WU Guoqing1 WANG Meigang2
??1 Institute of Acoustics, The Chinese Academy of Sciences Beijing 100080??
??2 Engineering College of Shanxi University Taiyuan 030013??
Received Apr. 13, 2006
Revised Aug. 8, 2006
Abstract This work aims at sparse array without grating lobe for passive sonar, in order to increase frequency band of the passive sonar and reduce the cost. According to traditional method, the distance between two contiguous sensors in sonar array should be less than the wavelength of highest frequency of the signal; otherwise the grating lobe appears on beam pattern. The paper realizes that the conclusion of the grating lobe emergence it is not fit to the passive sonar due to the sine wave signal model in traditional method, in fact the input of passive sonar is random signal. From there aspect of the computer simulation, real passive sonar signal and theory analysis, it is revealed that the grating lobe dose not appear on beam pattern when the distance between two contiguous sensors in passive sonar array is longer than wavelength of highest frequency. Whitening of the radiated noise can widen the frequency band, to ensure the beam pattern without the grating lobe. The conclusion of the paper is: if the band of radiated noise is wide enough (broader than 1 octave), that the wavelength of signal can be shorter than the distance between two contiguous sensors in passive sonar without grating lobe.
PACS number: 43.30, 43.60