Essential Limitations to Signal Detection and Estimation: An Application to the Arctic Under Ice Environmental Noise Problem

It has been observed that Arctic under ice noise is at times composed of narrowband components. The narrowband noise is primarily due to rubbing ice flows but possibly acoustic dispersion contributes to this phenomenon. This type of interference can significantly degrade the performance of systems w...

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Bibliographic Details
Main Author: Dwyer,R F
Other Authors: NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT NEW LONDON LAB
Format: Text
Language:English
Published: 1984
Subjects:
Snow
Ice and Permafrost
Acoustic Detection and Detectors
*ENVIRONMENTS
*ACOUSTIC DETECTION
*NOISE
*NARROWBAND
*UNDERICE
FREQUENCY
TIME INTERVALS
AUTOCORRELATION
ICE
SIGNALS
SOUND
INTERFERENCE
NAVAL RESEARCH
FAST FOURIER TRANSFORMS
STATISTICAL ANALYSIS
FUNCTIONS(MATHEMATICS)
ARCTIC REGIONS
LPN-NUSC-A75030
Arctic
Arctic Ocean
Ice
permafrost
Online Access:http://www.dtic.mil/docs/citations/ADA143828
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA143828
Description
Summary:It has been observed that Arctic under ice noise is at times composed of narrowband components. The narrowband noise is primarily due to rubbing ice flows but possibly acoustic dispersion contributes to this phenomenon. This type of interference can significantly degrade the performance of systems which estimate autocorrelation functions to obtain bearing and range information. The data were collected as part of the 1980 Arctic Ocean experiments. Many segments of Arctic under ice data contained these highly dynamic narrowband components as shown in Figure 1. The statistical behavior of the dynamic narrowband frequency components were measured by first transforming the data into the frequency domain using a fast Fourier transform (FFT). Then the Kurtosis was estimated for each real and imaginary part of each frequency component over the band for a group of consecutive FFT segments. This procedure is called frequency domain Kurtosis (FDK) estimation. Thus, the FDK estimates the distribution over a time interval consisting of many FFT segments for each real and imaginary frequency component. Many of the Arctic data segments showed non-Gaussian components in the frequency domain based on the FDK estimate. This was due mainly to the highly dynamic nature of the narrowband ice components. Therefore, the FDK is a method whereby the desired signal can be distinguished from the unwanted ice sound. Presented at the International Conference on Acoustics, Speech, and Signal Processing, 19-21 Mar 84, San Diego, CA.

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