Abstract:

A comparison between second- and fourth-order moment detectors for passive detection of low-frequency transient signals in both uncorrelated Gaussian and measured noise is presented. The measured noise, recorded in shallow water near the San Diego harbor, is dominated at low frequencies by ship-generated noise and is thus correlated in time and between sensors. The detectors do not assume noise or signal stationarity and use two channels of data to form the second-order moment, and two or four channels of data to form the fourth-order moment. Detection simulations with test transients of varying kurtosis reveal that in the Gaussian noise, the fourth-order moment detector with two channels of data performs best only for signals with high kurtosis. However, in the measured noise, the fourth-order moment detector performs best for most of the test signals if four channels of data are included. If knowledge of the signal passband is included in the processing and detection is restricted to be within the passband, the fourth-order moment detector with four channels of data generally performs best in both the Gaussian and measured noise. [This work was funded by the Office of Naval Research.]