Transcript Improved Effectiveness Through DRFM

MC Countermeasure Inc.
Improved Effectiveness Through
DRFM-Based ECM Timesharing
By
Scott McDonald & Ken McRitchie
Ottawa, Ontario, Canada
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Overview
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AOC February 2004
Introduction
DRFM Issues
Timeshare basics
Results
Summary
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Introduction
•Discussion limited to DRFM-based ECM
– generally “single threat” device
•Typical radar environments are complex
– Many emitters
– Scanning/non-scanning
•IR&D application of PRI Prediction that leads
to ability to timeshare a single DRFM among
multiple radars
AOC February 2004
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3
Single Emitter
Pulse Train #1
ECM Output
Down-Range Up-Range
AOC February 2004
Down-Range Up-Range
Down-Range Up-Range
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Down-Range
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A Problem – Interleaved
PRI Patterns
Pulse Train #1
Pulse Train #2
ECM Output
Pulse Train # 1 Pulse Train # 2 Pulse Train # 1
AOC February 2004
Pulse Train # 2
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Pulse Train # 1
Pulse Trai
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Second Problem Situation
• Weapon Systems that use separate
Acquisition and Track radars
– (Generally) not good enough jamming just the
tracker
AOC February 2004
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6
Timeshare Architecture
Composite Video
& RF Words
RF
Channel
Select #1
PRED
Channel
#1
Composite Video
& RF Words
RF
Channel
Select #2
PRED
Channel
#2
Composite Video
& RF Words
RF
Channel
Select #3
PRED
Channel
#3
Composite Video
& RF Words
RF
Channel
Select #4
PRED
Channel
#4
AOC February 2004
DRFM
Strobes #1
DRFM
Strobes #2
DRFM
Strobes #3
Time
Share
Selection
Logic
DRFM_W
&
DRFM_R
DRFM
Strobes #4
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Advantages of Predictive
Approach
• Allows up-range false targets despite the
(radar’s) use of PRI agility.
• Helps resolve complications caused by
pulse overlaps and missing pulses
• Improved performance vs scanning radar
– fast reacquisition – typically only a few PRI
– increased ECM effectiveness.
• Allows exclusion of other emitters
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Basic Algorithm
• Highest priority assigned to Ch #1
• Lowest priority assigned to Ch #4
• First-come-first-served (with caveats)
– Scanning emitters interrupt jamming of any
non-scanner
– Time co-incident detection settled by channel
priority
AOC February 2004
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4 el - 4 pos
@220 us
10 us PW
0.5 s illum
2.8 s scan
4el-16pos
@ 661 us
1 us PW
0.04s illum
0.75 s scan
AOC February 2004
5el - 25pos
@ 48 us
8 us PW
0.054s illum
0.45s scan
constant
@ 36.5 us
2.6 us PW
0.017S illum
0.33 scan
PRED
DRFM
Control
signals
constant
@ 6.3 us
1.7 us PW
0.054s illum
1.3 s scan
costant
@ 23 us
2 us PW
0.058s illum
0.48s scan
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Signal Generation
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11
% Corre ct
Fals e Tgts
Timeshare Results
100
80
60
40
20
0
#1
#2
#3
#4
#5
#6
Radar
no RF f ilt er
AOC February 2004
single t rack
indep ch's
Timeshare ch's
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env=5sc +1ns
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% Corre ct
Fals e Tgts
Timeshare Results
100
80
60
40
20
0
#1
#2
#3
#4
#5
#6
Radar
no RF f ilt er
AOC February 2004
single t rack
indep ch's
Timeshare ch's
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env=5sc +1ns
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Timeshare Results
% Correct
False Tgts
100
no RF filter
single track
80
indep ch's
60
Timeshare ch's
env=5sc +1ns
40
20
0
#1
#2
#3
#4
#5
#6
Radar
AOC February 2004
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% Corre ct
Fals e Tgts
Timeshare Results
100
80
60
40
20
0
#1
#2
#3
#4
#5
#6
Radar
no RF f ilt er
AOC February 2004
single t rack
indep ch's
Timeshare ch's
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env=5sc +1ns
15
% Corre ct
Fals e Tgts
Timeshare Results
100
80
60
40
20
0
#1
#2
#3
#4
#5
#6
Radar
no RF f ilt er
AOC February 2004
single t rack
indep ch's
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Timeshare ch's
env=5sc +1ns
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Summary
• PRI prediction channels can be used to
selectively track or ignore specific emitters.
• PRI prediction reduces the effects of
overlapping or missing pulses.
• Timesharing can be used effectively to jam
multiple radars with a single ECM asset.
• Timesharing results in cost savings.
AOC February 2004
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17
Acknowledgement
The authors would like to acknowledge the
contributions of the other members of the
MC Countermeasures team including:
• Dan Grise
• Remi Gauvin
• Colin Jackson
AOC February 2004
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Questions
For further information, please feel free to contact us at:
MC Countermeasures Inc.
39 Robertson Road, Suite 256
Nepean, Ontario, K2H 8R2 Canada
Tel: +1 (613) 721-1552
Fax: +1 (613) 721-1553
http://www.mc-cm.com
[email protected]
[email protected]