ZHU Daizhu1,2 DU Xuanmin1

(1 Shanghai Marine Electronic Equipment Research Institute Shanghai 201108)

(2 School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiaotong University Shanghai 200240)

Received Apr. 15, 2009

Revised May 18, 2009

Abstract The energy ratio of broadband signal is utilized for port/starboard discrimination in towed line array with hydrophone triplets in tradition.It works well in most conditions except for two cases: One is low signal to noise ratio(SNR),and the other is that there is a stronger interference lied on the other side of the line array with approximate bearing angles.A method called line-spectrum character extracting is proposed to discriminate port/starboard for these two cases in this paper,and the SNR needed for port/starboard discrimination is reduced significantly.Simulation and the sea-trial data are analyzed to show that the method is stable and valid,and is expected to be applied in real towed line array sonar.A line-spectrum enhancing technology with lower calculation complexity and stable validity is proposed to ensure the application of this method in lower SNR condition.

PACS numbers: 43.30, 43.60