DocumentCode :
393989
Title :
Adaptive beamforming in non-stationary environments
Author :
Cox, Henry
Author_Institution :
Orincon Corp., Arlington, VA, USA
Volume :
1
fYear :
2002
fDate :
3-6 Nov. 2002
Firstpage :
431
Abstract :
With moving interferers, there is a trade-off between statistical uncertainties if too few snapshots are used, and smearing of the eigenstructure of the sample covariance matrix (SCM) if too many snapshots are used. When the number of snapshots L that can be obtained before significant motion occurs is less than the number of elements M in the array, the SCM is rank-deficient. A discussion is given of the special problems in using rank-deficient SCMs. Frequently, extra information is available that is not contained in the sample covariance matrix. An estimate of the maximum number of significant eigenvalues is twice the array length divided by the acoustic wavelength. An estimate of the background level in the absence of interference is frequently available based on long-term observations. Under some circumstances the median eigenvalue of the SCM is a useful estimate of true background noise. In this paper, we examine the use of such auxiliary information to set the loading parameter of the rank-deficient SCM.
Keywords :
array signal processing; covariance matrices; eigenvalues and eigenfunctions; interference (signal); sonar arrays; sonar signal processing; acoustic wavelength; adaptive beamforming; array length; background level; background noise; eigenstructure; loading parameter; moving interferer; nonstationary environment; plane waves; rank deficient SCM; sample covariance matrix; significant eigenvalue; snapshot window; statistical uncertainty; Acoustic arrays; Acoustic beams; Acoustic waves; Array signal processing; Covariance matrix; Eigenvalues and eigenfunctions; Frequency; Robustness; Sonar detection; Uncertainty;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Signals, Systems and Computers, 2002. Conference Record of the Thirty-Sixth Asilomar Conference on
Conference_Location :
Pacific Grove, CA, USA
ISSN :
1058-6393
Print_ISBN :
0-7803-7576-9
Type :
conf
DOI :
10.1109/ACSSC.2002.1197220
Filename :
1197220
Link To Document :
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