Introduction to Electronic Defense Systems, Second Edition (Artech House Radar Library)

646 Pages·2006·20.55 MB·English

by  Filippo Neri

Introduction to Electronic Defense Systems
Second Edition
Filippo Neri
.
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Foreword
In my government position I am responsible for military research and tech-
nology for the Italian armed forces. During my coordination work with the
Western European Armament Group: Panel I1 (Research and Technology),
discussions have often been of a highly technical nature. It is certainly eas-
ier to make management decisions with an adequate technical background,
rather than having to grope with a poor knowledge of such technical issues.
As a result, I support any effort that has the objective of promoting an under-
standing of the many facets of military technology within the international
community of people in charge of armament matters.
Therefore, I greatly welcome Filippo Neri's easy and straightforward
explanations on the most recent developments in the electronic defense field,
from stealth technology to decoys, from electronic support measures (ESM)
to advanced jamming techniques. In particular, the principles underlying
low probability of intercept (LPI) threats, passive location techniques, the
benefits afforded by advanced digital receivers, towed decoy jammers, new
cross-eye jamming self-protection techniques, and high-power microwave
weapons, have been illustrated in very simple terms.
This book illustrates the significant progress that electronic defense
technology has made and is expected to achieve in the future with the advent
of advanced integrated systems (e.g., multifunction W systems and direct
energy weapons). The latter will not only represent effective aids to military
operations, but also act as a deterrent to any likely conflicts. Moreover, the
book describes how modern electronic defense systems operate and how they
can be put to use in the military operations of today and tomorrow.
xvi Introduction to Electronic Defense Systems
Since this book has been revised and updated to account for the new
advances in electronic defense techniques and technologies, I am certain that
this second edition will be as popular as the first, which has been selected as
a basic EW textbook by many military colleges both in Europe and in the
United States. As an Italian officer, I must confess to be proud of it.
I hope that the insight gained from reading this book will help defense
personnel to better define their requirements and prompt the defense indus-
tries towards the development of high-performance, cost-effective, and
affordable systems.
Now that EW has proven to be a real deterrent and force-multiplier, I
hope that armed forces around the globe will realize the benefits that new
technological developments can afford and that these new assets will con-
vince decision-makers to abstain from undertaking sad wars based on hard-
kill weapons and to pursue less destructive and more effective solutions
in order to arrive at no-casualty operations based on high-tech electronic
defense in support of political activities.
Major General Pietro Finocchio
Italian Air Force
August 2001
In my work as a designer of electronic defense equipment, I have often real-
ized that there is no book, readily available to the designer, that explains the
principal functions of the different electronic warfare systems, what the vul-
nerable parts of radars are, what the limitations of weapon systems are, and
what makes an electronic defense system effective.
Taking advantage of my experience as a designer of radar and weapon
systems, I thought that a single volume describing the operating principles of
both weapon systems and electronic defense systems might be useful to those
wishing or needing to enter the field.
The book is addressed to those who are about to start working as
designers of these systems, to those who are or will become their users, and to
those who administer their procurement.
The formulas and the mathematical theory have been reduced to a
minimum, and readers are frequently invited to consult the appropriate ref-
erences for in-depth analyses. The book can therefore be read and under-
stood by anyone with a secondary education and interest in the systems used
by the armed forces.
The book is divided into eight chapters. Chapter 1 explains briefly the
usefulness of electronic defense, how it is organized, and what systems it
includes. In addition, it describes the operational objectives of electronic
defense.
Chapter 2 analyzes the sensors of weapon systems in order to highlight
their merits and, above all, their limits. The objective is to help the designer
exploit their weaknesses.
xvii
xviii Introduction to Electronic Defense Systems
Chapter 3 gives examples of ardlery and missile systems that use the
electronic sensors described in Chapter 2, again with the objective of empha-
sizing how their effectiveness may be reduced.
-chapter 4 describes and- analyzes electronic systems dedicated to
passive interception, generally known as electronic support measures (ESM).
Both those using radio-frequency emissions and those using infrared are
described.
Chapter 5 is devoted to the more striking part of electronic defense:
electronic countermeasures (ECM); that is, the generation of signals that, by
interfering with the receivers of "victim" systems, cause a degradation in the
performance of the associated weapon systems.
Since weapon systems can undergo intentional jamming aimed at
reducing their capabilities, they have been equipped with counter-
countermeasures (ECCM) systems. These systems and their applications are
described in Chapter 6, which gives an account of their effectiveness.
The thrust and parry of countermeasures and counter-countermeasures
seem to have no end,-and new technologies ensure that it is now possible to
attack the very operating principles ofweapon systems, which makes the
development of effective counter-countermeasures very difficult. Chapter 7
describes this technolog-i cal advance.
Finally, to assist designers in achieving the optimum solution of the
design problems described in Chapters 4 and 5, Chapter 8 lists the criteria
that should be followed during the design stage of electronic defense systems.
Chapter 8 also discusses the methods of evaluation and simulation that can
determine whether a system is really effective. This should be particularly
helpful to those who have to decide on the choice of an electronic defense
system.
I hope that this book will be found useful. It is best seen as a simple ref-
erence book for the rapid evaluation and organization of material. In the end,
the quality of a system and the achievement of its operational objectives will
depend, as always, on the ability, the preparation, and the dedication of those
who have to perform the work.
Acknowledgments
I thank Enzo Benigni (president of Elettronica SpA), Gabriele Gambarara
(general manager), and Giuseppe Maresca (marketing & sales director), for
the encouragement they gave me while I was writing the second edition of
this book.
A special thank you to my first teacher on Radar Systems, Piero Guargua-
glini (President of Finmeccanica) for the many discussions and suggestions
on Radar and EW techniques.
I also thank my colleagues at Elettronica SpA and at other firms and
organizations who have collaborated in the writing:
Andrea De Martino and V. Rossi for their help and for material on
radar systems; M. Grazzini for SAR technique; S. Scarfb and A. Zaccaron for
contributions to and revision of the material on digital receiver, DRFM, and
location techniques; S. Spillo for ESM receivers; F. Conte for ECM mate-
rial revision; A. Bacchelli for advanced identification techniques; G. Pinto for
microwave technology; A. Zammit for electro-optics technology revision; G.
Broli and M. Stinco for ELINT systems; Candidoro Giannicchi for revision
of material on tracking systems; J. Marks for chaff revision; D. Autiero for
shared apertures; Michele Russo for contributions on telecommunications
systems; L. Girardi, G. Carlini, E. Nitoglia, and L. Caprioli for the artwork.
In particular, I thank: Ubaldo Menegotti, ESM & IW manager, Elet-
tronica SPA, for information warfare; Vic Pheasant, international counter-
measures director, Chemring Group Plc, for chaff and flares; and Silvano
Padovani, technical director, FIAR SPA, for airborne radar.
Filippo Neri
Rome, Italy
August 2001
xix
v
Contents

Foreword xv
Preface xvii
Acknowledgments xix
1. Electronic Defense 1
1.1 Introduction 1
1.2 Systems in Use in the Armed Forces 3
1.2.1 The Air Force 3
1.2.2 The Navy 11
1.2.3 The Army 18
1.3 The Main Weapon Systems 21
1.4 The Objectives of Electronic Defense 23
1.4.1 The Organization of Electronic Defense 23
1.5 Electronic Defense Systems and Their Operational Objective 24
1.6 Information 33
1.6.1 Information Operation (IO) 34
1.6.2 Information Warfare (IW) 34
1.7 Need for the Study of Weapon Systems 36
References 36
2. Sensors 37
2.1 Introduction 37
2.2 Radar Sensors 37
2.2.1 Review of Electromagnetic Signal Transmission 37
2.2.2 The Radar Equation 44
2.2.3 Radar Equation in the Operational Environment 67
2.2.4 Radar Techniques 86
2.2.5 Search Radar 111
2.2.6 Synthetic Aperture Radar (SAR) 127
2.2.7 Tracking Radars 135
2.2.8 Airborne Radars (Interceptors) 170
2.3 Infrared Sensors 196
2.3.1 Review of Radiant Energy 196
2.3.2 Infrared Radiation Produced by Targets of Interest 204
2.3.3 IR Range Equation 210
2.3.4 Suppression of Background Effects 216
2.3.5 IR Systems 217
References 219
3. Weapon Systems 223
3.1 Introduction 223
3.2 Artillery Systems 225
3.2.1 Firing Accuracy 226
3.2.2 Susceptibility to Jamming of an Artillery System 229
3.3 Missile Systems 230
3.3.1 Command Missiles 232
3.3.2 Beam-Riding Missiles 234
3.3.3 Semiactive Homing Missiles 235
3.3.4 Active Homing Missiles 240
3.3.5 Track-Via-Missile (TVM) Systems 240
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3.3.6 Passive IR-Guided Missiles 241
3.3.7 Sea-Skimming Missiles 248
3.4 Passive Antiradiation Missiles 250
3.5 Laser Weapon Systems 253
3.5.1 The Laser 253
3.5.2 The Laser Equation 255
3.5.3 Laser Applications 256
3.6 Stealth Aircraft 257
3.7 Communications Systems 260
3.7.1 Networks 260
3.7.2 Types of Transmission (Links) 262
3.7.3 The Message 267
3.7.4 Examples of Communications Systems 270
3.8 Information Operations (10) 272
3.8.1 Information Cycle: The OODA Loop 273
3.8.2 Information Processes and Tools 275
3.8.3 Information Contents (on Subjects or Events) 277
3.8.4 Parameters Defining Information Value 278
3.8.5 Information in War Operations 280
References 280
4. Electronic Intercept Systems 283
4.1 Introduction 283
4.2 The Equation of a Passive System 284
4.3 Radar Warning Receivers 286
4.3.1 RWR Sensitivity 287
4.4 Electronic Support Measures 290
4.4.1 Omnidirectional Antennas 298
4.4.2 Antennas for Direction Finding 298
4.4.3 Frequency Measurement Receiver 298
4.4.4 Channelized Receivers 309
4.4.5 Direction of Arrival (DOA) Measurement 324
4.4.6 Pulsewidth Measurement 331
4.4.7 MOP Measurements 331
4.4.8 Automatic Detection 341
4.4.9 Identification and Data Processing 345
4.4.10 Presentation 345
4.4.11 Problem Areas in ESM 347
4.4.12 Typical Characteristics of a Naval ESM System 348
4.4.13 Range Advance Factor in the Operational Environment 349
4.5 Electronic Intelligence (ELINT) Systems 351
4.5.1 ELINT Sensors 352
4.5.2 Surveillance Network 354
4.5.3 The ELINT Processing Center (EWAC) 354
4.6 Advanced Passive Location Techniques 356
4.6.1 Doppler Shift 356
4.6.2 LBI 358
4.6.3 PRI Shift 360
4.7 Infrared Intercept Systems 361
4.7.1 Missile Launch Warner/Missile Approach Warner 362
4.7.2 Forward-Looking Infrared Systems 363
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4.8 Communications ESM and Communication Intelligence 363
4.8.1 Communications ESM 364
4.8.2 COMINT 368
References 369
5. Electronic Countermeasures Systems 373
5.1 Introduction 373
5.1.1 Operational Jamming Modes: SPJ, SOJ, and EJ 373
5.2 Onboard ECM Systems 376
5.2.1 Passive Systems 376
5.2.2 Active Systems 381
5.2.3 The Jammer Equations 396
5.2.4 The DRFM 402
5.2.5 Transmitters 414
5.2.6 ECM Antennas 416
5.2.7 The Pod 424
5.3 ECM Techniques 426
5.3.1 Spot Noise 426
5.3.2 Barrage Noise 427
5.3.3 Swept Noise/CW 428
5.3.4 Gated Noise 428
5.3.5 Amplitude-Modulated Noise/CW 429
5.3.6 Multiple False-Target Generation 434
5.3.7 Range Gate Pull-Off 435
5.3.8 Velocity Gate Pull-Off 437
5.3.9 Dual Mode 438
5.3.10 Inverse Gain 439
5.3.11 Countdown 439
5.3.12 Cooperative Jamming 442
5.3.13 Cross-Polarization 443
5.3.14 Cross-Eye (Virtual Off-Board Decoy) 446
5.3.15 Terrain Bounce 451
5.3.16 Illuminated Chaff 452
5.3.17 High-Resolution Radar Jamming 452
5.4 Infrared Countermeasures (IRCM) 456
5.4.1 Modulated Sources 456
5.4.2 Laser IRCM 457
5.5 Off-Board ECM Systems 457
5.5.1 Passive Systems 457
5.5.2 Active Systems 468
5.6 Communications Countermeasures (COM-ECM) 482
5.7 Information Warfare (IW) 484
5.7.1 Information Countermeasures (Counter Information) 484
5.7.2 Information Counter-Countermeasures 485
References 487
6. Electronic Counter-Countermeasures Systems 489
6.1 Introduction 489
6.2 Search Radar Counter-Countermeasures 489
6.2.1 Induced Counter-Countermeasures 490
6.2.2 Dedicated Counter-Countermeasures 501
6.3 Tracking Radar Counter-Countermeasures 506
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