Higher order moment detection of transients in measured shallow-water noise

A comparison between second and fourth order moment detectors is made for three low frequency transient signals embedded in measured ambient shipping noise from a shallow-water area. Detector evaluations must be made over short periods of time because of the nonstationary nature of the noise. Results indicate that the fourth order moment detects better than the second order moment for the two nonGaussian transient signals, but not as well for the more Gaussian transient signal. This suggests that the fourth order moment detector be used in addition to the second order moment detector, rather than as a replacement. The results of detection simulations with independent Gaussian noise are given for comparison to the results with the measured shipping noise. The comparison indicates that gains for the fourth order moment detector over the second order moment detector are higher in the shipping noise than in the Gaussian noise for the two nonGaussian signals.