More accurate measurement: three consecutive years than the measurement accuracy;

Smaller size: measurable DN90 PE tube;

Longer endurance: more than 12 hours of single endurance;

More complete functions: can locate the weld, can calculate the curvature of the pipeline;

More stable operation: not afraid of weld impact, more adaptable;

The algorithm is more intelligent: back and forth, short stay can be successfully solved;

More convenient connection: integrated direct connection, get rid of cable trouble;

The interaction is more intimate: the original U disk and key interaction are not restricted by the working space.

For the pipeline line measurement of trenkless pipe jacking construction, conventional electromagnetic pipeline instrument, ground penetrating radar and other instruments are limited by many factors such as electromagnetic interference, pipe material, buried depth of the pipeline, etc., which may easily lead to unsuccessful or discontinuous measurement, unable to obtain a complete three-dimensional attitude trajectory of the pipeline, and very low construction efficiency, especially in the measurement application of river crossing pipelines. These instruments are even more hopeless. The pipeline 3D attitude measuring instrument based on the principle of inertial measurement is to obtain its motion trajectory through professional calculation of the measurement of physical information such as angular velocity, inclination Angle and acceleration during its operation. As long as its motion trajectory coincides with the pipeline, the three-dimensional attitude quantity distributed underground in the pipeline can be obtained. It is not affected by external electromagnetic and pipe material, buried depth and other factors, and continuous measurement, high measurement accuracy.

Field condition

The measured gas pipeline is a medium pressure natural gas pipeline connection project of a gas company in Fujian Province. The pipeline material is 20#3PE reinforced anticorrosion steel pipe φ610, the length of the pipeline is 735 meters. According to the guidance measurement results during construction, the depth of the pipeline is more than 30 meters

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Measurement process

According to the site situation, we prepared a DT-GXY-200 host, a GNSS RTK set of auxiliary measuring equipment suitable for the center line positioning at both ends of the pipeline, 2 electric winches, 4 engineering surveying personnel, and carried out 3 round-trip measurements (the actual demand only 1-2 times), which took 1.5 hours (traction speed of about 1m/s).

Measurement data analysis

The total length of the pipeline is 733.98m (related to the sampling point interval), the buried depth is 31.38m, the three measurement track lines are basically the same, and the maximum space spacing of the three track lines is 2.52m, which basically conforms to the nominal accuracy of the instrument. From the comparison of the three measurements, since the inertial measurement unit is a gravity sensitive element, and the time bias (course deviation becomes larger with the increase of time) is significant, so in the traction process, the impact on the instrument should be minimized during the measurement process, followed by the allowable traction speed range, the measurement time should be minimized, especially for long distance pipelines.