Radar detection of migrating targets using an interference correlation matrix
View Patent ↗A computer-implemented method is provided for detecting a target amidst clutter by a radar system able to transmit an electromagnetic signal, receive first and second echoes respectively from the target and the clutter, and process the echoes. The method includes determining signal convolution matrix for the target and a target return phase, clutter amplitude by spatial correlation matrix of clutter, clutter correlation matrix, receive noise power; querying whether the clutter moves as a motion condition if satisfied and as a stationary condition otherwise; calculating signal convolution matrix and target return phase from the signal convolution matrix and the target return phase for target motion; querying whether the target has range migration as a migration condition if satisfied and as a non-migration condition otherwise; and forming a target detector for the radar. The motion condition further includes calculating signal convolution matrix from clutter motion, clutter range migration matrix from the clutter motion, and interference correlation matrix. The stationary condition further includes calculating the interference correlation. The migration condition further includes calculating range migration matrix from the target motion.
1. A computer-implemented method for detecting a target amidst clutter by a radar system able to transmit an electromagnetic signal, receive from a radar antenna first and second echoes respectively from said target and said clutter, and process said echoes, said method comprising:
determining receive signal convolution matrix {tilde over (S)} for the target;
determining clutter amplitude by spatial correlation matrix of clutter R c ;
determining time correlation matrix ρ j,k ;
determining receive noise variance σ n 2 ;
querying whether the clutter moves as a motion condition when satisfied;
calculating interference correlation matrix R l from said receive signal convolution matrix, said time correlation matrix and said receive noise variance;
calculating doppler signal convolution matrix {tilde over (S)} d and target return phase change u i from said receive signal convolution matrix phase {tilde over (S)} for target motion;
querying whether the target has range migration as a migration condition for pulse m when satisfied; and
forming a target detector for the radar system based on threshold η, wherein
for said motion condition further including prior to said calculating interference correlation matrix:
calculating clutter signal convolution matrix {tilde over (S)} c (m) from clutter motion for said pulse m, and
calculating clutter range migration matrix {tilde over (R)} m (m) for said pulse in from said clutter motion, and
for said migration condition further including prior to said forming said target detector:
calculating target range migration matrix {tilde over (R)} m (m) from said target motion.
2. The method according to claim 1 , wherein the clutter is modeled by said spatial and time correlation matrices.
3. The method according to claim 1 , wherein forming a detector employs
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u
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H
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for said migration condition and
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where u i is pulse change for each 6 phase, h i is position and impulse response of the target, Y is a stacked vector, and H 0 and H 1 are lower and upper threshold values.
4. The method according to claim 1 , wherein said doppler signal convolution matrix is determined by:
S
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d
(
m
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=
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1
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2
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,
where s 1 are elements of the electromagnetic signal from the radar system.
5. The method according to claim 1 , wherein said target return phase change is determined by:
u
i
=
exp
(
j
4
π
R
(
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i
)
λ
)
,
where λ is the wavelength and T i is the pulse repetition interval.