Frequency domain compensation for failed elements in linear sonar arrays

In conventional beamforming applications, sidelobe attenuation and directivity are decreased when failed hydrophones are present in a sonar array. For sensitive design shadings (Hanning, Hamming), as a result of element failures, the sidelobes may be elevated as much as 50 dB in the deep sidelobe region. As a method of compensation for these beam pattern degradations, a frequency domain estimate of a missing element sequence can be obtained and used to complete the set of hydrophone sequences. When this method is employed it is shown that a global improvement of approximately 20 dB is obtained for sidelobe attenuation. This is true especially for sensitive shading schemes and even when uncorrelated noise is present in the environment.