Dipartimento INFOCOM – Roma, 21 Ottobre 2008
Dottorato di ricerca in
Telerilevamento – XXII ciclo
Relazione dell’attività di ricerca
svolta durante il II anno
Carlo Bongioanni
Multichannel Passive Radar:
signal processing and
experimental prototype development
Tutor: Prof. Pierfrancesco Lombardo
Outline
Short summary of first year activity
PBR processing scheme
Wide-band prototypes development
INFOCOM acquisition campaigns
Experimental results validation: ATC data
Multi-Frequency detection schemes
Performance assessment of the Multi-Frequency approach
A new acquisition device: ICS-554B
Conclusions and future works
Publications and conferences
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
2
PBR Processing scheme
REFERENCE
CHANNEL
Ref
SURVEILLANCE
CHANNEL
DISTURBANCE
CANCELLATION
Surv
Surv’
Ref
2D CROSSCORRELATION
CFAR
THRESHOLD
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
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3
Time varying characteristics of the received FM radio signals
Instantaneous characteristics of the transmitted waveform
Both range resolution and sidelobe level depend on the
instantaneous transmitted waveform on the different FM
radio channels (program content)
REFERENCE
CHANNEL
SURVEILLANCE
CHANNEL
MULTIPATH
REMOVAL
DISTURBANCE
CANCELLATION
2D CROSSCORRELATION
CFAR
THRESHOLD
Instantaneous characteristics of the e.m. environment
The instantaneous characteristics of the FM channels
also depend on the presence/absence of multipath
effects (propagation)
Co- and inter- channel interferences can increase the
system noise floor thus reducing the achievable
detection performance
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
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4
Experimental results on the single FM channels
Temporal sequence of three plots on the same Range-Velocity map
93.8 MHz
89.8 MHz
-400
-400
-300
-300
15
15
410
-200
425
-100
361
331
392
100
429
316
200
315
20
40
60
80
100
120
Relative Bistatic Range [Km]
140
92.1 MHz
160
180
100
429
316
422
20
40
60
80
100
120
Relative Bistatic Range [Km]
413
425
-100
361
49
364
337
396
0
302
331
392
100
429
316
402
428
314
200
300
422
40
80
100
120
Relative Bistatic Range [Km]
361
140
160
180
200
297
364337
302
331
392
100
429
316
400
0
400
428
314
40
80
100
120
Relative Bistatic Range [Km]
361
140
160
180
200
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
297
364
337
396
0
302
331
392
100
429
316
400
0
428
314
315
287
300
10.05.42
10.06.05
10.06.29
60
425
200
422
196
413
-100
402
315
287
20
410
49
396
0
300
10.05.42
10.06.05
10.06.29
60
425
200
287
200
406
196
413
-100
402
315
410 -200
406
297
Bistatic Velocity [m/s]
49
180
15
-200
196
Bistatic Velocity [m/s]
410
160
-300
15
406
140
94.3 MHz
400
-300
20
10.05.42
10.06.05
10.06.29
-400
15
-200
315
287
-400
-300
428
314
91.3 MHz
400
-400
Bistatic Velocity [m/s]
302
400
0
200
364
337
331
392
300
10.05.42
10.06.05
10.06.29
297
396
0
200
422
400
0
361
402
287
300
425
-100
428
314
196
413
297
364
337
302
402
400
0
49
396
0
406
196
413
Bistatic Velocity [m/s]
Bistatic Velocity [m/s]
49
410
-200
406
422
20
40
10.05.42
10.06.05
10.06.29
60
80
100
120
Relative Bistatic Range [Km]
140
160
180
5
200
Multi-Frequency detection schemes (I)
zn,m n=0,..,N-1, m=0,..,M-1
R.V. z with pz(z) and Dz(z)
0
1
n
N-1
REFERENCE
CHANNEL
SURVEILLANCE
CHANNEL
xm=f(z0,m, z1,m, …, zN-1,m) m=0,..,M-1
R.V. x with px(x) and Dx(x)
Ref
DISTURBANCE
CANCELLATION
Surv
Surv’
Ref
2D CROSSCORRELATION
MULTI-FREQUENCY
INTEGRATION
CFAR
THRESHOLD
Doppler Shift
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6
Multi-Frequency detection schemes (II)
The availability of different FM radio channels can collect a huge amount
and a large diversity of information
Integration strategies
Decentralized (“L out of N” logic)
Centralized Linear:
xm =
∑z
zn,m n=0,..,N-1, m=0,..,M-1
R.V. z with pz(z) and Dz(z)
n
N −1
SUM
0
1
n, m
m = 0,.., M − 1
N-1
n =0
Centralized Non-Linear:
MAX
xm = max{z n, m }n = 0,.., N −1 m = 0,.., M − 1
MIN
xm = min {z n, m }n = 0,.., N −1 m = 0,.., M − 1
xm=f(z0,m, z1,m, …, zN-1,m) m=0,..,M-1
R.V. x with px(x) and Dx(x)
Slightly different integration times required
Noise floor normalization before integration
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
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7
Multi-Frequency detection schemes (III)
Theoretical Pfa expressions for the considered integration strategies:
CA-CFAR detection scheme
C
E
N
T
R
A
L
I
Z
E
D
N −1
SUM
MAX
P fa =
∑
n =0
M

 NM + n − 1




n

 G SUM −CA + M 
NM + n
 G SUM −CA 


M


N

iM
Pfa = ∑  N  ( −1) n +1  ∑  N  ( −1) i +1

n
i
nG MAX −CA + iM 
n =1  
 i =1  
N


M
Pfa = 

 GMIN −CA + M 
MIN
M
M
N
DECENTRALIZED
n
i
Pfa = ∑ N  PfaSC (1 − PfaSC ) N −i
i
i = L 
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
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PfaSC
M


=

 GSC −CA + M 
M
8
Multi-Frequency detection schemes (IV)
Theoretical Pfa expressions for the considered integration strategies:
GO-CFAR detection scheme
C
E
N
T
R
A
L
I
Z
E
D
SUM
M
Pfa =
∑
m =0
N −1 N −1
 M (− 1)m
m
∑
 
k0 =0
N
MAX
MIN
∑
k1 =0
N −1
L
∑
km −1 =0
Pfa = ∑  N  ( −1) n +1
n
n =1  
N
GSUM
(N − 1 + k0 + k1 + L + k m−1 )!
−GO
(N − 1)!k 0 !k1!Lk m−1! (GSUM −GO + m) N +k0 +k1 +L+km−1
NM
 ( −1) i +1
∑  NM
i 
nG MAX −GO + i
i
i =1
M
m
Pfa = ∑  M  ( −1) m+1
m
G MIN −GO + m
m=1 
N
DECENTRALIZED
i
Pfa = ∑ N  PfaSC (1 − PfaSC ) N −i
i
i = L 
M
PfaSC
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
m
= ∑  M  ( −1) m +1
m

GSC −GO + m
m =1 
9
Multi-Frequency detection schemes (V)
Theoretical Pfa expressions for the considered integration strategies:
SO-CFAR detection scheme
C
E
N
T
R
A
L
I
Z
E
D
SUM
MAX
N −1 N −1
P fa = 1 −
∑ ∑
N −1
L
k0 = 0 k1 =0
N M −1 N ( i +1)−1
Pfa = MN ∑
∑ ∑
k =1 i =0
l =0
1
 N   M − 1  N (i + 1) − 1 ( −1) k +i +l +1
 k  i  

l
 

kG MAX −SO + l

Pfa =
MIN
N
DECENTRALIZED
N
G SUM
( N − 1 + k 0 + k1 + L + k M −1 )!
− SO
N
(N − 1)! k 0 ! k1!L k M −1! (G SUM −GO + M ) −1+k0 +k1 +L+k M −1
k M −1 =0
∑
M
G MIN − SO + M
Pfa = ∑ N  PfaSC (1 − PfaSC ) N −i
i
i = L 
i
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
PfaSC =
M
G SC − SO + M
10
Wide-Band Prototypes development
Reference
Antenna
Dual channel
1st Nyquist
2nd Nyquist
A/D Converter
FM Band
Direct RF sampling
0
Fs/2
Surveillance
Antenna
Fs
(88
÷ 108 MHz)
External
Clock
Source
RF Amp.
IF Amp.
Down Conv
MIXER
RF
Low-pass
Dual channel
Filter
A/D Converter
IF
Signal down-conversion &
baseband sampling
LO
RF
IF
RF Amp.
Down Conv
IF Amp.
Low-pass
Filter
MIXER
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INFOCOM Acquisition campaigns
RX site: Riva di Traiano (Civitavecchia, ~70km north of Rome)
Reference antenna steered toward Monte Argentario (pointing north-west)
Surveillance antenna pointed at about 180° (standard arrival and departure
routes to and from Leonardo Da Vinci airport in Fiumicino)
Selection of a limited
number of FM radio
channels
300 data files covering
2 hours
Single acquisition
duration: about 1 sec
Temporal spacing
between acquisitions:
about 23 sec
Live ATC registrations
available
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12
Experimental results validation: ATC data
Example: 17 May 2007 acquisition
Single channel (93.8MHz)
Multi-Frequency integration:
89.8, 92.1, 93.8MHz (nominal Pfa = 10-4)
Comparison between detection results and live air traffic control
registrations
Performance evaluation for the implemented system: Pd e Pfa
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13
Performance assessment of the MF approach (I)
Extensive performance evaluation for the Multi-Frequency approaches
5 different MF configurations considered:
MFC2: 89.8 + 93.8 MHz
MFC3: 89.8 + 93.8 + 92.1 MHz
MFC4a: 89.8 + 93.8 + 92.1 + 91.3 MHz
MFC4b: 89.8 + 93.8 + 92.1 + 94.3 MHz
MFC5: 89.8 + 93.8 + 92.1 + 91.3 + 94.3 MHz
ΔR1: 5 ÷ 35 km
ΔR2: 35 ÷ 65 km
ΔR3: 65 ÷ 95 km
CA-CFAR and GO-CFAR: obtained False Alarm Rates are largely
comparable with the nominal Pfa value (10-3)
SO-CFAR: limited robustness when applied against real data
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Performance assessment of the MF approach (II)
1
0.9
0.9
0.8
0.8
0.7
0.7
0.6
0.6
Detection Rate
1
0.5
0.4
0.4
0.2
0.2
∆R1
∆R2
∆R3
0.1
0
0.5
0.3
0.3
SFC1
SFC2
SFC3
SFC4
SFC5
MFC2
MFC3
Single/Multi-Frequency Configurations
1
CA-CFAR
MFC4a
MFC4b
MFC5
∆R1
∆R2
∆R3
0.1
0
SFC1
SFC2
SFC3
SFC4
SFC5
MFC2
MFC3
Single/Multi-Frequency Configurations
∆R1
∆R2
∆R3
0.9
MFC4a
MFC4b
MFC5
GO-CFAR
0.8
0.7
Detection Rate
Detection Rate
Comparison between single frequency channels (SFC1-5) and the decentralized
integration strategies (Pfa = 10-3)
0.6
0.5
0.4
0.3
0.2
SO-CFAR
0.1
0
SFC1
SFC2
SFC3
SFC4
SFC5
MFC2
MFC3
Single/Multi-Frequency Configurations
MFC4a
MFC4b
MFC5
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Performance assessment of the MF approach (III)
False alarm rates obtained with the different centralized integration strategies in
conjunction with the different CFAR detection schemes (nominal Pfa = 10-3)
CA-CFAR and GO-CFAR: proper control of the Pfa with all the considered
integration schemes
SO-CFAR: false alarm rate comparable with the nominal one only in few
cases
MAX approach (both with CA and GO-CFAR) yields slightly higher false
alarm rates at short ranges: disturbance residuals in Range-Velocity map
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Performance assessment of the MF approach (IV)
Comparison among the different centralized integration strategies (Pfa = 10-3)
LINEAR
MAX
MIN
1
1
1
0.9
0.9
0.9
0.8
0.8
0.8
0.7
0.7
0.7
0.6
0.5
0.4
Detection Rate
Detection Rate
Detection Rate
CA-CFAR
∆R1
0.6
0.5
0.4
0.6
0.5
0.4
0.3
0.3
0.3
0.2
0.2
0.2
0.1
0.1
0.1
0
0
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
LINEAR
0
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
∆R2
∆R3
MAX
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
MIN
1
1
1
0.9
0.9
0.9
0.8
0.8
0.8
0.7
0.7
0.7
0.6
0.5
0.4
Detection Rate
Detection Rate
Detection Rate
GO-CFAR
∆R1
0.6
0.5
0.4
0.6
0.5
0.4
0.3
0.3
0.3
0.2
0.2
0.2
0.1
0.1
0.1
0
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
0
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
∆R2
∆R3
0
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
MIN approach always yields
worst performance
SUM (LINEAR) and MAX
integration strategies show
similar performance
SUM has slight advantage at
far range
MAX is slightly better than
SUM in detection
probability when using a
small number of integrated
channels
CA-CFAR seems preferable
with respect to GO-CFAR
(slight performance
improvement)
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
17
Performance assessment of the MF approach (V)
Detection performance comparison of the best performing integration
strategies using a CA-CFAR detection scheme (Pfa = 10-3)
∆R2
∆R3
1
0.9
0.9
0.9
0.8
0.8
0.8
0.7
0.7
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
SUM
MAX
DEC
SC2
SC1
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
Detection Rate
1
Detection Rate
Detection Rate
∆R1
1
0.6
0.5
0.4
0.3
0.2
0.1
0
SUM
MAX
DEC
SC2
SC1
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
SUM
MAX
DEC
SC2
SC3
0.6
0.5
0.4
0.3
0.2
0.1
0
MFC2 MFC3 MFC4aMFC4b MFC5
Multi-Frequency Configurations
Detection capability limited due to the long baseline between the TX and RX site
Proposed multi-frequency approaches yield a remarkable performance
improvement with respect to the best single-channels case for all the considered
surveillance regions
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
18
ICS-554B: main features
Technical Specifications:
ADC outputs are applied to a bank of 4
digital down-converter (DDC) modules
(Graychip GC4016 devices)
Each GC4016 device includes 4
independent DDC channels
4 analog input channels (4 ADCs)
ADC resolution: 14 bits
Input impedance: 50Ohm
Full scale input: 1.2 Vpk-pk (about 5.5dBm)
Input Signal Bandwidth: 2MHz ÷ 200MHz
Internal or external clock and trigger
Max. Sampling Rate: 100MHz for 4 channels,
simultaneous
Min. Sampling Rate: 30MHz for 4 channels,
simultaneous
Internal Sample Clock Oscillator: 100MHz
fixed frequency crystal
Spurious Free Dynamic Range (SFDR): > 85dB
Signal-to-Noise Ratio (SNR): > 71dB
User Programmable FPGA (1 million gates)
SMA coaxial connectors
Simultaneous down-conversion of up to 16 arbitrary signal bands (e.g. 16 FM
channels): onboard decimation, software selectable
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19
ICS-554B: block diagram
Several operation modes available
Examples of acquisition configurations:
2 antennas (2 ADC channels), 16 FM channels (8+8)
4 antennas (4 ADC channels), 16 FM channels (4+4+4+4)
…
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Relazione dell’attività di ricerca svolta durante il II anno
20
ICS-554B: GC4016 block diagrams
Each GC4016 device can be configured for 4, 2 or 1
output channel
Each DDCs can have independent frequency, phase
and gain controls
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21
Conclusions and future works (I)
The development of wideband experimental prototypes allowed us to
apply a multi-frequency approach which enhances the surveillance
capabilities of PBR.
The proposed approach yields improved performance w.r.t. the single
FM radio channels, since it makes the detection robust w.r.t. both the
content of transmitted radio broadcast channel and the channel
multipath conditions.
The performance improvement is paid in terms of computational load
In the specific considered case, a significant increase in the number of
integrated channels does not yield a further performance improvement
(poorer characteristics of additional channels).
Further improvement expected by adding good-performing channels
(when available).
Detection performance is still limited by interferences due to other FM
radio transmissions…
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
22
Conclusions and future works (II)
Different strategies can be considered to improve the detection
performance:
Automatic selection of the FM radio channels
Direct signal-to-Noise Ratio (DNR): this parameter allows to
identify high power transmissions and strongly affects theoretical
cancellation and detection performance
Reference to Surveillance Power Ratio (Front-to-Back ratio)
Program content
Interference rejection based on the exploitation of different polarizations
different FM radio channels transmitted with different
polarizations, even from the same transmitter: use of more than
two receiving channels
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
23
Conclusions and future works (III)
Different strategies can be considered to improve the detection
performance:
Antenna based interference rejection using multiple receiving channels
Direction of Arrival (DOA) estimation
example: one reference channel and two surveillance channels to
perform detection and DOA estimation based on phase differences
evaluation (monopulse)
DOA estimation with a multi-channel and multi-frequency
configuration
Track initiation
Multi-temporal analysis (used together with multi-frequency
approach)
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
24
Conclusions and future works (IV)
Exploitation of different opportunity waveforms: digital TV signals
Frequency range:
52 ÷ 88 and 174 ÷ 230 MHz
470 ÷ 870 MHz
VHF
UHF
Wider bandwidth: 7 ÷ 8 MHz
increased range resolution
High power transmissions
Wide coverage:
switch-off of analogical transmissions already started
Lazio: II semester of 2009
OFDM modulation
Presence of deterministic peaks
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25
Publications and conferences
A. Lauri, F. Colone, R. Cardinali, C. Bongioanni, P. Lombardo, “Analysis and emulation of FM
radio signals for passive radar”, 2007 IEEE Aerospace Conference, Big Sky (MT), USA, 3-10
March 2007
C. Bongioanni, F. Colone, S. Bernardini, L. Lelli, A. Stavolo, P. Lombardo, “Passive radar
prototypes for multifrequency target detection”, Signal Processing Symposium 2007,
Jachranka Village (Poland), 24-26 May 2007
F. Colone, P. Lombardo, C. Bongioanni, “Track initiation for FM-based passive radar using
multi-frequency and multi-temporal integration”, 5th Multi-National Passive Covert Radar
Conference, Shrivenham, Swindon (UK), 13-15 November 2007
P. Lombardo, F. Colone, C. Bongioanni, “Comparison of different approaches for a MultiFrequency FM Based Passive Bistatic Radar”, Sensors and Technology for Defence Against
Terrorism, Mannheim, Germany, 22-25 April 2008
P. Lombardo, F. Colone, C. Bongioanni, A. Lauri, T. Bucciarelli, “PBR activity at INFOCOM:
adaptive processing techniques and experimental results”, 2008 IEEE Radar Conference, Rome
(Italy), 26-30 May 2008
C. Bongioanni, F. Colone, P. Lombardo, “Performance Analysis of a Multi-Frequency FM
Based Passive Bistatic Radar ”, 2008 IEEE Radar Conference, Rome (Italy), 26-30 May 2008
(Best student paper award)
F. Colone, C. Bongioanni, P. Lombardo, “Multi-Frequency target detection in FM Radio Based
Passive Bistatic Radar”, IEEE Transactions on Aerospace and Electronic Systems (attualmente
in revisione)
Carlo Bongioanni – Dottorato di ricerca in Telerilevamento (XXII ciclo)
Relazione dell’attività di ricerca svolta durante il II anno
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