Line spectrum of ship noise and high-resolution direction-of-arrival estimation method of FFTSA passive synthetic aperture technology

Bearing resolution of towed linear array is an important performance index, which is restricted by the physical aperture of towed linear array. To be aimed at this problem, this paper raised out a new method: Using stable line spectrum of ship noise in the low frequency band to expand the effective aperture of towed linear array through FFTSA passive synthetic aperture algorithm, thus to improve bearing resolution greatly. If the integral time required by FFTSA is smaller than the time coherence length of the ocean acoustic channel, it can expand the effective aperture of towed linear array to any size smaller than the space coherence length of the ocean acoustic channel. After simulation, this method's algorithm is simple, easy to be put into practice, and can improve bearing resolution of towed linear array greatly. It is a high-resolution direction-of-arrival estimation method that has a bright future.