ИСТИНА

Pipeline inspection systems (PIS) are used for oil and gas pipelines monitoring. PIS is placed in pipeline (diameter about 1 m) and moved by oil or gas stream. Unit velocity is about 1-5 m/s, time of movement may be several days. Inside the pipeline PIS is autonomous, which place restrictions on using accurate navigational sensors. Among these are inertial sensors – angular rate sensors (ARS), accelerometers and odometers. Strapdown Inertial Navigation System (SINS) is built on a basis of inertial sensors. Arising navigation task is solving in post processing mode. Additional information is made up by odometers and geodetic data of the reference points (or markers) location. Data support highlights: • moderate potential of the geodetic data - the distance between the adjacent markers is about 2-4 km; • the necessity to make use of inertial sensor with low or middle level of accuracy due to limitations on size and power supply; • big enough time of PIS operation mode – the duration of the PIS session may be more than 24 hours. The task of PIS navigation is formulated as the task of SINS correction in post processing. Information approach is used for navigation problem solution [1, 2]. In terms of mentioned approach the raw navigation information falls into basic part, provided by inertial sensors, and non-inertial additional information which is used for the estimation of the errors of a strapdown inertial navigation system (SINS) and other instrumental errors. Considering that time of SINS operation is large, the task must be solved in the so-called special feedbacks variant of the navigation equations [2].