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Abstract.
Electronic warfare (EW) is commonly, and often deliberately, shrouded in
complexity and secrecy. It is therefore probably not surprising that
there are few top-level, comprehensible descriptions of the field that
are accessible to the uninitiated. EW 101: A First Course
in Electronic Warfare is one of the few books available
that is targeted at non-experts and is intended to be
easy to read without glossing over important technical details.
The
book is based on Dave Adamy’s popular series of articles
published in the Journal of Electronic Defense (JED) since October
1994 (for those interested in traceability, Appendix A maps the
JED articles into the book chapters). Dave holds BSEE and
MSEE degrees in communication theory and is very active in
EW-related fields having been an EW professional in and out
of uniform for almost 40 years. In addition to the
EW 101 columns, he has published seven books. He provides
EW-related courses around the world and is a regular consultant
to defense and defense industry.
Chapter 1 provides an introduction to
the field and introduces a simple taxonomy for the field
of EW. While the chapter makes the distinction between communications
and non-communications EW, the majority of the book is about
non-communications EW. Although some general references are given at the
end of the introductory chapter and others are provided throughout
the text, more-detailed references at the end of each chapter
would have enhanced the book’s position as an ideal jumping-off
point for those interested in learning more about EW. Additionally,
although the taxonomy of EW is introduced in Chapter 1,
a novice would appreciate the author placing the techniques discussed
in each chapter within the accepted framework of electronic support,
electronic attack, and electronic protection.
While the reader des not get
drawn into complex mathematics in EW 101, some understanding of
algebra and trigonometry is required. Chapter 2 covers the basic
mathematics (decibels, and spherical trigonometry) that underpin the EW concepts
introduced in later chapters. In addition, basic propagation is discussed
and elementary link equations are presented. Adamy’s premize is, quite
rightly, that a good understanding of propagation is key to
understanding EW principles.
Chapters 3 to 9 cover the various major
aspects of EW. Chapter 3 covers some definitions, the parameters
and common applications of various EW antennas as a guide
to the use of antennas in EW roles. Some simple
formulas are presented to enable the trade-off of various antenna
parameters within different applications.
Chapter 4 describes EW receivers and their
various roles. Simple explanations are given of the operation of
crystal video, instantaneous frequency measurement (IFM, tuned radio frequency (TRF),
superheterodyne, fixed-tuned, channelized, Bragg cell, compressive, and digital receivers. The
chapter also examines the calculation of receiver sensitivity for various
types of receivers and describes systems in which multiple receivers
are used for a single application.
EW processing is discussed in
Chapter 5. Processing tasks are described within the categories of
threat identification, signal association, emitter identification, emitter location, sensor control,
countermeasure control, sensor cueing, man-machine interface, data fusion. Discussion focuses
on non-communications processing applications.
Chapter 6 discusses EW search techniques
through which the presence of threat signals are detected. Parameters
such as probability of intercept (POI) are defined and search
trade-offs, types of search receiver, and search strategies are described.
Search for communications receivers is briefly described before discussion centres
on radar signal search.
Low probability of intercept (LPI) signals
are covered in Chapter 7, which describes techniques such as
emission control, narrow antenna beam, low effective radiated power, and
spreading modulation such as direct sequence spread spectrum modulation.
Some common
emitter-location techniques are covered in Chapter 8. Emitter location, also
commonly called direction finding, is a key element of EW
and this chapter discusses the objectives of obtaining an electronic
order of battle of an adversary, weapon sensor location, enemy
asset location, precision target location, and emitter differentiation. Details of
emitter location geometry are provided and location accuracy and calibration
issues are presented. The major direction finding techniques are also
described.
Chapter 9 covers jamming (electronic attack) and describes a number
of types of jamming: communications jamming, radar jamming, cover jamming,
deceptive jamming and decoy. Although this framework is suitable from
a non-communications perspective, is too simplistic for communications EW (for
example, deceptive jamming is also used for communications). Jamming-to-signal ratio,
burn-through, power management and look-through are also discussed.
Chapter 10 covers
active and passive radar decoys, providing appropriate calculations. Chapter 11
covers the role of simulation in evaluation, training and testing
of EW systems.
EW 101 is an essential addition to the
library of the EW professional, whether technical or not. While
it provides an excellent introduction to electronic warfare in general
and non-communications EW in particular, some minor aspects of the
book will be mildly dissatisfying to readers seeking to understand
communications EW. This is in common, however, with most books
on EW that tend to focus on either non-communications or
communications EW, and rarely both to the same depth. EW
101 is, as it sets out to be, easy to
read and succeeds in explaining a relatively complex field in
simple terms.
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