1
Spectral identification Spectral identification & suppression & suppression
of ground clutter of ground clutter contributions for contributions for
phased array radarphased array radar
Spectral identification Spectral identification
of ground clutter of ground clutter
Svetlana Bachmann, Dusan Zrnic, and Chris Curtis
CIMMS, University of OklahomaNSSL/OAR/NOAA, Norman, Oklahoma
9A.49A.4
2
Each pixel on a radar display(one resolution
volume) is obtained from many samples.
For a large number of samples, a
Doppler spectrumDoppler spectrum can be estimated.
A Doppler spectrumDoppler spectrum is a distribution
of echoes (from one resolution volume)
in Doppler velocity.
Doppler velocity–va –½va 0 ½va va
Po
we
r, d
B
Ground clutter
Weather
Noise
Doppler SpectrumDoppler Spectrum
3
Doppler velocity–va –½va 0 ½va va
Po
we
r, d
B
Weather
Noise
Doppler SpectrumDoppler Spectrum
vv
vv
Ground clutter
4
Sample Time
Back in the Time DomainDoppler velocity
–va –½va 0 ½va va
Po
we
r, d
B
–½va 0 ½va
Po
we
r, d
B
–½va 0 ½va
Po
we
r, d
B
Phase-based clutter identificationPhase-based clutter identification
–½va 0 ½va
eo,
radi
ans
5
-30 -20 -10 0 10 20 30-60
-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=20 dB, v=2
-30 -20 -10 0 10 20 30-3
-2
-1
0
1
2
3
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-60
-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=20 dB, v=2
-30 -20 -10 0 10 20 30-3
-2
-1
0
1
2
3
Velocity, m s-1
even
-odd
pha
se,
rad.
100 simulations:
PRT = 0.8 ms, SNR = 20 dB, CSR = 40 dB, v = 2 m s–1, v = 10 m s–1
Pulse repetition time Signal to noise ratio Clutter to signal ratio Spectral width of weather
Velocity, m s–1
Po
we
r, d
B
eoeo, r
adia
ns
–½va 0 ½va
eo, r
adia
ns
SimulationsSimulations
Phase Phase eoeo
is close to 0 is close to 0 at Doppler binsat Doppler bins
with ground clutterwith ground clutter
eoeo is ais a
• spectral density of spectral density of phase coherencephase coherence
• diff. phase between diff. phase between spectral coefficient of spectral coefficient of even- and odd-indexed even- and odd-indexed time seriestime series
6
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1P
ower
, dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
Po
we
r, d
B
Doppler velocity, m s–1
eoe
o, r
adia
ns
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
-30 -20 -10 0 10 20 30-40
-20
0
20
40
60
80
Velocity, m s-1
Pow
er,
dB
PRT=0.8ms, CNR=60 dB, SNR=40 dB, v=2
-30 -20 -10 0 10 20 30
-2
0
2
Velocity, m s-1
even
-odd
pha
se,
rad.
Simulations -Simulations - zoom in zoom in100 simulations:
PRT = 0.8 ms, SNR = 40 dB, CSR = 40 dB, v = 2 m s–1
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
7
Velocity, m s-1
-10 0 10
10
20
30
40
50
60
70
80
90
100
Velocity, m s-1
PR
T=0.
8ms,
CN
R=4
0 dB
, SN
R=4
0 dB
,
v=2
-20 -10 0 10 20
10
20
30
40
50
60
70
80
90
100
-10 0 10 20 30 40 50
Velocity, m s-1
-20 -10 0 10 20
10
20
30
40
50
60
70
80
90
100
-10 0 10 20 30 40 50 -2 0 2
Simulations –Simulations – with & without clutter with & without clutterPRT = 0.8 ms, SNR = 40 dB, v = 2 m s–1, v = -5:5 m s–1
Sim
ula
tio
n
CSR = -40 dB CSR = 0dB
Velocity, m s-1
-10 0 10
10
20
30
40
50
60
70
80
90
100
Velocity, m s-1
PR
T=0.
8ms,
CN
R=0
dB
, SN
R=4
0 dB
,
v=2
-20 -10 0 10 20
10
20
30
40
50
60
70
80
90
100
-10 0 10 20 30 40 50
Velocity, m s-1
-20 -10 0 10 20
10
20
30
40
50
60
70
80
90
100
-10 0 10 20 30 40 50 -2 0 2
velocity, m s–1 velocity, m s–1
Original Notched
Velocity, m s-1
-10 0 10
10
20
30
40
50
60
70
80
90
100
Velocity, m s-1
PR
T=
0.8m
s, C
NR
=0
dB,
SN
R=
40 d
B,
v=2
-20 -10 0 10 20
10
20
30
40
50
60
70
80
90
100
-10 0 10 20 30 40 50
Velocity, m s-1
-20 -10 0 10 20
10
20
30
40
50
60
70
80
90
100
-10 0 10 20 30 40 50 -2 0 2
Velocity, m s–1 Velocity, m s–1
NotchedOriginal
Power, dB
8
Radar dataRadar data collected by Dave Priegnitz
Sept. 25, 2007, 13:49:59 UTC
-20 0 20
10
20
30
40
50
60
70
80
90
100
110
-10 0 10 20 30 40 50
-20 0 20
10
20
30
40
50
60
70
80
90
100
110
-10 0 10 20 30 40 50
-10 0 10
10
20
30
40
50
60
70
80
90
100
110
-2 0 2
velocity, m s–1 velocity, m s–1
Ran
ge,
km
Power,dB
9
July 26, 2007, 13:32:29 UTC
Radar dataRadar data
-10 0 10
10
20
30
40
50
60
70
80
90
100
110
-20 0 20
10
20
30
40
50
60
70
80
90
100
110
-10 0 10 20 30 40 50
-20 0 20
10
20
30
40
50
60
70
80
90
100
110
-10 0 10 20 30 40 50 -2 0 2
velocity, m s–1 velocity, m s–1
Ran
ge,
km
Power,dB
10
Spectral identificationSpectral identification & suppression & suppression
of ground clutterof ground clutter contributions for contributions for
phased array radarphased array radar
9A.49A.4
Phase-basedPhase-based
Thank you!Thank you! Questions?Questions?
11
Sept.25, 2007, 15:14:52 UTCJuly 30, 2007, 15:50:10 UTC Sept.19, 2007, 13:46:46 UTC
Power, dB
More examplesMore examples
12
OLDOLD NEWNEW
How does this technique compare to NEXRAD spectral GCF?
velocity, m s-1
-10 0 10
10
20
30
40
50
60
70
80
90
100
110
velocity, m s-1
-30 -20 -10 0 10 20 30
10
20
30
40
50
60
70
80
90
100
110
0 20 40 60 80
velocity, m s-1
-30 -20 -10 0 10 20 30
10
20
30
40
50
60
70
80
90
100
110
0 20 40 60 80
velocity, m s-1
-20 0 20
10
20
30
40
50
60
70
80
90
100
110
0 20 40 60 80 -2 0 2
velocity, m s-1
-10 0 10
10
20
30
40
50
60
70
80
90
100
110
velocity, m s-1
-30 -20 -10 0 10 20 30
10
20
30
40
50
60
70
80
90
100
110
0 20 40 60 80
velocity, m s-1
-30 -20 -10 0 10 20 30
10
20
30
40
50
60
70
80
90
100
110
0 20 40 60 80
velocity, m s-1
-20 0 20
10
20
30
40
50
60
70
80
90
100
110
0 20 40 60 80 -2 0 2
13
OLDOLDNEWNEW
Pgmap
, dB
Pdi
f.ph
ase,
dB
0 20 40 60 800
20
40
60
80
Pgm
ap,
dB
Po, dB
0 20 40 60 800
20
40
60
80
Pdi
f.ph
ase,
dBP
o, dB
0 20 40 60 800
20
40
60
80
How does this technique compare to NEXRAD spectral GCF?
14
NEWNEWOLD OLD
How does this technique compare to NEXRAD spectral GCF?
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