Underwater Tone Detection with Robust Coherently-Averaged Power Processor

Abstract

The detection of tonal signals with unknown frequencies is an important area of study in underwater signal processing. A common approach to address this issue is to use the Discrete Fourier Transform (DFT) for observations. When a tone does not lie precisely at the discrete DFT frequency point, its energy will leak to adjacent frequency point. This phenomenon is known as scalloping loss or Picket Fence Effect (PFE). PFE leads to the degradation of detection performance based on DFT. This paper studies the problem of robust detection in the case of PFE. A coherently-averaged power processor utilizing the information of adjacent frequency bins is designed. The results of simulations and experiments show that the proposed method is robust against PFE, and is highly suitable for tone detection in practical circumstances.

Beat-Notes Acquisition of Laser Heterodyne Interference Signal for Space Gravitational Wave Detection

“…The design of the LISA frequency acquisition algorithm for the carrier beat-note was based on FFT [ 3 ]. However, due to the picket fence effect and spectrum leakage of the discrete spectrum [ 9 , 10 ], the frequency error is large [ 11 ], and can not meet the requirements of high accuracy. Taiji Plan is a space gravitational wave detection plan proposed by China Academy of Sciences.…”