DocumentCode :
1104319
Title :
Fundamental limitations in passive time-delay estimation--Part II: Wide-band systems
Author :
Weinstein, Ehud ; Weiss, Anthony J.
Author_Institution :
Tel-Aviv University, Tel-Aviv, Israel
Volume :
32
Issue :
5
fYear :
1984
fDate :
10/1/1984 12:00:00 AM
Firstpage :
1064
Lastpage :
1078
Abstract :
This is the second part of a study which deals with the problem of passive time delay estimation. The focus here is on systems employing wide-band signals and/or arrays of very widely separated receivers. A modified (improved) version of the Ziv-Zakai lower bound (ZZLB) is used to analyze the effect of additive noise and signal ambiguities on the attainable mean-square estimation errors. When the lower bound is plotted as a function of signal-to-noise ratio (SNR), one observes two distinct threshold phenomena dividing the SNR domain into three disjointed segments. At high SNR, the lower bound coincides with the Cramér-Rao lower bound (CRLB). This is the ambiguity-free mode of operation where differential delay estimation is subject only to local errors. At moderate SNR (between the two thresholds), the lower bound exceeds the CRLB by a factor of 12(ω0/w)2where \\omega _{0} and w are, respectively, the center frequency and signal bandwidth. In this region, the ambiguities in the received signal phases cannot be resolved; however, a useful estimate of the differential delay can still be obtained using the received signal envelopes. At low SNR, the lower bound approaches a constant level depending only on the a priori search domain of the unknown delay parameter. In this region, signal observations are subject to envelope ambiguities as well, and are thus essentially useless for the delay estimation.
Keywords :
Additive noise; Bandwidth; Delay effects; Delay estimation; Estimation error; Frequency; Signal analysis; Signal resolution; Signal to noise ratio; Wideband;
fLanguage :
English
Journal_Title :
Acoustics, Speech and Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
0096-3518
Type :
jour
DOI :
10.1109/TASSP.1984.1164429
Filename :
1164429
Link To Document :
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