등방성 소음환경에서 공간적 상관성을 이용한 배열이득 분석 및 시뮬레이션

Abstract

When an array of receivers is used in the ocean as a sonar system, compared to using a single receiver, there is a signal gain, which is called as Array Gain (AG). There are two methods to calculate the AG: One method is to use Signal to Noise Ratio (SNR), and the other method is to use spatial coherence.

In this thesis, AG is calculated and verified through Monte-Carlo simulation, assuming the isotropic noise and the perfect coherence of target signal in order to better understand the performance of an array of hydrophones. Spatial coherence of noise field was calculated through the cross-correlation coefficient of the signals received by two different receivers.

The contribution of this thesis is to summarize and to verify the existing algorithms to typical examples. Also, it is shown that the Directivity Index(DI) is the same as AG in isotropic noise for all frequencies.

In future study, two topics are suggested to be further explored. First topic is that the signal and noise are simulated in time domain, which can be directly applied to the development of the simulator in time domain. Second topic is to extend the complexity of the simulation to the real ocean, which includes the simulation of directional noise and the realistic spatial coherence of target signals.