A novel algorithm for acoustic above ground marking based on function fitting

Magnetic Flux Leakage detector (MFL_PIG) is widely used in long-range pipeline inspection. Acoustic above ground marking device is an important part of the location system in the MFL_PIG. A novel above ground marking algorithm based on function fitting is proposed to reduce marking error of above ground markers (AGMs). Experiments were carried out on a 2.5 km long pipeline on site. The results demonstrate that the function fitting algorithm has higher precision and anti-interference ability than traditional marking method-extreme value algorithm, and it works very well when SNR of the signal is greater than −2 dB.