For maintenance purposes pipelines have to be checked on a regular basis with the help of inspection tools searching for damage such as deformation, corrosion or leaks. During this inspection it is especially important to determine the exact location of the inspection tools in the pipeline, as this can significantly reduce the scope of neces­sary repairs. Inaccurate location of the damage can make it necessary to clear a large area of the pipe­line, result­ing in much higher repair costs.
With the help of Inertial Navi­ga­tion Technology the position of a pipeline inspection tool in a pipeline can be exactly de­termined. To achieve this, the inspection tool is coupled with an in­er­tial Pipeline Surveying Tool (iPST) con­sisting of three gyro­scopes, three accel­erometers, odo­meters and an electronic device for signal process­ing. The gyro­scopes are used to de­termine atti­tude and heading of the iPST. The acceler­ome­ters and the odometers are used to deter­mine the transla­tional mo­tions. All data are proc­essed using a filter which also per­mits addi­tionally avail­able ex­ternal aiding in­for­mation for data proc­ess­ing.
The iPST-FMS contains fiber optical gyros of class 1 deg/hr. The di­ameter and length depends on the envi­ronmental condi­tions. The accel­er­ometers used have 5 g range and 10 µg resolu­tion.

Technical Data of iPST-FMS (brief):

• iPST-FMS-E with three fiber optic gyroscopes
• range +/- 400 deg/s, bias 1°/h
• ARW 0.1°/, linearity 300 ppm
• three servo ac­cel­ero­me­ters (range +/- 5 g, resolution 10 µg, bias 2 mg)
• Size: Ø 120 mm, L 380 mm (other on request)
• connection for up to 3 odometers
• internal data storage for up to 128 GByte available
• accuracy: < 1...2 m over 1...2 km aiding
• postproc calculation of navigation results
  

Comparable systems are available based on higher performance ring-laser gyros (iPST-RQH).

The post-processing software iPosCAL-PST is available for operators and maintenance organizations of pipelines to process the acquired inertial / odometer / marker data and to obtain the required trajectories.