Inertial Measurement Unit (IMU) is the core sensor in pipeline inertial measurement systems, which performs autonomous inertial measurement without external signal interference, especially for underground non-metallic pipeline measurement that cannot be solved by other methods. On the premise of providing the center coordinates of the pipeline head and tail to be tested, the motion trajectory of the pipeline instrument can be calculated through multi-source data fusion processing, thereby calculating the three-dimensional position, posture, and geometric parameters of the underground pipeline.

This method is not affected by pipeline material, burial depth, ground conditions, and electromagnetic fields around the pipeline, and can obtain continuous and accurate three-dimensional coordinates and postures of the pipeline. For pipelines laid by non excavation horizontal directional drilling, it overcomes many constraints of traditional measurement methods.