US 5,394,155 AGranted

Apparatus and method for estimating weather spectral moments

AssigneeUnisys Corporation

InventorsWilliam L. Rubin, John W. Davidsen

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Abstract

A spectral moment estimator includes a first processor which processes signals representative of the magnitudes of complex autocorrelation functions of a signal at a plurality lags and provides Doppler spectral width representative signals and the autocorrelation function at zero lag independent of noise. A second processor, processes the complex autocorrelation representative signals, the complex autocorrelation functions phase angles representative signals, and the Doppler spectral width representative signals to provide the mean Doppler frequency of the the signal. The autocorrelation function phase angles are disambiguated and the unambiguous phase angles are least mean square error fitted to a third order odd polynomial, the linear term of which is the mean Doppler frequency of the signal.

Claims11

Dependent claims

An apparatus for estimating spectral moments of a received radar signal comprising:

an autocorrelator having input means for receiving signals representative of the received radar signal, said autocorrelator providing signals representative of complex autocorrelation function values for said received radar signal, signals representative of phase angles of said complex autocorrelation function values, and signals representative of magnitudes of said complex autocorrelation function values;
first processor means coupled to receive said signals representative of magnitudes of said autocorrelation function values for providing signals representative of autocorrelation function values at lag zero with noise components removed therefrom and signals representative of Doppler frequency shift spectral width of said received signals;
and
second processor means coupled to receive said signals representative of said complex autocorrelation function values, said signals representative of said phase angles, and said signals representative of said Doppler frequency shift spectral width of said received signals for providing a signal representative of mean Doppler frequency shift of said received radar signal.

1 more element

A method for estimating spectral moments of a received radar signal having an interpulse interval T comprising the steps of:

autocorrelating said received radar signal at a plurality of lag numbers to obtain signals representative of complex autocorrelation function values at a plurality of said lag numbers;
determining magnitudes and phase angles of said complex autocorrelation values and providing magnitude and phase angle representative signals;
processing said magnitude representative signals to obtain a signal representative of an autocorrelation function value at lag zero with noise components removed therefrom and to obtain a signal representative of Doppler frequency spectral width;
converting said Doppler frequency spectral width representative signal to a signal representative of an autocorrelation function width;
and
obtaining a signal representative of mean Doppler frequency of said received radar signal from said complex autocorrelation function values representative signals, said phase angles representative signals and said autocorrelation function width representative signal.

3 more elements

Dependencies are inferred from the claim text.