9. HOW TO SPEAK EW
• OLD EW
TERMINOLOGY
– ECM (Electronic
Counter-measurements).
– ECCM ( Electronic
Counter-Counter-
Measurements).
– ESM (Electronic
Support-measurements).
• NEW EW
TERMINOLOGY
– EP (Electronic
Protection).
– EA (Electronic Attack).
– ES (Electronic Support).
10. RF Electromagnetic Spectrum
• ELF Extremely Low Frequency 3 - 30 Hz 100,000 - 10,000 km
• SLF Super Low Frequency 30 - 300 Hz 10,000 - 1,000 km
• ULF Ultra Low Frequency 300 - 3000 Hz 1,000 - 100 km
• VLF Very Low Frequency 3 - 30 kHz 100 - 10 km
• LF Low Frequency 30 - 300 kHz 10 - 1 km
• MF Medium Frequency 300 - 3000 kHz 1 km - 100 m
• HF High Frequency 3 - 30 MHz 100 - 10 m
• VHF Very High Frequency 30 - 300 MHz 10 - 1 m
• UHF Ultra High Frequency 300 - 3000 MHz 1 m - 10 cm
• SHF Super High Frequency 3 - 30 GHz 10 - 1 cm
• EHF Extremely High Frequency 30 - 300 GHz 1 cm - 1 mm
12. EW Frequency Band Designations
A 30 - 250 MHz
B 250 - 500 MHz
C 500 - 1,000 MHz
D 1 - 2 GHz
E 2 - 3 GHz
F 3 - 4 GHz
G 4 - 6 GHz
H 6 - 8 GHz
I 8 - 10 GHz
J 10 - 20 GHz
K 20 - 40 GHz
L 40 - 60 GHz
M 60 - 100 GHz
16. TECHNICAL ELINT COLLECTION
• HIGH PRIORITY:
– Threat signal.
– New signals.
• METHOD:
– Position collector to make intercept.
– Insure that collector has measurement capability.
– Record target and calibration-test signals.
• COLLECTORS:
– Antenna,
– receiver,
– recorders,
– analyzers;
– special configurations vs. generic;
– platform choice;
– environment.
20. BAND WIDTHS
• Frequency Coverage Bandwidth
– Total RF Bandwidth
• Instantaneous Bandwidths
– RF Bandwidth
– Noise Floor RF Bandwidth
– IF Bandwidth
– Video (Post Detection) Bandwidth
– Noise Bandwidth
21. CHOOSING RECEIVERS
• Application is Important
– What information do you need?
– What are you going to do with the information?
• Radar warning receiver/ESM
• Technical ELINT
• Operational ELINT
• Specific identification (SEI)
• Density
– Where will you operate?
– What sensitivity is required?
• Types of Signals
90. ELINT Processing - I
• Today’s systems rely on processing each
received radar pulse (PDW). Measurements
typically include Pulse width, RF, Time of Arrival
(TOA), and Angle of Arrival (AOA).
• Pulses are sorted into “clusters” believed to
have come from the same transmitter by
matching PW, RF, AOA
– note RF is not constant for Frequency Agile signals.
These require added processing.
91. ELINT Processing – II
• Based on the clustering results, pulses are
placed into pulse trains if they have
“sensible” TOA sequences
• Then PRI parameters are determined
– PRI value
– PRI Jitter values
– Stagger sequence and period or “stable sum”
92. ELINT Processing – III
• If threats operate with other related
transmissions, the narrow band receiver may
look for the associated signals
• If pulses have the same PW and AOA but
differing RFs, one may conclude that it is a
frequency agile threat
• AOA is normally a fixed value over many pulses
even for moving threats. DF and Geo processing
can be performed on the threat.
93. ELINT Processing – IV
• The ID tables used in ESM systems are
built using the results of Electronic
Intelligence (ELINT) efforts over long
periods of time
• The ESM user customizes the world wide
threat data to his region of operations
Non-threatening signals must be handled,
too (Own-ship blanking)
94. ELINT Processing – V
• Threat Identification is done by measuring
signal parameters and using table look up
• ID Table data (initially) comes from
Intelligence holdings
• Parameter variations and mimicking other
signals are ways to degrade ID
• Generic Threat ID is a possibility
96. Future ELINT Threats – I
LPI Emitters
• New types of emitters that spreads their
power over time, instead of sending
instantaneous high power.
• Difficult to detect by traditional EW assets.
• Needs need EW assets, and CONOPS
that will dwell on a receiver and integrate
its power over time.
• Frequency agiles are not LPI in terms of
this power definition.
97. Future ELINT Threats – II
Frequency Hopping Emitters
• Frequency Hoppers are emitters that
switches their carrier frequency over a
wide band of frequencies to avoid
exploitation and/or detection.
• Hoppers are a feature of modern
communications hardware, and soon to be
a common feature of radar assets, with
the advanced is digital processing and
DSP techniques.
98. Future ELINT Threats – III
Spread Spectrum Emitters
• Other Future hopper-like radar systems could be
called “Spread Spectrum” if they coherently
combine the echoes in several range cells prior
to making target detection decisions
• Coherently combining the echoes means
adjusting the phase of the echoes in adjacent
range cells prior to adding them together.
• This requires more signal processing and cost,
but could happen
