ONMARK ABOVE GROUND MARKER SYSTEM
The OnMark AGM System is deployed along the pipeline right of way spaced every 1 to 2km. This device, when active, looks for the magnetic signature produced by the strong permanent magnet in any inspection or gauging tool and records the time at which the tool passes underneath. These passage times are retrieved from the OnMark AGM System and entered into the final report as above ground reference positions. This effectively divides the pipeline up into shorter sections making feature location easier.
TIMING IS RIDICULOUSLY IMPORTANT
Because the OnMark AGM System records times of passages to be later correlated back to the internal clock in the Inspection System the accuracy of the clocks in both systems is very important. Both GPS synchronized units use the same highly accurate clock module which features a temperature compensated crystal to ensure, no matter the temperature, reliable results.
LOCATION, LOCATION, LOCATION
OnMark AGMs also record the latitude, longitude and elevation for each site using their onboard GPS receiver. The location information is then imported into Streamview for inclusion in the inspection report. This allows the marker location to be easily located months and even years down the road.
FILTERS REDUCE FALSE TRIGGERS
Employed in the design of the OnMark AGM System are advanced algorithms which allow the system to reliably distinguish between background noise and the real inspection tool passages. When the unit is switched on it closely monitors the magnetic fields in the vicinity. The unit then automatically adjusts its sensitivity to match the noise level of the surrounding environment. The unit even has the ability to determine if the location is unacceptable to record a passage and prompts to user to move to a more acceptable location.