This document describes a VHF software radar system developed using an existing P-18 antenna platform. The system's goals were to experimentally detect low-altitude, low radar cross section air targets. Key features included a sub-impulse modulated transmitter, pulse compressed receiver, and digital signal processing for functions like pulse compression, integration, and moving target indication. The system was tested in field trials through NATO programs, demonstrating its capability to successfully operate and generate radar plots using the P-18 antenna system.

1. VHF software radar
based on P-18 antenna system
Dr. Bertalan Eged*, Benjamin Babják**
*Sagax Communications, Ltd.
Haller u. 11-13. Budapest 1096 Hungary
**Budapest University of Technology and Economics,
1111 Budapest Goldmann Gy. t ér 3.
www.sagax.hu
www.sagax.hu

2. Content
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•
•
•
•
The goals of the project
Technological goals
Implementation technology
System configuration
User interfaces
– PP indicator
– Control panel
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•
Output signal description
Typical signal processing samples
– Pulse compression
– Integration
– DMTI
•
Field trial
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3. The goals of the project
• Experimental search radar equipment for air targets:
–
–
–
low-cross section
low-heigth
unexpectedly occur
• Experimental test system
for measurements
• Using existing antenna
system and platform of P-18
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4. Technological goals
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•
•
•
•
Sub-impulse modulated transmitter
Pulse compressed receiver
Semiconductor based
Computer controllable
System integration ready
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5. Radio electronic equipment
Traditional implementation
RF
IF Down
Conversion
IF
Baseband
Down
Conversion
BB
Baseband
Demodulation
and
Processing
Implementation based on Software Defind Radio
Technology
Analog
front-end
RF
technology
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Domain
conversion
A/D és D/A
Conversion
technology
Digital
processing
DSP
technology
MMI/GUI
technology
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6. Implementation levels
Digital
signal
handling
Digital
BB
Digital
IF
Digital
RF
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7. System configuration
3X400V
or
3X220V
Power supply
distributor
P-18
antenna
platform
230V
Antenna connection
Syncronization
interface
Antenna
control
RF
front-end
Antenna position Signal and data Plots
processing
RS-232
RS-232
IP
PPI
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8. Experimental transceiver
Power
Amplifyer
Antenna
T/R
switch
RX
down
converter
Control and power supply
Hardver platform
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DAC
Sub-impulse
modulated
pulse generator
ADC
Pulse
compression
receiver
Reference
oscillator
Low-noise
Amplifyer
Antenna
position
TX
up
converter
Operating
and application
programs
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9. Digital signal processing
Staying
targets
Digitized
IF signal
Digitized Band limited
BB signal integrated
signal
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Compressed
pulses
Moving
targets
CFAR
level
Shots
Targets
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10. Sub-impulse modulation
64us radiated pulse
1us compressed received pulse
80
Impulse Compression
1
Channel
0 .5
0
-0 . 5
-1
0
0 .5
Time
1
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20
0
-20
0
1 .5
x 1 0 -3
Sub-impuls
modulated search signal
DSP
technolgy
60
0 .5
Time
1
1 .5
x 1 0 -3
Matched-filter
pulse compressor
1MHz bandwidth
DSP
technology
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11. Compression gain
Receiver IF output:
signal+noise
Output of the matched filter:
SNR improoved
40
21
20
30
signal
19
20
18
17
10
16
0
15
14
0
0.2
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0.4
0.6
time
0.8
1
1.2
-3
x 10
-10
0
0.2
0.4
0.6
time
0.8
1
1.2
-3
x 10
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12. Hardware implementation
PA Power supply
PA
Isolation transformer
Platform
computer
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LNA
Low-level
RF connections
Booster
T/R switch
IF and trigger
connections
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13. Solid-state power amplifier
4X 800W
3200W
4X 200W
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14. Output power measurement
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15. Menu
PP indicator
Icons
Display area
Control area
Status
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16. Control panel
Control
area
A-type
indicator
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17. Automatic trigger changing
320 Hz
500 Hz
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18. Output frequencies
153
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155
157
159
161
163
165
167
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19. Pulse compression: Barker
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20. Pulse compression: MLS
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21. Pulse compression: LFM
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22. Pulse compression: P2
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23. Digital signal processing: CINT=1
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24. Digital signal processing: CINT=10
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25. Digital signal processing: VINT=1
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26. Digital signal processing: VINT=10
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27. Digital signal processing: DMTI
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28. Digital signal processing: DMTI off
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29. Digital signal processing: DMTI on
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30. Results: compressed pulses
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31. Results: moving targets
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32. Results: decision hits
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33. Results: target search
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34. Results: plot generation
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35. Field trials
• NATO RTO SET-078 TG-046
“Multi-Band Radar For Air Defense Systems”
• COSIMA I Trial:
– 2004 October, Medina, Hungary
• COSIMA II Trial:
– 2005 September, Livorno, Italy
*Co-located Simultaneous Multi-band-radar Analysis
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36. COSIMA II site in Italy
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37. COSIMA II deployed radars
MEPHIS (DE)
[10/35/94GHz]
DIMURA (NO) MELISSA (DE)
[5.9GHz]
[238-348MHz]
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MMS-300 (IT)
[2-18GHz]
SRV-P18 (HU) SzT-68UM (HU)
[150-170MHz] [2.8-3.1GHz]
150MHz-94GHz
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38. COSIMA II targets and trajectories
Piper:
Cesna 172
Jet
KingAir 200
Ship
Rosetti
Helikopter
B200
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39. COSIMA II measured plots vs GPS
km
SRV-P18
plots
GPS tracks
km
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40. COSIMA II: SRV-P18 Toszeg vs. C1
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41. Conclusions
• A complete software based radar system
– Digital signal and data processing
– VHF analog front-end with
3KWp solid-state power amplifier
– Interfacing to the existing P-18 antenna system
• Error-free operation during the field trials
• Capability of available technology and
knowledge base in Hungary was
demonstrated
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