Dual-array localization of vibroacoustic source for leaks in buried gas pipelines

To accurately locate leaks in buried gas pipelines, a dual-array localization method of eigenspace-based DOA estimation was proposed to detect the leak-induced vibroacoustic signals with the ground-mounted accelerometer array, identify the ground markers and obtain the depth of the leak source. The minimum variance distortionless response beamforming algorithm was introduced to conduct spatial filtering for the array signal, so as to eliminate the reverberation interference in the finite experimental space. Under the experimental soil conditions, the frequency of the leak signals ranges from 200 Hz to 700 Hz and the P1 wave speed is 1 108 m/s. After filtering on the reverberation signal, the source directions can be accurately estimated with the arrays at different locations, for which the root mean square error is kept lower than 1° at the SNR of-3 dB. When the leak source is located in front of the second array, the calculation errors of the marker distance and leak source depth are found lower than 0.06 m and 0.04 m respectively at the SNR of-3 dB, and accurate localization can be achieved by properly adjusting the array location. The locating accuracy of the dual-array localization method is higher than that of the single-array locating method, with the localization error reduced by 79.45% on average, which is helpful to identify and verify the microleak points of buried gas pipelines, and ensure the safe operation of pipelines.