Tunnel Effect in Multi-beam Bathymetry Sonar and Its Canceling with Error Feedback Lattice Recursive Least Square Algorithm

The appearance of artificial false data would affect the detection accuracy in multi-beam bathymetry sonar and then lead to distortion of seafloor structure. The tunnel effect caused by side lobe interference has an important effect on the bathymetric results and it would mistake relatively flat seafloor for concave-up half cylinder characteristic. The tunnel effect is prominent when the seafloor is relatively flat. The side lobe interference could be eliminated through adaptive side lobe interference canceling based on the error feedback lattice recursive least square (EF-LRLS) algorithm with directly updating coefficients, the experimental results indicate that the error feedback algorithm could eliminate the side lobe interference efficiently and track the actual seafloor backscattering returns quickly.