JED - August 2014 - 30

The Journal of Electronic Defense | August 2014


"They may not provide the same quality
as a full rack-mount, purpose-built receiver but they're good enough to process
most of what is out there."
Even so, more powerful and sophisticated signal processing capability is
becoming increasingly important as
the complexity of modems dramatically increase, and with higher-order
modulation schemes, like Orthogonal
Frequency-Division Multiplexing (OFDM)
and Quadrature Amplitude Modulation
(QAM), becoming common in HF. Kilgallen points out that these higher-order
modulation schemes are not just the
province of modern military systems,
but in fact are readily available commercially. "Anybody can write software,
upload it to firmware. Boom, you've got
a new capability."
Jim Taber, Director of Sales and Marketing for X-COM Systems (Reston, VA)
agrees noting that "before you can address the threat, you must know it exists, and many IQ collection systems are
either too narrow-band or too low signal
fidelity or don't have 100 percent probability of intercept. Unfortunately, modern threats are pushing the performance
boundaries on all three dimensions."
X-COM makes broadband RF record
and analysis systems ranging from a
few MHz of IQ band to 6000 MHz bandwidth of continuous uninterrupted recording for many minutes. The data can
then be offloaded to a workstation or
PC, for more detailed fingerprinting and
analysis using the company's "SPECTROX" tool.
Taber says they see their role as helping, not the warfighter directly, but the
designer of the tool for the warfighter to
understand what the threats are. "The
value we provide the COMINT guys is in
our ability to take inventory of all emissions in the HF, VHF and UHF bands no
matter how elusive they might be." For
COMINT, X-COM is focusing their attention primarily on narrowband systems
where they see the greater requirement.
"Some of our wideband stuff is relevant
for COMINT, but not many customers require that much bandwidth. The value
of narrowband is that you're buying a
recorder that is an incremental expense
over what you already have in your lab.
Everyone has spectrum analyzers, gen-

Rather than HF going
away, Kilgallen says
that what actually
happened is that the
SIGINT community
just largely decided to
look away, focusing
on other parts of the
spectrum instead.
erators. Now you have a recording piece
that is very high fidelity."
Ultimately, Kilgallen says that, "At
the brute level, the wideband systems
need to advance in terms of their ability to classify the environment, because
they're blind to a lot of it right now."
But he adds that with some of the new
technology now being developed and
deployed, systems may soon be able to
operate at speeds where the distinction
between narrowband and wideband collection becomes moot. "You're essentially collecting and cataloging so fast,
you can drop everything to a collection
channel where the user can pick and
choose what they want to look at further, and determine how to react to it
- jam, destroy, listen etc."

The process of fully classifying a signals environment can involve sweeping
through an enormous part of the spectrum and identifying perhaps a million
different signals. By defining a specific subset of signals and modulation
types of interest, this may be reduced
to around 10,000. As Kilgallen explains,
however, while this "is a start, and it's
useful, it's also useless at the same time
because the analyst still has way more
than they can deal with in that moment.
What's needed are wideband systems
that work as well as they do now with
collection but that can also do a better job of classifying the environment."
Kilgallen says the problem remains that
the systems are hamstrung by the limits

of modulation recognition technology
- "which is the first level of classification, and if you ask users in the civilian intelligence community or military
if they need more and better tools, they
will all give you an unequivocal 'yes.'"
X-COM's Taber says, "Big IQ data collection is only the first step. Once users have collected their mountain of
data, they need to know how to sort
it to locate their signals of interest.
Perhaps more to the point is that they
need to find their needle in a mountain of needles."
Wollesen says a big part of the solution may be found in open-source,
commercial software that wouldn't
necessarily jump out as applicable to
the problem. For example, he points to
commercial "SHAZAM" mobile device
application software that automatically
recognizes music and TV by creating a
digital fingerprint of the audio within
seconds and matching it to a database of
millions of tracks and TV shows.
Wollesen observes that there's no
reason why the same principles can't be
applied to the RF SIGINT task. "There
are a lot of parallels, and it would allow
far better signal and signature libraries
to be built, and, because it's softwaredefined, you can really decouple the raw
sensor input from the processing." In
addition, Wollesen notes that because
you can record the data, "analysts would
no longer be stuck in the analog domain
with real-time scopes where transient
signals are lost. Here you actually have
the ability to correct your mistakes."

One additional, and perhaps the most
important element, of the HF SIGINT
system design equation is finding ways
to better correlate the requirements
and desires of the collection system
users with the capabilities and interfaces being provided to them by system designers. Although all, or at least
most of the technical parameter data
collected and processed by HF SIGINT
systems is needed to allow them to fully and efficiently identify and categorize signals and modulation types, this
level of technical detail is not needed
by the users themselves, at least not
those in the field. In fact, it serves to


JED - August 2014

Table of Contents for the Digital Edition of JED - August 2014

The View From Here
Conferences Calendar
Courses Calendar
From the President
The Monitor
Washington Report
World Report
Back to the Future With HF SIGIHT
HF SIGIHT Battles the Ionosphere
Technology Survey: Solid-State Power Amplifiers
Book Reviews
EW 101
Index of Advertisers
JED Quick Look
JED - August 2014 - cover1
JED - August 2014 - cover2
JED - August 2014 - 3
JED - August 2014 - 4
JED - August 2014 - 5
JED - August 2014 - The View From Here
JED - August 2014 - 7
JED - August 2014 - Conferences Calendar
JED - August 2014 - 9
JED - August 2014 - Courses Calendar
JED - August 2014 - 11
JED - August 2014 - From the President
JED - August 2014 - 13
JED - August 2014 - Letters
JED - August 2014 - The Monitor
JED - August 2014 - 16
JED - August 2014 - 17
JED - August 2014 - 18
JED - August 2014 - 19
JED - August 2014 - 20
JED - August 2014 - 21
JED - August 2014 - Washington Report
JED - August 2014 - 23
JED - August 2014 - World Report
JED - August 2014 - 25
JED - August 2014 - 26
JED - August 2014 - 27
JED - August 2014 - Back to the Future With HF SIGIHT
JED - August 2014 - 29
JED - August 2014 - 30
JED - August 2014 - 31
JED - August 2014 - HF SIGIHT Battles the Ionosphere
JED - August 2014 - 33
JED - August 2014 - 34
JED - August 2014 - 35
JED - August 2014 - 36
JED - August 2014 - Technology Survey: Solid-State Power Amplifiers
JED - August 2014 - 38
JED - August 2014 - 39
JED - August 2014 - 40
JED - August 2014 - 41
JED - August 2014 - 42
JED - August 2014 - 43
JED - August 2014 - 44
JED - August 2014 - Book Reviews
JED - August 2014 - EW 101
JED - August 2014 - 47
JED - August 2014 - 48
JED - August 2014 - Index of Advertisers
JED - August 2014 - JED Quick Look
JED - August 2014 - cover3
JED - August 2014 - cover4