Abstract-Based on second-order cone programming, we present a new superdirective beamforming method with interferences and noise suppression for small aperture HF receive arrays. In the novel method, low side lobe level (SLL) and nulls are not only used to suppress interferences and noise, but also play an important part in overcoming the low array efficiency brought by superdirective beamforming. According to the actual condition, the new method can present a good tradeoff between directive gain, array efficiency, SLL, nulls and robustness against array uncertainty. Compared with the existing methods, it is more effective in suppressing interference and noise. The superiority and validity of the proposed method can be illustrated by numerical results.
Self-noise is a very disadvantageous factor for underwater glider to observe ocean ambient noise, in which the noise caused by motor is very significant. In order to grasp the characteristics of the motor-noise and its influence on the measurement of ocean ambient noise, a long-term sea trial was conducted in the South China Sea in May 2020, and the self-noise data of underwater glider under different working conditions are obtained. By analyzing the noise level and spectrum level of the motor noise, we obtained the self-noise spectrum characteristics and know that the influence of control motor noise on the noise measurement of head and tail hydrophone is mainly below 5 kHz band, and the influence of full-frequency noise level brought by motor is within 10dB and 5dB respectively. The results lay an important foundation for further analysis of ocean ambient noise measured by underwater glider.
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