Array shape estimation based on tug vehicle noise for towed linear array sonar during turning

In almost every practical scenario, the shape of towed linear array (TLA) is always affected by current, tug vehicle speed, and other factors, resulting in the deviation of sensor positions. Furthermore, maneuvers bring significant changes to array shape, i.e., array mismatch, which will greatly degrade the performance of array processing system. To deal with this problem, this paper first establishes a hydrodynamic model to fit the law of motion of turning cables. Then, a time difference of arrival (TDOA) method is utilized to estimate the real-time array shape, which exploits the near-field tug vehicle noise. Finally, the array shape is estimated by combining the hydrodynamic model and the TDOA method. The simulation results exhibit that the proposed array shape estimation method can resolve the array mismatch problem when turnings happen. Compared with the state-of art array shape estimation methods, this paper provides similar estimation accuracy without extra gyros or auxiliary sources. The lake trial results validate its feasibility and stability for estimating far-field target bearings in practical applications.