline route, the relative locations of defects on the inner surface of pipelines to the geographical coordinate system can be determined. Error analysis and correction were done based on the results of laboratory testing. Field tests were also performed for offshore oil pipelines and results showed that the acquired data met errors requirements. Analysis and experiments results proved that using INS to solve the defect location and pipeline trajectory describing were accurate and feasible.