Coherent multipath signal direction finding with array shape distortion

When the shape of a horizontal towed line array is deformed due to fluctuations in ship maneuvering, beamforming and Directions-of-Arrival (DOA) estimation would be critically degraded if the array shape was still assumed to be a straight line. An effective method was proposed to estimate the DOAs of the coherent multipath signals with the deformed towed array. Firstly, the spatial signature is blindly estimated from the eigen-decomposition of the data covariance matrix. Then, the problem of DOAs estimation could be described as a nonlinear multi-dimensional optimization problem and solved by the Genetic Algorithm, which dose not require the initial values of the parameters and can converge to the global point. The effectiveness of the proposed method was verified by numerical examples.