In this study, the dynamic analysis of Pipeline Inspection Gauge (PIG) flow control innatural gas and liquid pipeline is considered. The basic equations are differential formsof the mass and linear momentum for compressible liquid and gas flows. The fluid flowequations and a linear momentum equation of the PIG are solved simultaneously using anappropriate numerical method. Solution of these nonlinear equations results in a set ofdiagrams for the variations of the fluid pressure, mass flow rate of the gas and the PIGvelocity through the pipeline. Comparing the results of mathematical model for the PIGwith the established experimental data in a segment of Ahwaz gas pipeline shows a goodagreement between the measurements and computations.

The paper discusses the development of an adaptive Kalman filter for pipeline surveying applications. Various measurement models are developed and numerically tested using a real natural gas pipeline dataset. Since, for tactical-grade IMUs, odometer-derived velocity measurements alone cannot yield good results, two non-holonomic constraints are augmented to make the three-direction measurement model. Smoothing computation is also applied to yield the best trajectory using all the information contained in the past, current and future measurements. The trajectory errors are within 10–20 m for extreme cases, and within 10 m for most cases. RMS of the trajectory errors is expected to be about 2·5 m.