Fast Fourier Transform Overlap Approach for Underwater Acoustic Positioning System

Acoustic technology able to provide communication between the surface vessel to the underwater vehicle. It helps especially during underwater navigation, tracking, localization and target positioning. This paper proposes a positioning system by using Fast Fourier Transform (FFT) with overlap technique. The FFT overlap is used to estimate the location of underwater target. Digital signal processing (DSP) algorithms are utilized on this system for extracting the information of the signal. Time difference of arrival (TDOA) is computed by retrieving difference between max FFT overlap of 2 different receivers, and it is multiplied by a constant which varies with overlap percentage. The peak amplitude is determined by computing FFT with 100% overlap. The location of target is determined by using angle estimation technique. This approach is tested on shallow water to obtain the direction of target. Result shows significant performance from the proposed approach.