Improving the accuracy of in-pipe navigation in conditions of seasonal soil movements

The urgency of identifying potentially dangerous pipeline sections that are subject to a change in their position is shown. The existing methods of solving the problem of determining the pipeline offsets are described. The advantages and disadvantages of the described methods are analyzed. The results of the development of a new method for determining the pipeline displacements are presented. The method is proposed taking into account the existing technology of operation of oil pipelines and gas pipelines, as well as taking into account available inertial sensors and other sensors of primary information of measuring systems of the in-tube device. The relevance of the assessment of changes in the angular position of the pipeline axis by means of in-pipe navigation is shown with the purpose of identifying potentially hazardous areas that require monitoring of the change in the stress-strain state. Errors of the inside-tube mobile device with odometric, inertial and profile-metric measuring systems are described, namely: slippage of an odometer over the surface of the pipe, angular displacement of the longitudinal axis of the in-tube mobile device relative to the axis of the pipeline, ballistic error of the orientation system. Methods for identifying and compensating for errors in the measuring systems of the in-tube device for determining pipeline offsets are described. Within the framework of the proposed method for determining the pipeline displacements, the following approaches to countering the errors in the measuring systems of the in-tube mobile device are proposed: to compensate for the slippage of the odometer, information is used to measure the lengths of the same pipeline sections, obtained from the multiple passes of the in-tube device through the pipeline; To compensate for the angular displacement of the in-tube device, use a profilometric system with two belts of radial distance meters; to compensate for the ballistic error of the orientation system, speed and acceleration estimates obtained from the odometer system signals are used, taking into account the time between the odometer signals. The examples of the biased potentially dangerous sections of pipelines identified by the proposed method are given.