The document provides biographical information about Merrill Skolnik, the editor in chief of the Radar Handbook. It notes that Skolnik was the superintendent of the Radar Division at the U.S. Naval Research Laboratory for over 30 years and was involved in advances in radar at MIT Lincoln Laboratory, the Institute for Defense Analyses, and Electronic Communications, Inc. It also states that Skolnik authored the popular textbook Introduction to Radar Systems and was the editor of Radar Applications as well as a former editor of the Proceedings of the IEEE.

2. ii
ABOUT THE EDITOR IN CHIEF
Merrill Skolnik was Superintendent of the Radar Division at the U.S. Naval Research Laboratory for over 30
years. Before that he was involved in advances in radar while at the MIT Lincoln Laboratory, the Institute for
Defense Analyses, and the Research Division of Electronic Communications, Inc. He is the author of the
popular McGraw-Hill textbook Introduction to Radar Systems, now in its third edition, the editor of Radar
Applications, as well as being a former editor of the Proceedings of the IEEE. He earned the Doctor of
Engineering Degree from The Johns Hopkins University, where he also received the B.E and M.S.E degrees in
electrical engineering. He is a member of the U.S. National Academy of Engineering, a Fellow of the IEEE,
and the first recipient of the IEEE Dennis J. Picard Medal for Radar Technologies and Applications.

3. iii
RADAR HANDBOOK
Merrill I. Skolnik
Editor in Chief
Third Edition
New York Chicago San Francisco Lisbon London Madrid
Mexico City Milan New Delhi San Juan Seoul
Singapore Sydney Toronto

4. iv
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Radar Handbook, Third Edition
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from the use of such information.

5. v
CONTENTS
Contributors xiii
Preface xv
Chapter 1 An Introduction and Overview of Radar
Merrill Skolnik
1.1
1.1 Radar in Brief / 1.1
1.2 Types of Radars / 1.5
1.3 Information Available from a Radar / 1.7
1.4 The Radar Equation / 1.10
1.5 Radar Frequency Letter-band Nomenclature / 1.13
1.6 Effect of Operating Frequency on Radar / 1.14
1.7 Radar Nomenclature / 1.18
1.8 Some Past Advances in Radar / 1.19
1.9 Applications of Radar / 1.20
1.10 Conceptual Radar System Design / 1.22
Chapter 2 MTI Radar
William W. Shrader and Vilhelm Gregers-Hansen
2.1
2.1 Preface / 2.1
2.2 Introduction to MTI Radar / 2.2
2.3 Clutter Filter Response to Moving Targets / 2.9
2.4 Clutter Characteristics / 2.10
2.5 Definitions / 2.19
2.6 Improvement Factor Calculations / 2.23
2.7 Optimum Design of Clutter Filters / 2.25
2.8 MTI Clutter Filter Design / 2.33
2.9 MTI Filter Design for Weather Radars / 2.46
2.10 Clutter Filter Bank Design / 2.52
2.11 Performance Degradation Caused by Receiver Limiting / 2.59
2.12 Radar System Stability Requirements / 2.65
2.13 Dynamic Range and A/D Conversion Considerations / 2.78
2.14 Adaptive MTI / 2.80
2.15 Radar Clutter Maps / 2.83

6. 2.16 Sensitivity-velocity Control (SVC) / 2.87
2.17 Considerations Applicable to MTI Radar Systems / 2.91

7. vi
Chapter 3 Airborne MTI
James K. Day and Fred M. Staudaher
3.1
3.1 Systems Using Airborne MTI Techniques / 3.1
3.2 Coverage Considerations / 3.2
3.3 Airborne MTI Performance Drivers / 3.3
3.4 Platform Motion and Altitude Effects on MTI Performance / 3.3
3.5 Platform-motion Compensation Abeam / 3.10
3.6 Scanning-motion Compensation / 3.14
3.7 Simultaneous Platform Motion and Scan Compensation / 3.18
3.8 Platform-motion Compensation, Forward Direction / 3.21
3.9 Space-time Adaptive Motion Compensation / 3.23
3.10 Effect of Multiple Spectra / 3.31
3.11 Example AMTI Radar System / 3.32
Chapter 4 Pulse Doppler Radar
John P. Stralka and William G. Fedarko
4.1
4.1 Characteristics and Applications / 4.1
4.2 Pulse Doppler Clutter / 4.14
4.3 Dynamic-range and Stability Requirements / 4.24
4.4 Range and Doppler Ambiguity Resoluton / 4.31
4.5 Mode and Waveform Design / 4.35
4.6 Range Performance / 4.39
List of Abbreviations / 4.48
Chapter 5 Multifunctional Radar Systems for Fighter Aircraft
David Lynch, Jr. and Carlo Kopp
5.1
5.1 Introduction / 5.1
5.2 Typical Missions and Modes / 5.10
5.3 A-A Mode Descriptions & Waveforms / 5.16
5.4 A-S Mode Descriptions & Waveforms / 5.28
Chapter 6 Radar Receivers
Michael E. Yeomans
6.1
6.1 The Configuration of a Radar Receiver / 6.1
6.2 Noise and Dynamic-range Considerations / 6.4
6.3 Bandwidth Considerations / 6.9
6.4 Receiver Front End / 6.10
6.5 Local Oscillators / 6.14
6.6 Gain Control / 6.22
6.7 Filtering / 6.24

8. 6.8 Limiters / 6.29
6.9 I/Q Demodulators / 6.31
6.10 Analog-to-Digital Converters / 6.35
6.11 Digital Receivers / 6.40
6.12 Diplex Operation / 6.46
6.13 Waveform Generation and Upconversion / 6.47

9. vii
Chapter 7 Automatic Detection, Tracking, and Sensor Integration
W. G. Bath and G. V.Trunk
7.1
7.1 Introduction / 7.1
7.2 Automatic Detection / 7.1
7.3 Automatic Tracking / 7.22
7.4 Networked Radars / 7.46
7.5 Unlike-sensor Integration / 7.49
Chapter 8 Pulse Compression Radar
Michael R. Ducoff and Byron W. Tietjen
8.1
8.1 Introduction / 8.1
8.2 Pulse Compression Waveform Types / 8.2
8.3 Factors Affecting Choice of Pulse Compression Systems / 8.26
8.4 Pulse Compression Implementation and Radar System Examples / 8.28
Appendix / 8.36
Chapter 9 Tracking Radar
Dean D. Howard
9.1
9.1 Introduction / 9.1
9.2 Monopulse (Simultaneous Lobing) / 9.3
9.3 Scanning and Lobing / 9.16
9.4 Servosystems for Tracking Radar / 9.17
9.5 Target Acquisition and Range Tracking / 9.20
9.6 Special Monopulse Techniques / 9.24
9.7 Sources of Error / 9.26
9.8 Target-caused Errors (Target Noise) / 9.26
9.9 Other External Causes of Error / 9.37
9.10 Internal Sources of Error / 9.42
9.11 Summary of Sources of Error / 9.43
9.12 Error Reduction Techniques / 9.46
Chapter 10 The Radar Transmitter
Thomas A. Weil and Merrill Skolnik
10.1
10.1 Introduction / 10.1
10.2 Linear-beam Amplifiers / 10.4
10.3 Magnetron / 10.14
10.4 Crossed-field Amplifiers / 10.16
10.5 Gyrotrons / 10.17
10.6 Transmitter Spectrum Control / 10.19
10.7 Grid-controlled Tubes / 10.21

10. 10.8 Modulators / 10.23
10.9 Which RF Power Source to Use? / 10.25

11. viii
Chapter 11 Solid id-State Transmitters
Michael T. Borkowski
11.1
11.1 Introduction / 11.1
11.2 Advantages of Solid State / 11.1
11.3 Solid-state Devices / 11.5
11.4 Designing for the Solid-state Bottle Transmitter / 11.17
11.5 Designing for the Solid-state Phased Array Transmitter / 11.24
11.6 Solid-state System Examples / 11.37
Chapter 12 Reflector Antennas
Michael E. Cooley and Daniel Davis
12.1
12.1 Introduction / 12.7
12.2 Basic Principles and Parameters / 12.3
12.3 Reflector Antenna Architectures / 12.16
12.4 Reflector Feeds / 12.25
12.5 Reflector Antenna Analysis / 12.37
12.6 Mechanical Design Considerations / 12.35
Acknowledgments / 12.47
Chapter 13 Phased Array Radar Antennas
Joe Frank and John D. Richards
13.1
13.1 Introduction / 13.7
13.2 Array Theory / 13.9
13.3 Planar Arrays and Beam Steering / 13.15
13.4 Aperture Matching and Mutual Coupling / 13.20
13.5 Low-sidelobe Phased Arrays / 13.28
13.6 Quantization Effects / 13.34
13.7 Bandwidth of Phased Arrays / 13.38
13.8 Feed Networks (Beamformers) / 13.46
13.9 Phase Shifters / 13.57
13.10 Solid-state Modules / 13.53
13.11 Multiple Simultaneous Receive Beams / 13.54
13.12 Digital Beamforming / 13.56
13.13 Radiation Pattern Nulling / 13.57
13.14 Calibration of Active Phased Array Antennas / 13.60
13.15 Phased Array Systems / 13.62
Chapter 14 Radar Cross Section
Eugene F. Knott
14.1
14.1 Introduction / 14.1

12. 14.2 The Concept of Echo Power / 14.4
14.3 RCS Prediction Techniques / 14.16
14.4 RCS Measurement Techniques / 14.27
14.5 Radar Echo Suppression / 14.36

13. ix
Chapter 15 Sea Clutter
Lewis B. Wetzel
15.1
15.1 Introduction / 15.1
15.2 The Sea Surface / 15.3
15.3 Empirical Behavior of Sea Clutter / 15.7
15.4 Theories and Models of Sea Clutter / 15.27
15.5 Summary and Conclusions / 15.37
Chapter 16 Ground Echo
Richard K. Moore
16.1
16.1 Introduction / 16.1
16.2 Parameters Affecting Ground Return / 16.4
16.3 Theoretical Models and Their Limitations / 16.7
16.4 Fading of Ground Echoes / 16.12
16.5 Measurement Techniques for Ground Return / 16.19
16.6 General Models for Scattering Coefficient (Clutter Models) / 16.29
16.7 Scattering Coefficient Data / 16.35
16.8 Polarimetry / 16.46
16.9 Scattering Coefficient Data Near Grazing / 16.52
16.10 Imaging Radar Interpretation / 16.55
Chapter 17 Synthetic Aperture Radar
Roger Sullivan
17.1
17.1 Basic Principle of SAR / 17.1
17.2 Early History of SAR / 17.2
17.3 Types of SAR / 17.2
17.4 SAR Resolution / 17.6
17.5 Key Aspects of SAR / 17.10
17.6 SAR Image Quality / 17.16
17.7 Summary of Key SAR Equations / 17.21
17.8 Special SAR Applications / 17.22
Chapter 18 Space-Based Remote Sensing Radars
R. Keith Raney
18.1
18.1 Perspective / 18.1
18.2 Synthetic Aperture Radar (SAR) / 18.5
18.3 Altimeters / 18.29
18.4 Planetary Radars / 18.43
18.5 Scatterometers / 18.53
18.6 Radar Sounders / 18.59

14. x
Chapter 19 Meteorological Radar
R. Jeffrey Keeler and Robert J. Serafin
19.1
19.1 Introduction / 19.1
19.2 The Radar Equation for Meteorological Targets / 19.3
19.3 Design Considerations / 19.6
19.4 Signal Processing / 19.19
19.5 Operational Applications / 19.25
19.6 Research Applications / 19.33
Chapter 20 HF Over-the-Horizon Radar
James M. Headrick and Stuart J. Anderson
20.1
20.1 Introduction / 20.1
20.2 The Radar Equation / 20.5
20.3 Factors Influencing Skywave Radar Design / 20.7
20.4 The Ionosphere and Radiowave Propagation / 20.13
20.5 Waveforms for HF Radar / 20.21
20.6 The Transmitting System / 20.23
20.7 Radar Cross Section / 20.26
20.8 Clutter: Echoes from the Environment / 20.29
20.9 Noise, Interference, and Spectrum Occupancy / 20.40
20.10 The Receiving System / 20.45
20.11 Signal Processing and Tracking / 20.49
20.12 Radar Resource Management / 20.54
20.13 Radar Performance Modeling / 20.55
Appendix: HF Surface Wave Radar / 20.70
Chapter 21 Ground Penetrating Radar
David Daniels
21.1
21.1 Introduction / 21.1
21.2 Physics of Propagation in Materials / 21.6
21.3 Modeling / 21.13
21.4 Properties of Materials / 21.18
21.5 GPR Systems / 21.20
21.6 Modulation Techniques / 21.21
21.7 Antennas / 21.24
21.8 Signal and Image Processing / 21.30
21.9 Applications / 21.35
21.10 Licensing / 21.39

15. Chapter 22 Civil Marine Radar
Andy Norris
22.1
22.1 Introduction / 22.1
22.2 The Challenges / 22.3
22.3 International Standards / 22.7
22.4 Technology / 22.10
22.5 Target Tracking / 22.17

16. xi
22.6 User Interface / 22.19
22.7 Integration with AIS / 22.23
22.8 Radar Beacons / 22.25
22.9 Validation Testing / 22.28
22.10 Vessel Tracking Services / 22.29
Appendix The Early Days of CMR / 22.31
List of Maritime Radar-related Abbreviations / 22.33
Acknowledgments / 22.34
Chapter 23 Bistatic Radar
Nicholas J. Willis
23.1
23.1 Concept and Definitions / 23.1
23.2 Coordinate Systems / 23.3
23.3 Bistatic Radar Equation / 23.4
23.4 Applications / 23.9
23.5 Bistatic Doppler / 23.14
23.6 Target Location / 23.17
23.7 Target Cross Section / 23.19
23.8 Surface Clutter / 23.22
23.9 Unique Problems and Requirements / 23.26
Chapter 24 Electronic Counter-Countermeasures
Alfonso Farina
24.1
24.1 Introduction / 24.1
24.2 Terminology / 24.2
24.3 Electronic Warfare Support Measures / 24.2
24.4 Electronic Countermeasures / 24.5
24.5 Objectives and Taxonomy of ECCM Techniques / 24.8
24.6 Antenna-related ECCM / 24.10
24.7 Transmitter-related ECCM / 24.31
24.8 Receiver-related ECCM / 24.32
24.9 Signal-processing-related ECCM / 24.33
24.10 Operational-deployment Techniques / 24.36
24.11 Application of ECCM Techniques / 24.37
24.12 ECCM and ECM Efficacy / 24.54
Acronym List / 24.56
Acknowledgments / 24.58

17. Chapter 25 Radar Digital Signal Processing
James J. Alter and Jeffrey O. Coleman
25.1
25.1 Introduction / 25.1
25.2 Receive Channel Processing / 25.2
25.3 Transmit Channel Processing / 25.20
25.4 DSP Tools / 25.22
25.5 Design Considerations / 25.34
25.6 Summary / 25.37
Acknowledgments / 25.38

18. xii
Chapter 26 The Propagation Factor, Fp, in the Radar Equation
Wayne L. Patterson
26.1
26.1 Introduction / 26.1
26.2 The Earth’s Atmosphere / 26.2
26.3 Refraction / 26.3
26.4 Standard Propagation / 26.4
26.5 Anomalous Propagation / 26.6
26.6 Propagation Modeling / 26.13
26.7 EM System Assessment Programs / 26.18
26.8 AREPS Radar System Assessment Model / 26.23
26.9 AREPS Radar Displays / 26.25
Index 1.1

19. xiii
CONTRIBUTORS
James J. Alter Naval Research Laboratory (CHAPTER 25)
Stuart J. Anderson Australian Defense Science and Technology Organisation (CHAPTER 20)
W. G. Bath The Johns Hopkins University Applied Physics Laboratory (CHAPTER 7)
Michael T. Borkowski Raytheon Company (CHAPTER 11)
Jeffrey O. Coleman Naval Research Laboratory (CHAPTER 25)
Michael E. Cooley Northrop Grumman, Electronic Systems (CHAPTER 12)
David Daniels ERA Technology (CHAPTER 21)
Daniel Davis Northrop Grumman Corporation (CHAPTER 12)
James K. Day Lockheed Martin Corporation (CHAPTER 3)
Michael R. Ducoff Lockheed Martin Corporation (CHAPTER 8)
Alfonso Farina SELEX Sistemi Integrati (CHAPTER 24)
William G. Fedarko Northrop Grumman Corporation (CHAPTER 4)
Joe Frank The Johns Hopkins University Applied Physics Laboratory (CHAPTER 13)
Vilhelm Gregers-Hansen Naval Research Laboratory (CHAPTER 2)
James M. Headrick Naval Research Laboratory, retired (CHAPTER 20)
Dean D. Howard Consultant to ITT Industries, Inc. (CHAPTER 9)
R. Jeffrey Keeler National Center for Atmospheric Research (CHAPTER 19)
Eugene F. Knott Tomorrow’s Research (CHAPTER 14)
Carlo Kopp Monash University (CHAPTER 5)
David Lynch, Jr. DL Sciences, Inc. (CHAPTER 5)
Richard K. Moore The University of Kansas (CHAPTER 16)
Andy Norris Consultant in Navigation Systems (CHAPTER 22)
Wayne L. Patterson Space and Naval Warfare Systems Center (CHAPTER 26)
Keith Raney The Johns Hopkins University Applied Physics Laboratory (CHAPTER 18)
John D. Richards The Johns Hopkins University Applied Physics Laboratory (CHAPTER 13)
Robert J. Serafin National Center for Atmospheric Research (CHAPTER 19)
William W. Shrader Shrader Associates (CHAPTER 2)
Merrill Skolnik (CHAPTERS 1 and 10)
Fred M. Staudaher Naval Research Laboratory, retired (CHAPTER 3)

20. xiv
John P. Stralka Northrop Grumman Corporation (CHAPTER 4)
Roger Sullivan Institute for Defense Analyses (CHAPTER 17)
Byron W. Tietjen Lockheed Martin Corporation (CHAPTER 8)
G. V. Trunk The Johns Hopkins University Applied Physics Laboratory (CHAPTER 7)
Thomas A. Weil (CHAPTER 10)
Lewis B. Wetzel Naval Research Laboratory, retired (CHAPTER 15)
Nicholas J. Willis Technology Service Corporation, retired (CHAPTER 23)
Michael E. Yeomans Raytheon Company (CHAPTER 6)

21. xv
PREFACE
Radar is an important example of an electrical engineering system. In university engineering courses, the
emphasis usually is on the basic tools of the electrical engineer such as circuit design, signals, solid state,
digital processing, electronic devices, electromagnetics, automatic control, microwaves, and so forth. But in
the real world of electrical engineering practice, these are only the techniques, piece parts, or subsystems that
make up some type of system employed for a useful purpose. In addition to radar and other sensor systems,
electrical engineering systems include communications, control, energy, information, industrial, military,
navigation, entertainment, medical, and others. These are what the practice of electrical engineering is all
about. Without them there would be little need for electrical engineers. However, the practicing engineer who
is involved in producing a new type of electrical engineering system often has to depend on acquiring
knowledge that was not usually covered in his or her engineering courses. The radar engineer, for example,
has to understand the major components and subsystems that make up a radar, as well as how they fit
together. The Radar Handbook attempts to help in this task. In addition to the radar system designer, it is
hoped that those who are responsible for procuring new radar systems, those who utilize radars, those who
maintain radar systems, and those who manage the engineers who do the above, also will find the Radar
Handbook to be of help in fulfilling such tasks.
The third edition of the Radar Handbook is evidence that the development and application of radar for both
civilian and military purposes continue to grow in both utility and in improved technology. Some of the many
advances in radar since the previous edition include the following:
- The extensive use of digital methods for improved signal processing, data processing, decision making,
flexible radar control, and multifunction radar
- Doppler weather radar
- Ground moving target indication, or GMTI
- An extensive experimental database describing low-angle land clutter, as obtained by MIT Lincoln
Laboratory, that replaced the previously widely used clutter model that dated back to World War II
- The realization that microwave sea echo at low grazing angles is due chiefly to what are called “sea spikes”
- The active-aperture phased array radar system using solid-state modules, also called active electronically
scanned arrays (AESA), which is attractive for some multifunction radar applications that need to manage
both power and spatial coverage
- Planetary exploration with radar
- Computer-based methods for predicting radar propagation performance in realistic environments

22. xvi
- Operational use of HF over-the-horizon radar
- Improved methods for detecting moving targets in clutter, including space-time adaptive processing
- Operational use of inverse synthetic aperture radar for target recognition
- Interferometric synthetic aperture radar, or InSAR, to obtain the height of a resolved scatterer or to detect
moving ground targets as well as provide a SAR image of a scene
- High precision space-based altimeters, with accuracy of a few centimeters, to measure the Earth’s geoid
- Ultrawideband radar for ground penetrating and similar applications
- Improved high power, wide bandwidth klystron power sources based on clustered cavity resonators, as well
as the multiple-beam klystron
- The appearance of wide bandgap semiconductors that allow better performance because of high power and
high operating temperatures
- The availability of high-power millimeter-wave generators based on the gyroklystron
- Nonlinear FM pulse compression with low sidelobe levels
- The replacement, by the computer, of the operator as information extractor and decision maker
The above are not listed in any particular order, nor should they be considered a complete enumeration of
radar developments since the appearance of the previous edition. There were also some radar topics in
previous editions of the Radar Handbook that are of lesser interest and so were not included in this edition.
The chapter authors, who are experts in their particular field, were told to consider the reader of their
chapter as being knowledgeable in the general subject of radar and even an expert in some other particular
area of radar, but not necessarily knowledgeable about the subject of the particular chapter the author was
writing.
It should be expected that with a book in print as long as the Radar Handbook has been, not all chapter
authors from the previous editions would be available to do the third edition. Many of the previous authors
have retired or are no longer with us. Sixteen of the twenty-six chapters in this edition have authors or
coauthors who were not involved in the previous editions.
The hard work of preparing these chapters was done by the individual expert authors of the various
chapters. Thus the value of the Radar Handbook is the result of the diligence and expertise of the authors who
contributed their time, knowledge, and experience to make this handbook a useful addition to the desk of radar
system engineers and all those people vital to the development, production, and employment of radar systems.
I am deeply grateful to all the contributing authors for their fine work and the long hours they had to apply to
their task. It is the chapter authors who make any handbook a success. My sincere thanks to them all.
As stated in the Preface of the previous edition, readers who wish to reference or quote material from the
Radar Handbook are asked to mention the names of the individual chapter authors who produced the material.
MERRILL SKOLNIK
Baltimore, Maryland

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POLES

57. SEA

58. ICE

59. ICEBERGS

60. BUOYS

61. UNDERGROUNDFEATURES

62. METEORS

63. AURORA

64. SPACECRAFT

65. ANDPLANETS)NADDITIONTOMEASURINGTHERANGETOATARGETASWELLASITSANGULARDIREC
TION

66. ARADARCANALSOFINDTHERELATIVEVELOCITYOFATARGETEITHERBYDETERMININGTHE
RATEOFCHANGEOFTHERANGEMEASUREMENTWITHTIMEORBYEXTRACTINGTHERADIALVELOCITY
FROMTHEDOPPLERFREQUENCYSHIFTOFTHEECHOSIGNAL)FTHELOCATIONOFAMOVINGTARGETIS
MEASUREDOVERAPERIODOFTIME

67. THETRACK

68. ORTRAJECTORY

69. OFTHETARGETCANBEFOUNDFROM
WHICHTHEABSOLUTEVELOCITYOFTHETARGETANDITSDIRECTIONOFTRAVELCANBEDETERMINED
ANDAPREDICTIONCANBEMADEASTOITSFUTURELOCATION0ROPERLYDESIGNEDRADARSCAN
DETERMINETHESIZEANDSHAPEOFATARGETANDMIGHTEVENBEABLETORECOGNIZEONETYPE
ORCLASSOFTARGETFROMANOTHER
ASIC0ARTSOFA2ADAR IGUREISAVERYELEMENTARYBASICBLOCKDIAGRAM
SHOWINGTHESUBSYSTEMSUSUALLYFOUNDINARADAR4HETRANSMITTER

70. WHICHISSHOWNHERE
ASAPOWERAMPLIFIER

71. GENERATESASUITABLEWAVEFORMFORTHEPARTICULARJOBTHERADARIS
TOPERFORM)TMIGHTHAVEANAVERAGEPOWERASSMALLASMILLIWATTSORASLARGEASMEGA
WATTS4HEAVERAGEPOWERISAFARBETTERINDICATIONOFTHECAPABILITYOFARADARSPERFOR
MANCETHANISITSPEAKPOWER -OSTRADARSUSEASHORTPULSEWAVEFORMSOTHATASINGLE
ANTENNACANBEUSEDONATIME
SHAREDBASISFORBOTHTRANSMITTINGANDRECEIVING
4HEFUNCTIONOFTHEDUPLEXERISTOALLOWASINGLEANTENNATOBEUSEDBYPROTECTING
THESENSITIVERECEIVERFROMBURNINGOUTWHILETHETRANSMITTERISONANDBYDIRECTINGTHE
RECEIVEDECHOSIGNALTOTHERECEIVERRATHERTHANTOTHETRANSMITTER
4HEANTENNAISTHEDEVICETHATALLOWSTHETRANSMITTEDENERGYTOBEPROPAGATEDINTO
SPACEANDTHENCOLLECTSTHEECHOENERGYONRECEIVE)TISALMOSTALWAYSADIRECTIVE
ANTENNA

72. ONETHATDIRECTSTHERADIATEDENERGYINTOANARROWBEAMTOCONCENTRATETHE
POWERASWELLASTOALLOWTHEDETERMINATIONOFTHEDIRECTIONTOTHETARGET!NANTENNA
THATPRODUCESANARROWDIRECTIVEBEAMONTRANSMITUSUALLYHASALARGEAREAONRECEIVE
TOALLOWTHECOLLECTIONOFWEAKECHOSIGNALSFROMTHETARGET4HEANTENNANOTONLY
CONCENTRATESTHEENERGYONTRANSMITANDCOLLECTSTHEECHOENERGYONRECEIVE

73. BUTITALSO
ACTSASASPATIALFILTERTOPROVIDEANGLERESOLUTIONANDOTHERCAPABILITIES
p
)NRADAR

74. RANGEISTHETERMGENERALLYUSEDTOMEANDISTANCEFROMTHERADARTOTHETARGET2ANGEISALSOUSEDHEREIN
SOMEOFITSOTHERDICTIONARYDEFINITIONS

75. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°Î
4HERECEIVERAMPLIFIESTHEWEAKRECEIVEDSIGNALTOALEVELWHEREITSPRESENCECAN
BEDETECTEDECAUSENOISEISTHEULTIMATELIMITATIONONTHEABILITYOFARADARTOMAKE
ARELIABLEDETECTIONDECISIONANDEXTRACTINFORMATIONABOUTTHETARGET

76. CAREISTAKEN
TOINSURETHATTHERECEIVERPRODUCESVERYLITTLENOISEOFITSOWN!TTHEMICROWAVE
FREQUENCIES

77. WHEREMOSTRADARSAREFOUND

78. THENOISETHATAFFECTSRADARPERFORMANCE
ISUSUALLYFROMTHEFIRSTSTAGEOFTHERECEIVER

79. SHOWNHEREINIGUREASALOW
NOISEAMPLIFIERORMANYRADARAPPLICATIONSWHERETHELIMITATIONTODETECTIONISTHE
UNWANTEDRADARECHOESFROMTHEENVIRONMENTCALLEDCLUTTER

80. THERECEIVERNEEDSTO
HAVEALARGEENOUGHDYNAMICRANGESOASTOAVOIDHAVINGTHECLUTTERECHOESADVERSELY
AFFECTDETECTIONOFWANTEDMOVINGTARGETSBYCAUSINGTHERECEIVERTOSATURATE4HE
DYNAMICRANGEOFARECEIVER

81. USUALLYEXPRESSEDINDECIBELS

82. ISDEFINED
ASTHERATIOOF
THEMAXIMUMTOTHEMINIMUMSIGNALINPUTPOWERLEVELSOVERWHICHTHERECEIVERCAN
OPERATEWITHSOMESPECIFIEDPERFORMANCE4HEMAXIMUMSIGNALLEVELMIGHTBESET
BYTHENONLINEAREFFECTSOFTHERECEIVERRESPONSETHATCANBETOLERATEDFOREXAMPLE

83. THESIGNALPOWERATWHICHTHERECEIVERBEGINSTOSATURATE

84. ANDTHEMINIMUMSIGNAL
MIGHTBETHEMINIMUMDETECTABLESIGNAL4HESIGNALPROCESSOR

85. WHICHISOFTENINTHE
)PORTIONOFTHERECEIVER

86. MIGHTBEDESCRIBEDASBEINGTHEPARTOFTHERECEIVERTHAT
SEPARATESTHEDESIREDSIGNALFROMTHEUNDESIREDSIGNALSTHATCANDEGRADETHEDETEC
TIONPROCESS3IGNALPROCESSINGINCLUDESTHEMATCHEDFILTERTHATMAXIMIZESTHEOUT
PUTSIGNAL
TO
NOISERATIO3IGNALPROCESSINGALSOINCLUDESTHEDOPPLERPROCESSINGTHAT
MAXIMIZESTHESIGNAL
TO
CLUTTERRATIOOFAMOVINGTARGETWHENCLUTTERISLARGERTHAN
RECEIVERNOISE

87. ANDITSEPARATESONEMOVINGTARGETFROMOTHERMOVINGTARGETSORFROM
CLUTTERECHOES4HEDETECTIONDECISIONISMADEATTHEOUTPUTOFTHERECEIVER

88. SOATARGET
ISDECLAREDTOBEPRESENTWHENTHERECEIVEROUTPUTEXCEEDSAPREDETERMINEDTHRESHOLD
)FTHETHRESHOLDISSETTOOLOW

89. THERECEIVERNOISECANCAUSEEXCESSIVEFALSEALARMS)F
THETHRESHOLDISSETTOOHIGH

90. DETECTIONSOFSOMETARGETSMIGHTBEMISSEDTHATWOULD
OTHERWISEHAVEBEENDETECTED4HECRITERIONFORDETERMININGTHELEVELOFTHEDECISION
THRESHOLDISTOSETTHETHRESHOLDSOITPRODUCESANACCEPTABLEPREDETERMINEDAVERAGE
RATEOFFALSEALARMSDUETORECEIVERNOISE
!FTERTHEDETECTIONDECISIONISMADE

91. THETRACKOFATARGETCANBEDETERMINED

92. WHERE
ATRACKISTHELOCUSOFTARGETLOCATIONSMEASUREDOVERTIME4HISISANEXAMPLEOFDATA
PROCESSING4HEPROCESSEDTARGETDETECTIONINFORMATIONORITSTRACKMIGHTBEDISPLAYED
TOANOPERATORORTHEDETECTIONINFORMATIONMIGHTBEUSEDTOAUTOMATICALLYGUIDEA
)'52% LOCKDIAGRAMOFASIMPLERADAREMPLOYINGAPOWERAMPLIFIERASTHETRANSMITTERINTHEUPPER
PORTIONOFTHEFIGUREANDASUPERHETERODYNERECEIVERINTHELOWERPORTIONOFTHEFIGURE

93. £°{ 2!$!2(!.$//+
MISSILETOATARGETORTHERADAROUTPUTMIGHTBEFURTHERPROCESSEDTOPROVIDEOTHER
INFORMATIONABOUTTHENATUREOFTHETARGET4HERADARCONTROLINSURESTHATTHEVARIOUS
PARTSOFARADAROPERATEINACOORDINATEDANDCOOPERATIVEMANNER

94. AS

95. FOREXAMPLE

96. PROVIDINGTIMINGSIGNALSTOVARIOUSPARTSOFTHERADARASREQUIRED
4HE RADAR ENGINEER HAS AS RESOURCES TIME THAT ALLOWS GOOD DOPPLER PROCESSING

97. BANDWIDTHFORGOODRANGERESOLUTION

98. SPACETHATALLOWSALARGEANTENNA

99. ANDENERGYFOR
LONGRANGEPERFORMANCEANDACCURATEMEASUREMENTS%XTERNALFACTORSAFFECTINGRADAR
PERFORMANCEINCLUDETHETARGETCHARACTERISTICSEXTERNALNOISETHATMIGHTENTERVIATHE
ANTENNAUNWANTEDCLUTTERECHOESFROMLAND

100. SEA

101. BIRDS

102. ORRAININTERFERENCEFROMOTHER
ELECTROMAGNETICRADIATORSANDPROPAGATIONEFFECTSDUETOTHEEARTHSSURFACEANDATMO
SPHERE4HESEFACTORSAREMENTIONEDTOEMPHASIZETHATTHEYCANBEHIGHLYIMPORTANTIN
THEDESIGNANDAPPLICATIONOFARADAR
2ADAR4RANSMITTERS 4HERADARTRANSMITTERMUSTNOTONLYBEABLETOGENERATETHE
PEAKANDAVERAGEPOWERSREQUIREDTODETECTTHEDESIREDTARGETSATTHEMAXIMUMRANGE

103. BUTALSOHASTOGENERATEASIGNALWITHTHEPROPERWAVEFORMANDTHESTABILITYNEEDEDFOR
THEPARTICULARAPPLICATION4RANSMITTERSMAYBEOSCILLATORSORAMPLIFIERS

104. BUTTHELATTER
USUALLYOFFERMOREADVANTAGES
4HEREHAVEBEENMANYTYPESOFRADARPOWERSOURCESUSEDINRADAR#HAPTER
4HEMAGNETRONPOWEROSCILLATORWASATONETIMEVERYPOPULAR

105. BUTITISSELDOMUSED
EXCEPTFORCIVILMARINERADAR#HAPTER ECAUSEOFTHEMAGNETRONSRELATIVELY
LOWAVERAGEPOWERONEORTWOKILOWATTS ANDPOORSTABILITY

106. OTHERPOWERSOURCES
AREUSUALLYMOREAPPROPRIATEFORAPPLICATIONSREQUIRINGLONG
RANGEDETECTIONOFSMALL
MOVINGTARGETSINTHEPRESENCEOFLARGECLUTTERECHOES4HEMAGNETRONPOWEROSCIL
LATORISANEXAMPLEOFWHATISCALLEDACROSSED
FIELDTUBE4HEREISALSOARELATED
CROSSED
FIELDAMPLIFIER#! THATHASBEENUSEDINSOMERADARSINTHEPAST

107. BUTIT
ALSOSUFFERSLIMITATIONSFORIMPORTANTRADARAPPLICATIONS

108. ESPECIALLYFORTHOSEREQUIR
INGDETECTIONOFMOVINGTARGETSINCLUTTER4HEHIGH
POWERKLYSTRONANDTHETRAVELING
WAVETUBE474 AREEXAMPLESOFWHATARECALLEDLINEARBEAMTUBES!TTHEHIGH
POWERSOFTENEMPLOYEDBYRADARS

109. BOTHTUBESHAVESUITABLYWIDEBANDWIDTHSASWELL
ASGOODSTABILITYASNEEDEDFORDOPPLERPROCESSING

110. ANDBOTHHAVEBEENPOPULAR
4HESOLID
STATEAMPLIFIER

111. SUCHASTHETRANSISTOR

112. HASALSOBEENUSEDINRADAR

113. ESPE
CIALLYINPHASEDARRAYS!LTHOUGHANINDIVIDUALTRANSISTORHASRELATIVELYLOWPOWER

114. EACHOFTHEMANYRADIATINGELEMENTSOFANARRAYANTENNACANUTILIZEMULTIPLETRANSISTORS
TOACHIEVETHEHIGHPOWERNEEDEDFORMANYRADARAPPLICATIONS7HENSOLID
STATETRAN
SISTORAMPLIFIERSAREUSED

115. THERADARDESIGNERHASTOBEABLETOACCOMMODATETHEHIGH
DUTYCYCLEATWHICHTHESEDEVICESHAVETOOPERATE

116. THELONGPULSESTHEYMUSTUSETHAT
REQUIREPULSECOMPRESSION

117. ANDTHEMULTIPLEPULSESOFDIFFERENTWIDTHSTOALLOWDETEC
TIONATSHORTASWELLASLONGRANGE4HUSTHEUSEOFSOLID
STATETRANSMITTERSCANHAVEAN
EFFECTONOTHERPARTSOFTHERADARSYSTEM!TMILLIMETERWAVELENGTHSVERYHIGHPOWER
CANBEOBTAINEDWITHTHEGYROTRON

118. EITHERASANAMPLIFIERORASANOSCILLATOR4HEGRID
CONTROLVACUUMTUBEWASUSEDTOGOODADVANTAGEFORALONGTIMEIN5(ANDLOWER
FREQUENCYRADARS

119. BUTTHEREHASBEENLESSINTERESTINTHELOWERFREQUENCIESFORRADAR
!LTHOUGH NOT EVERYONE MIGHT AGREE

120. SOME RADAR SYSTEM ENGINEERSˆIF GIVEN A
CHOICEˆWOULD CONSIDER THE KLYSTRON AMPLIFIER AS THE PRIME CANDIDATE FOR A HIGH
POWERMODERNRADARIFTHEAPPLICATIONWERESUITABLEFORITSUSE
2ADAR !NTENNAS 4HE ANTENNA IS WHAT CONNECTS THE RADAR TO THE OUTSIDE WORLD
#HAPTERSAND )TPERFORMSSEVERALPURPOSES CONCENTRATESTHERADIATEDENERGY

121. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°x
ONTRANSMITTHATIS

122. ITISDIRECTIVEANDHASANARROWBEAMWIDTH COLLECTSTHERECEIVED
ECHOENERGYFROMTHETARGET PROVIDESAMEASUREMENTOFTHEANGULARDIRECTIONTOTHE
TARGET PROVIDESSPATIALRESOLUTIONTORESOLVEORSEPARATE TARGETSINANGLEAND ALLOWS
THEDESIREDVOLUMEOFSPACETOBEOBSERVED4HEANTENNACANBEAMECHANICALLYSCANNED
PARABOLICREFLECTOR

123. AMECHANICALLYSCANNEDPLANARPHASEDARRAY

124. ORAMECHANICALLYSCANNED
END
FIREANTENNA)TCANBEANELECTRONICALLYSCANNEDPHASEDARRAYUSINGASINGLETRANSMIT
TERWITHEITHERACORPORATEFEEDORASPACE
FEEDCONFIGURATIONTODISTRIBUTETHEPOWERTO
EACHANTENNAELEMENTORANELECTRONICALLYSCANNEDPHASEDARRAYEMPLOYINGATEACHANTENNA
ELEMENTASMALLSOLID
STATEhMINIATUREvRADARALSOCALLEDANACTIVEAPERTUREPHASEDARRAY
%ACHTYPEOFANTENNAHASITSPARTICULARADVANTAGESANDLIMITATIONS'ENERALLY

125. THELARGERTHE
ANTENNATHEBETTER

126. BUTTHERECANBEPRACTICALCONSTRAINTSTHATLIMITITSSIZE
£°ÓÊ /9*
-ÊÊ,

127. ,-
!LTHOUGHTHEREISNOSINGLEWAYTOCHARACTERIZEARADAR

128. HEREWEDOSOBYMEANSOF
WHATMIGHTBETHEMAJORFEATURETHATDISTINGUISHESONETYPEOFRADARFROMANOTHER
0ULSERADAR4HISISARADARTHATRADIATESAREPETITIVESERIESOFALMOST
RECTANGULAR
PULSES)TMIGHTBECALLEDTHECANONICALFORMOFARADAR

129. THEONEUSUALLYTHOUGHTOF
ASARADARWHENNOTHINGELSEISSAIDTODEFINEARADAR
(IGH
RESOLUTIONRADAR(IGHRESOLUTIONCANBEOBTAINEDINTHERANGE

130. ANGLE

131. ORDOP
PLERVELOCITYCOORDINATES

132. BUTHIGHRESOLUTIONUSUALLYIMPLIESTHATTHERADARHASHIGH
RANGERESOLUTION3OMEHIGH
RESOLUTIONRADARSHAVERANGERESOLUTIONSINTERMSOF
FRACTIONSOFAMETER

133. BUTITCANBEASSMALLASAFEWCENTIMETERS
0ULSECOMPRESSIONRADAR4HISISARADARTHATUSESALONGPULSEWITHINTERNALMODU
LATIONUSUALLYFREQUENCYORPHASEMODULATION TOOBTAINTHEENERGYOFALONGPULSE
WITHTHERESOLUTIONOFASHORTPULSE
#ONTINUOUSWAVE#7 RADAR4HISRADAREMPLOYSACONTINUOUSSINEWAVE)TALMOST
ALWAYSUSESTHEDOPPLERFREQUENCYSHIFTFORDETECTINGMOVINGTARGETSORFORMEASUR
INGTHERELATIVEVELOCITYOFATARGET
-
#7RADAR4HIS#7RADARUSESFREQUENCYMODULATIONOFTHEWAVEFORMTOALLOW
ARANGEMEASUREMENT
3URVEILLANCERADAR!LTHOUGHADICTIONARYMIGHTNOTDEFINESURVEILLANCETHISWAY

134. A
SURVEILLANCERADARISONETHATDETECTSTHEPRESENCEOFATARGETSUCHASANAIRCRAFTOR
ASHIP ANDDETERMINESITSLOCATIONINRANGEANDANGLE)TCANALSOOBSERVETHETARGET
OVERAPERIODOFTIMESOASTOOBTAINITSTRACK
-OVINGTARGETINDICATION-4) 4HISISAPULSERADARTHATDETECTSMOVINGTARGETS
INCLUTTERBYUSINGALOWPULSEREPETITIONFREQUENCY02 THATUSUALLYHASNO
RANGEAMBIGUITIES)TDOESHAVEAMBIGUITIESINTHEDOPPLERDOMAINTHATRESULTIN
SO
CALLEDBLINDSPEEDS
0ULSEDOPPLERRADAR4HEREARETWOTYPESOFPULSEDOPPLERRADARSTHATEMPLOYEITHER
AHIGHORMEDIUM02PULSERADAR4HEYBOTHUSETHEDOPPLERFREQUENCYSHIFTTO
EXTRACTMOVINGTARGETSINCLUTTER!HIGH02PULSEDOPPLERRADARHASNOAMBIGUI
TIESBLINDSPEEDS INDOPPLER

135. BUTITDOESHAVERANGEAMBIGUITIES!MEDIUM02
PULSEDOPPLERRADARHASAMBIGUITIESINBOTHRANGEANDDOPPLER

136. £°È 2!$!2(!.$//+
4RACKINGRADAR4HISISARADARTHATPROVIDESTHETRACK

137. ORTRAJECTORY

138. OFATARGET
4RACKINGRADARSCANBEFURTHERDELINEATEDAS344

139. !$4

140. 473

141. ANDPHASEDARRAY
TRACKERSASDESCRIBEDBELOW
3INGLE4ARGET4RACKER344 4RACKSASINGLETARGETATADATARATEHIGHENOUGH
TOPROVIDEACCURATETRACKINGOFAMANEUVERINGTARGET!REVISITTIMEOFS
DATA RATE OF MEASUREMENTS PER SECOND MIGHT BE hTYPICALv )T MIGHT
EMPLOYTHEMONOPULSETRACKINGMETHODFORACCURATETRACKINGINFORMATIONIN
THEANGLECOORDINATE
!UTOMATICDETECTIONANDTRACKING!$4 4HISISTRACKINGPERFORMEDBYASUR
VEILLANCERADAR)TCANHAVEAVERYLARGENUMBEROFTARGETSINTRACKBYUSINGTHE
MEASUREMENTSOFTARGETLOCATIONSOBTAINEDOVERMULTIPLESCANSOFTHEANTENNA
)TSDATARATEISNOTASHIGHASTHE3442EVISITTIMESMIGHTRANGEFROMONETO
SECONDS

142. DEPENDINGONTHEAPPLICATION
4RACK
WHILE
SCAN473 5SUALLYARADARTHATPROVIDESSURVEILLANCEOVERANAR
ROW REGION OF ANGLE IN ONE OR TWO DIMENSIONS

143. SO AS TO PROVIDE AT A RAPID
UPDATERATELOCATIONINFORMATIONONALLTARGETSWITHINALIMITEDANGULARREGION
OFOBSERVATION)THASBEENUSEDINTHEPASTFORGROUND
BASEDRADARSTHATGUIDE
AIRCRAFTTOALANDING

144. INSOMETYPESOFWEAPON
CONTROLRADARS

145. ANDINSOME
MILITARYAIRBORNERADARS
0HASEDARRAYTRACKER!NELECTRONICALLYSCANNEDPHASEDARRAYCANALMOST hCON
TINUOUSLYvTRACKMORETHANONETARGETATAHIGHDATARATE)TCANALSOSIMULTA
NEOUSLYPROVIDETHELOWERDATARATETRACKINGOFMULTIPLETARGETSSIMILARTOTHAT
PERFORMEDBY!$4
)MAGINGRADAR4HISRADARPRODUCESATWO
DIMENSIONALIMAGEOFATARGETORASCENE

146. SUCHASAPORTIONOFTHESURFACEOFTHEEARTHANDWHATISONIT4HESERADARSUSUALLY
AREONMOVINGPLATFORMS
3IDELOOKINGAIRBORNERADAR3,!2 4HISAIRBORNESIDELOOKINGIMAGINGRADARPRO
VIDESHIGHRESOLUTIONINRANGEANDOBTAINSSUITABLERESOLUTIONINANGLEBYUSINGA
NARROWBEAMWIDTHANTENNA
3YNTHETICAPERTURERADAR3!2 3!2ISACOHERENT
IMAGINGRADARONAMOVING
VEHICLETHATUSESTHEPHASEINFORMATIONOFTHEECHOSIGNALTOOBTAINANIMAGEOFA
SCENEWITHHIGHRESOLUTIONINBOTHRANGEANDCROSS
RANGE(IGHRANGERESOLUTIONIS
OFTENOBTAINEDUSINGPULSECOMPRESSION
)NVERSESYNTHETICAPERTURERADAR)3!2 )3!2ISACOHERENTIMAGINGRADARTHATUSES
HIGHRESOLUTIONINRANGEANDTHERELATIVEMOTIONOFTHETARGETTOOBTAINHIGHRESOLU
TIONINTHEDOPPLERDOMAINTHATALLOWSRESOLUTIONINTHECROSS
RANGEDIMENSIONTO
BEOBTAINED)TCANBEONAMOVINGVEHICLEORITCANBESTATIONARY
7EAPONCONTROLRADAR4HISNAMEISUSUALLYAPPLIEDTOASINGLE
TARGETTRACKERUSED
FORDEFENDINGAGAINSTAIRATTACK
'UIDANCERADAR4HISISUSUALLYARADARONAMISSILETHATALLOWSTHEMISSILETO
hHOMEIN

147. vORGUIDEITSELF

148. TOATARGET
7EATHERMETEOROLOGICAL OBSERVATION3UCHRADARSDETECT

149. RECOGNIZE

150. ANDMEASURE
PRECIPITATION RATE

151. WIND SPEED AND DIRECTION

152. AND OBSERVE OTHER WEATHER EFFECTS
#OHERENTIMPLIESTHATTHEPHASEOFTHERADARSIGNALISUSEDASANIMPORTANTPARTOFTHERADARPROCESS

153. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°Ç
IMPORTANTFORMETEOROLOGICALPURPOSES4HESEMAYBESPECIALRADARSORANOTHER
FUNCTIONOFSURVEILLANCERADARS
$OPPLERWEATHERRADAR4HISISAWEATHEROBSERVATIONRADARTHATEMPLOYSTHEDOP
PLERFREQUENCYSHIFTCAUSEDBYMOVINGWEATHEREFFECTSTODETERMINETHEWINDTHE
WINDSHEARWHENTHEWINDBLOWSINDIFFERENTDIRECTIONS

154. WHICHCANINDICATEA
DANGEROUSWEATHERCONDITIONSUCHASATORNADOORADOWNBURSTOFWINDASWELLAS
OTHERMETEOROLOGICALEFFECTS
4ARGETRECOGNITION)NSOMECASES

155. ITMIGHTBEIMPORTANTTORECOGNIZETHETYPEOFTARGET
BEINGOBSERVEDBYRADAREG

156. ANAUTOMOBILERATHERTHANABIRD

157. ORTORECOGNIZETHEPAR
TICULARTYPEOFTARGETANAUTOMOBILERATHERTHANATRUCK

158. ORASTARLINGRATHERTHANASPAR
ROW

159. ORTORECOGNIZEONECLASSOFTARGETFROMANOTHERACRUISESHIPRATHERTHANATANKER
7HENUSEDFORMILITARYPURPOSES

160. ITISUSUALLYCALLEDANONCOOPERATIVETARGETRECOG
NITION.#42 RADAR

161. ASCOMPAREDTOACOOPERATIVERECOGNITIONSYSTEMSUCHAS)
IDENTIFICATIONFRIENDORFOE

162. WHICHISNOTARADAR7HENTARGETRECOGNITIONINVOLVES
SOMEPARTOFTHENATURALENVIRONMENT

163. THERADARISUSUALLYKNOWNASAREMOTESENS
INGOFTHEENVIRONMENT RADAR
-ULTIFUNCTIONRADAR)FEACHOFTHEABOVERADARSWERETHOUGHTOFASPROVIDINGSOME
RADARFUNCTION

164. THENAMULTIFUNCTIONRADARISONEDESIGNEDTOPERFORMMORETHANONE
SUCHFUNCTIONˆUSUALLYPERFORMINGONEFUNCTIONATATIMEONATIME
SHAREDBASIS
4HEREAREMANYOTHERWAYSTODESCRIBERADARS

165. INCLUDINGLAND

166. SEA

167. AIRBORNE

168. SPACE
BORNE

169. MOBILE

170. TRANSPORTABLE

171. AIR
TRAFFICCONTROL

172. MILITARY

173. GROUND
PENETRATING

174. ULTRA
WIDEBAND

175. OVERTHEHORIZON

176. INSTRUMENTATION

177. LASERORLIDAR

178. BYTHEFREQUENCYBANDAT
WHICHTHEYOPERATE5(

179. ,

180. 3

181. ANDSOON

182. BYTHEIRAPPLICATION

183. ANDSOFORTH
£°ÎÊ ,/ Ê6
Ê,ÊÊ,

184. ,
$ETECTIONOFTARGETSISOFLITTLEVALUEUNLESSSOMEINFORMATIONABOUTTHETARGETISOBTAINED
ASWELL,IKEWISE

185. TARGETINFORMATIONWITHOUTTARGETDETECTIONISMEANINGLESS
2ANGE 0ROBABLYTHEMOSTDISTINGUISHINGFEATUREOFACONVENTIONALRADARISITSABILITY
TODETERMINETHERANGETOATARGETBYMEASURINGTHETIMEITTAKESFORTHERADARSIGNALTO
PROPAGATEATTHESPEEDOFLIGHTOUTTOTHETARGETANDBACKTOTHERADAR.OOTHERSENSORCAN
MEASURETHEDISTANCETOAREMOTETARGETATLONGRANGEWITHTHEACCURACYOFRADARBASICALLY
LIMITEDATLONGRANGESBYTHEACCURACYOFTHEKNOWLEDGEOFTHEVELOCITYOFPROPAGATION
!TMODESTRANGES

186. THEPRECISIONCANBEAFEWCENTIMETERS4OMEASURERANGE

187. SOMESORT
OFTIMINGMARKMUSTBEINTRODUCEDONTHETRANSMITTEDWAVEFORM!TIMINGMARKCAN
BEASHORTPULSEANAMPLITUDEMODULATIONOFTHESIGNAL

188. BUTITCANALSOBEADISTINCTIVE
MODULATIONOFTHEFREQUENCYORPHASE4HEACCURACYOFARANGEMEASUREMENTDEPENDS
ONTHERADARSIGNALBANDWIDTHTHEWIDERTHEBANDWIDTH

189. THEGREATERTHEACCURACY4HUS
BANDWIDTHISTHEBASICMEASUREOFRANGEACCURACY
2ADIAL6ELOCITY 4HERADIALVELOCITYOFATARGETISOBTAINEDFROMTHERATEOFCHANGE
OFRANGEOVERAPERIODOFTIME)TCANALSOBEOBTAINEDFROMTHEMEASUREMENTOFTHEDOP
PLERFREQUENCYSHIFT!NACCURATEMEASUREMENTOFRADIALVELOCITYREQUIRESTIME(ENCE
TIMEISTHEBASICPARAMETERDESCRIBINGTHEQUALITYOFARADIALVELOCITYMEASUREMENT4HE
SPEEDOFAMOVINGTARGETANDITSDIRECTIONOFTRAVELCANBEOBTAINEDFROMITSTRACK

190. WHICH
CANBEFOUNDFROMTHERADARMEASUREMENTSOFTHETARGETLOCATIONOVERAPERIODOFTIME

191. £°n 2!$!2(!.$//+
!NGULAR$IRECTION /NEMETHODFORDETERMININGTHEDIRECTIONTOATARGETISBY
DETERMININGTHEANGLEWHERETHEMAGNITUDEOFTHEECHOSIGNALFROMASCANNINGANTENNA
ISMAXIMUM4HISUSUALLYREQUIRESANANTENNAWITHANARROWBEAMWIDTHAHIGH
GAIN
ANTENNA !NAIR
SURVEILLANCERADARWITHAROTATINGANTENNABEAMDETERMINESANGLEIN
THISMANNER4HEANGLETOATARGETINONEANGULARDIMENSIONCANALSOBEDETERMINEDBY
USINGTWOANTENNABEAMS

192. SLIGHTLYDISPLACEDINANGLE

193. ANDCOMPARINGTHEECHOAMPLI
TUDERECEIVEDINEACHBEAMOURBEAMSARENEEDEDTOOBTAINTHEANGLEMEASUREMENT
INBOTHAZIMUTHANDELEVATION4HEMONOPULSETRACKINGRADARDISCUSSEDIN#HAPTERIS
AGOODEXAMPLE4HEACCURACYOFANANGLEMEASUREMENTDEPENDSONTHEELECTRICALSIZE
OFTHEANTENNAIE

194. THESIZEOFTHEANTENNAGIVENINWAVELENGTHS
3IZEAND3HAPE )FTHERADARHASSUFFICIENTRESOLUTIONCAPABILITYINRANGEORANGLE

195. ITCANPROVIDEAMEASUREMENTOFTHETARGETEXTENTINTHEDIMENSIONOFHIGHRESOLU
TION2ANGEISUSUALLYTHECOORDINATEWHERERESOLUTIONISOBTAINED2ESOLUTIONINCROSS
RANGEGIVENBYTHERANGEMULTIPLIEDBYTHEANTENNABEAMWIDTH CANBEOBTAINEDWITH
VERYNARROWBEAMWIDTHANTENNAS(OWEVER

196. THEANGULARWIDTHOFANANTENNABEAMIS
LIMITED

197. SOTHECROSS
RANGERESOLUTIONOBTAINEDBYTHISMETHODISNOTASGOODASTHE
RANGERESOLUTION6ERYGOODRESOLUTIONINTHECROSS
RANGEDIMENSIONCANBEOBTAINED
BYEMPLOYINGTHEDOPPLERFREQUENCYDOMAIN

198. BASEDON3!2SYNTHETICAPERTURERADAR
OR)3!2INVERSESYNTHETICAPERTURERADARSYSTEMS

199. ASDISCUSSEDIN#HAPTER4HERE
NEEDSTOBERELATIVEMOTIONBETWEENTHETARGETANDTHERADARINORDERTOOBTAINTHE
CROSS
RANGERESOLUTIONBY3!2OR)3!27ITHSUFFICIENTRESOLUTIONINBOTHRANGEAND
CROSS
RANGE

200. NOTONLYCANTHESIZEBEOBTAINEDINTWOORTHOGONALCOORDINATES

201. BUTTHE
TARGETSHAPECANSOMETIMESBEDISCERNED
4HE)MPORTANCEOFANDWIDTHIN2ADAR ANDWIDTHBASICALLYREPRESENTSINFOR
MATIONHENCE

202. ITISVERYIMPORTANTINMANYRADARAPPLICATIONS4HEREARETWOTYPESOF
BANDWIDTHENCOUNTEREDINRADAR/NEISTHESIGNALBANDWIDTH

203. WHICHISTHEBANDWIDTH
DETERMINEDBYTHESIGNALPULSEWIDTHORBYANYINTERNALMODULATIONOFTHESIGNAL4HE
OTHERISTUNABLEBANDWIDTH'ENERALLY

204. THESIGNALBANDWIDTHOFASIMPLEPULSEOFSINE
WAVEOFDURATIONSISS0ULSECOMPRESSIONWAVEFORMS

205. DISCUSSEDIN#HAPTER

206. CAN
HAVEMUCHGREATERBANDWIDTHTHANTHERECIPROCALOFTHEIRPULSEWIDTH ,ARGEBAND
WIDTHISNEEDEDFORRESOLVINGTARGETSINRANGE

207. FORACCURATEMEASUREMENTOFRANGETO
ATARGET

208. ANDFORPROVIDINGALIMITEDCAPABILITYTORECOGNIZEONETYPEOFTARGETFROM
ANOTHER(IGHRANGERESOLUTIONALSOCANBEUSEFULFORREDUCINGTHEDEGRADINGEFFECTS
OFWHATISKNOWNASGLINTINATRACKINGRADAR

209. FORMEASURINGTHEALTITUDEOFANAIRCRAFT
BASEDONTHEDIFFERENCEINTIMEDELAYRANGE BETWEENTHETWO
WAYDIRECTSIGNALFROM
RADARTOTARGETANDTHETWO
WAYSURFACE
SCATTEREDSIGNALFROMRADARTOSURFACETOTARGET
ALSOCALLEDMULTIPATHHEIGHTFINDING

210. ANDININCREASINGTHETARGET
SIGNAL
TO
CLUTTER
RATIO)NMILITARYSYSTEMS

211. HIGHRANGERESOLUTIONMAYBEEMPLOYEDFORCOUNTINGTHE
NUMBEROFAIRCRAFTFLYINGINCLOSEFORMATIONANDFORRECOGNIZINGANDTHWARTINGSOME
TYPESOFDECEPTIONCOUNTERMEASURES
4UNABLEBANDWIDTHOFFERSTHEABILITYTOCHANGETUNE THERADARSIGNALFREQUENCY
OVERAWIDERANGEOFTHEAVAILABLESPECTRUM4HISCANBEUSEDFORREDUCINGMUTUALINTER
FERENCEAMONGRADARSTHATOPERATEINTHESAMEFREQUENCYBAND

212. ASWELLASINATTEMPTING
TOMAKEHOSTILEELECTRONICCOUNTERMEASURESLESSEFFECTIVE4HEHIGHERTHEOPERATING
FREQUENCYTHEEASIERITISTOOBTAINWIDESIGNALANDWIDETUNABLEBANDWIDTH
!LIMITATIONONTHEAVAILABILITYOFBANDWIDTHINARADARISTHECONTROLOFTHESPECTRUM
BYGOVERNMENTREGULATINGAGENCIESINTHE5NITED3TATES

213. THEEDERAL#OMMUNICATION

214. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°™
#OMMISSION

215. ANDINTERNATIONALLY

216. THE)NTERNATIONAL4ELECOMMUNICATIONS5NION !FTER
THESUCCESSOFRADARIN7ORLD7AR))

217. RADARWASALLOWEDTOOPERATEOVERABOUTONE
THIRDOFTHEMICROWAVESPECTRUM4HISSPECTRUMSPACEHASBEENREDUCEDCONSIDERABLY
OVERTHEYEARSWITHTHEADVENTOFMANYCOMMERCIALUSERSOFTHESPECTRUMINTHEAGEOF
hWIRELESSvANDOTHERSERVICESREQUIRINGTHEELECTROMAGNETICSPECTRUM4HUS

218. THERADAR
ENGINEERISINCREASINGLYEXPERIENCINGSMALLERAVAILABLESPECTRUMSPACEANDBANDWIDTH
ALLOCATIONSTHATCANBEVITALFORTHESUCCESSOFMANYRADARAPPLICATIONS
3IGNAL
TO
.OISE2ATIO 4HEACCURACYOFALLRADARMEASUREMENTS

219. ASWELLASTHE
RELIABLEDETECTIONOFTARGETSDEPENDSONTHERATIO%.O

220. WHERE%ISTHETOTALENERGY
OFTHERECEIVEDSIGNALTHATISPROCESSEDBYTHERADARAND.OISTHENOISEPOWERPER
UNITBANDWIDTHOFTHERECEIVER4HUS%.OISANIMPORTANTMEASUREOFTHECAPABILITY
OFARADAR
/PERATIONWITH-ORE4HAN/NEREQUENCY 4HEREMAYBEIMPORTANTBENEFITS
WHENARADARISABLETOOPERATEATMORETHANONEFREQUENCY
REQUENCYAGILITYUSUALLY
REFERSTOTHEUSEOFMULTIPLEFREQUENCIESONAPULSE
TO
PULSEBASISREQUENCYDIVERSITY
USUALLYRELATESTOTHEUSEOFMULTIPLEFREQUENCIESTHATAREWIDELYSEPARATED

221. SOMETIMESIN
MORETHANONERADARBANDREQUENCYDIVERSITYMIGHTOPERATEATEACHFREQUENCYSIMUL
TANEOUSLYORALMOSTSIMULTANEOUSLY)THASBEENUSEDINALMOSTALLCIVILIANAIR
TRAFFIC
CONTROLRADARS0ULSE
TO
PULSEFREQUENCYAGILITY

222. HOWEVER

223. ISNOTCOMPATIBLEWITHTHEUSE
OFDOPPLERPROCESSINGTODETECTMOVINGTARGETSINCLUTTER

224. BUTFREQUENCYDIVERSITYCAN
BECOMPATIBLE4HEFREQUENCYRANGEINBOTHAGILITYANDINDIVERSITYOPERATIONSISMUCH
GREATERTHANTHEINHERENTBANDWIDTHOFAPULSEOFWIDTHS
%LEVATION.ULLILLING /PERATIONOFARADARATASINGLEFREQUENCYCANRESULTINA
LOBEDSTRUCTURETOTHEELEVATIONPATTERNOFANANTENNADUETOTHEINTERFERENCEBETWEEN
THEDIRECTSIGNALRADARTOTARGET ANDTHESURFACE
SCATTEREDSIGNALRADARTOEARTHSSUR
FACETOTARGET YALOBEDSTRUCTURE

225. WEMEANTHATTHEREWILLBEREDUCEDCOVERAGEAT
SOMEELEVATIONANGLESNULLS ANDINCREASEDSIGNALSTRENGTHATOTHERANGLESLOBES !
CHANGEINFREQUENCYWILLCHANGETHELOCATIONOFTHENULLSANDLOBESSOTHATBYOPERATING
OVERAWIDEFREQUENCYRANGE

226. THENULLSINELEVATIONCANBEFILLEDIN

227. ANDTHERADARWILL
BELESSLIKELYTOLOSEATARGETECHOSIGNALOREXAMPLE

228. MEASUREMENTSWITHAWIDEBAND
EXPERIMENTALRADARKNOWNAS3ENRAD

229. WHICHCOULDOPERATEFROMTO-(Z

230. SHOWEDTHATWHENONLYASINGLEFREQUENCYWASUSED

231. THEBLIP
SCANRATIOTHEEXPERI
MENTALLYMEASUREDSINGLE
SCANPROBABILITYOFDETECTION WASFOUNDTOBEUNDERA
PARTICULARSETOFOBSERVATIONS7HENTHERADAROPERATEDATFOURDIFFERENTWIDELYSEPA
RATEDFREQUENCIES

232. THEBLIP
SCANRATIOWASˆAHIGHLYSIGNIFICANTINCREASEDUETO
FREQUENCYDIVERSITY
)NCREASED4ARGET$ETECTABILITY 4HERADARCROSSSECTIONOFACOMPLEXTARGETSUCH
ASANAIRCRAFTCANVARYGREATLYWITHACHANGEINFREQUENCY!TSOMEFREQUENCIES

233. THE
RADARCROSSSECTIONWILLBESMALLANDATOTHERSITWILLBELARGE)FARADAROPERATESATA
SINGLEFREQUENCY

234. ITMIGHTRESULTINASMALLTARGETECHOAND

235. THEREFORE

236. AMISSEDDETEC
TIONYOPERATINGATANUMBEROFDIFFERENTFREQUENCIES

237. THECROSSSECTIONWILLVARYAND
CANBESMALLORLARGEBUTASUCCESSFULDETECTIONBECOMESMORELIKELYTHANIFONLYA
SINGLEFREQUENCYWEREUSED4HISISONEREASONTHATALMOSTALLAIR
TRAFFICCONTROLRADARS
OPERATEWITHTWOFREQUENCIESSPACEDWIDEENOUGHAPARTINFREQUENCYTOINSURETHAT
TARGETECHOESAREDECORRELATEDAND

238. THEREFORE

239. INCREASETHELIKELIHOODOFDETECTION

240. £°£ä 2!$!2(!.$//+
2EDUCED%FFECTIVENESSOF(OSTILE#OUNTERMEASURES !NYMILITARYRADARTHATISSUC
CESSFULCANEXPECTAHOSTILEADVERSARYTOEMPLOYCOUNTERMEASURESTOREDUCEITSEFFEC
TIVENESS/PERATINGOVERAWIDERANGEOFFREQUENCIESMAKESCOUNTERMEASURESMORE
DIFFICULTTHANIFOPERATIONISATONLYONEFREQUENCY!GAINSTNOISEJAMMING

241. CHANGING
FREQUENCYINANUNPREDICTABLEMANNEROVERAWIDERANGEOFFREQUENCIESCAUSESTHEJAM
MERTOHAVETOSPREADITSPOWEROVERAWIDEFREQUENCYRANGEANDWILL

242. THEREFORE

243. REDUCE
THEHOSTILEJAMMINGSIGNALSTRENGTHOVERTHEBANDWIDTHOFTHERADARSIGNALREQUENCY
DIVERSITYOVERAWIDEBANDALSOMAKESITMOREDIFFICULTBUTNOTIMPOSSIBLE FORAHOSTILE
INTERCEPTRECEIVERORANANTIRADIATIONMISSILETODETECTANDLOCATEARADARSIGNAL
4HE$OPPLER3HIFTIN2ADAR 4HEIMPORTANCEOFTHEDOPPLERFREQUENCYSHIFT
BEGANTOBEAPPRECIATEDFORPULSERADARSHORTLYAFTER7ORLD7AR))ANDBECAMEAN
INCREASINGLY IMPORTANT FACTOR IN MANY RADAR APPLICATIONS -ODERN RADAR WOULD BE
MUCHLESSINTERESTINGORUSEFULIFTHEDOPPLEREFFECTDIDNTEXIST4HEDOPPLERFREQUENCY
SHIFTFDCANBEWRITTENAS
F V V
D R
COS
L Q L
WHEREVRVCOSPISTHERELATIVEVELOCITYOFTHETARGETRELATIVETOTHERADAR INMS

244. VIS
THEABSOLUTEVELOCITYOFTHETARGETINMS

245. KISTHERADARWAVELENGTHINM

246. ANDPISTHE
ANGLEBETWEENTHETARGETSDIRECTIONANDTHERADARBEAM4OANACCURACYOFABOUTPER
CENT

247. THEDOPPLERFREQUENCYINHERTZISAPPROXIMATELYEQUALTOVRKT DIVIDEDBYKM
4HE DOPPLER FREQUENCY SHIFT IS WIDELY USED TO SEPARATE MOVING TARGETS FROM
STATIONARYCLUTTER

248. ASDISCUSSEDIN#HAPTERSTHROUGH3UCHRADARSAREKNOWNAS-4)
MOVINGTARGETINDICATION

249. !-4)AIRBORNE-4)

250. ANDPULSEDOPPLER!LLMODERNAIR
TRAFFICCONTROLRADARS

251. ALLIMPORTANTMILITARYGROUND
BASEDANDAIRBORNEAIR
SURVEILLANCE
RADARS

252. ANDALLMILITARYAIRBORNEFIGHTERRADARSTAKEADVANTAGEOFTHEDOPPLEREFFECT9ETIN
77))

253. NONEOFTHESEPULSERADARAPPLICATIONSUSEDDOPPLER4HE#7CONTINUOUSWAVE
RADARALSOEMPLOYSTHEDOPPLEREFFECTFORDETECTINGMOVINGTARGETS

254. BUT#7RADARFOR
THISPURPOSEISNOTASPOPULARASITONCEWAS4HE(/4(RADAR#HAPTER COULDNOT
DOITSJOBOFDETECTINGMOVINGTARGETSINTHEPRESENCEOFLARGECLUTTERECHOESFROMTHE
EARTHSSURFACEWITHOUTTHEUSEOFDOPPLER
!NOTHERSIGNIFICANTAPPLICATIONOFRADARTHATDEPENDSONTHEDOPPLERSHIFTISOBSER
VATIONOFTHEWEATHER

255. ASINTHE.EXRADRADARSOFTHE53.ATIONAL7EATHER3ERVICE
#HAPTER MENTIONEDEARLIERINTHISCHAPTER
OTHTHE3!2AND)3!2CANBEDESCRIBEDINTERMSOFTHEIRUSEOFTHEDOPPLERFRE
QUENCYSHIFT#HAPTER 4HEAIRBORNEDOPPLERNAVIGATORRADARISALSOBASEDONTHE
DOPPLERSHIFT4HEUSEOFDOPPLERINARADARGENERALLYPLACESGREATERDEMANDSONTHE
STABILITYOFTHERADARTRANSMITTER

256. ANDITINCREASESTHECOMPLEXITYOFTHESIGNALPROCESS
INGYETTHESEREQUIREMENTSAREWILLINGLYACCEPTEDINORDERTOACHIEVETHESIGNIFICANT
BENEFITSOFFEREDBYDOPPLER)TSHOULDALSOBEMENTIONEDTHATTHEDOPPLERSHIFTISTHEKEY
CAPABILITYOFARADARTHATCANMEASURESPEED

257. ASBYITSDILIGENTUSEBYTRAFFICPOLICEFOR
MAINTAININGVEHICLESPEEDLIMITSANDINOTHERVELOCITYMEASURINGAPPLICATIONS
£°{Ê /
Ê,

258. ,Ê
+1/
4HERADARRANGEEQUATIONORRADAREQUATION

259. FORSHORT NOTONLYSERVESTHEVERYUSEFUL
PURPOSEOFESTIMATINGTHERANGEOFARADARASAFUNCTIONOFTHERADARCHARACTERISTICS

261. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°££
BUTALSOISQUITEUSEFULASAGUIDEFORDESIGNINGARADARSYSTEM4HESIMPLEFORMOFTHE
RADAREQUATIONMAYBEWRITTENAS
0
0 '
2 2
!
R
T T
E
r r
P
S
P
4HERIGHT
HANDSIDEHASBEENWRITTENASTHEPRODUCTOFTHREEFACTORSTOREPRESENTTHE
PHYSICALPROCESSESTHATTAKEPLACE4HEFIRSTFACTORONTHERIGHTISTHEPOWERDENSITY
ATADISTANCE2FROMARADARTHATRADIATESAPOWER0TFROMANANTENNAOFGAIN'T4HE
NUMERATOR

262. R

263. OFTHESECONDFACTORISTHERADARCROSSSECTIONOFTHETARGET)THASTHEUNIT
OFAREAFOREXAMPLE

264. SQUAREMETERS ANDISAMEASUREOFTHEENERGYREDIRECTEDBYTHE
TARGETBACKINTHEDIRECTIONOFTHERADAR4HEDENOMINATOROFTHESECONDFACTORACCOUNTS
FORTHEDIVERGENCEOFTHEECHOSIGNALONITSRETURNPATHBACKTOTHERADAR4HEPRODUCT
OFTHEFIRSTTWOFACTORSREPRESENTSTHEPOWERPERUNITAREARETURNEDTOTHERADARANTENNA
.OTETHATTHERADARCROSSSECTIONOFATARGET

265. R

266. ISDEFINEDBYTHISEQUATION4HERECEIVING
ANTENNAOFEFFECTIVEAREA!ECOLLECTSAPORTION0ROFTHEECHOPOWERRETURNEDTOTHERADAR
)FTHEMAXIMUMRADARRANGE

267. 2MAX

268. ISDEFINEDASOCCURRINGWHENTHERECEIVEDSIGNALIS
EQUALTOTHEMINIMUMDETECTABLESIGNALOFTHERADAR

269. 3MIN

270. THESIMPLEFORMOFTHERADAR
EQUATIONBECOMES
2
0 ' !
3
T T E
MAX
MIN
S
P
'ENERALLY

271. MOSTRADARSUSETHESAMEANTENNAFORBOTHTRANSMITTINGANDRECEIVINGROM
ANTENNATHEORY

272. THEREISARELATIONBETWEENTHEGAIN'TOFTHEANTENNAONTRANSMITAND
ITSEFFECTIVEAREA!EONRECEIVE

273. WHICHIS' !
T E
P L

274. WHEREKISTHEWAVELENGTHOF
THERADARSIGNAL3UBSTITUTINGTHISINTO%QPROVIDESTWOOTHERUSEFULFORMSOFTHE
RADAREQUATIONNOTSHOWNHERE ONETHATREPRESENTSTHEANTENNAONLYBYITSGAINAND
THEOTHERTHATREPRESENTSTHEANTENNAONLYBYITSEFFECTIVEAREA
4HESIMPLEFORMOFTHERADAREQUATIONISINSTRUCTIVE

275. BUTNOTVERYUSEFULSINCEIT
LEAVESOUTMANYTHINGS4HEMINIMUMDETECTABLESIGNAL

276. 3MIN

277. ISLIMITEDBYRECEIVER
NOISEANDCANBEEXPRESSEDAS
3 K4 3 .
O N
MIN
)NTHISEXPRESSION

278. K4OISTHESO
CALLEDTHERMALNOISEFROMANIDEALOHMICCONDUC
TOR

279. WHEREKOLTZMANNSCONSTANT

280. 4OISTHESTANDARDTEMPERATUREOF+

281. AND
RECEIVERBANDWIDTHUSUALLYTHATOFTHE)STAGEOFTHESUPERHETERODYNERECEIVER 4HE
PRODUCTK4OISEQUALTOr
7(Z4OACCOUNTFORTHEADDITIONALNOISEINTRODUCED
BYAPRACTICALNONIDEAL RECEIVER

282. THETHERMALNOISEEXPRESSIONISMULTIPLIEDBYTHE
NOISEFIGURENOFTHERECEIVER

283. DEFINEDASTHENOISEOUTOFAPRACTICALRECEIVERTOTHE
NOISEOUTOFANIDEALRECEIVERORARECEIVEDSIGNALTOBEDETECTABLE

284. ITHASTOBELARGER
THANTHERECEIVERNOISEBYAFACTORDENOTEDHEREAS3. 4HISVALUEOFSIGNAL
TO
NOISERATIO3. ISTHATREQUIREDIFONLYONEPULSEISPRESENT)THASTOBELARGEENOUGH
TOOBTAINTHEREQUIREDPROBABILITYOFFALSEALARMDUETONOISECROSSINGTHERECEIVER
THRESHOLD ANDTHEREQUIREDPROBABILITYOFDETECTIONASCANBEFOUNDINVARIOUSRADAR
TEXTS

285. 2ADARS

286. HOWEVER

287. GENERALLYPROCESSMORETHANONEPULSEBEFOREMAKINGA
DETECTIONDECISION7EASSUMETHERADARWAVEFORMISAREPETITIVESERIESOFRECTANGULAR
LIKEPULSES4HESEPULSESAREINTEGRATEDADDEDTOGETHER BEFOREADETECTIONDECISION

288. £°£Ó 2!$!2(!.$//+
ISMADE4OACCOUNTFORTHESEADDEDSIGNALS

289. THENUMERATOROFTHERADAREQUATIONIS
MULTIPLIEDBYAFACTORN%IN

290. WHERE%IN ISTHEEFFICIENCYINADDINGTOGETHERNPULSES
4HISVALUECANALSOBEFOUNDINSTANDARDTEXTS
4HEPOWER0TISTHEPEAKPOWEROFARADARPULSE4HEAVERAGEPOWER

291. 0AV

292. ISABETTER
MEASUREOFTHEABILITYOFARADARTODETECTTARGETS

293. SOITISSOMETIMESINSERTEDINTOTHE
RADAREQUATIONUSING0T0AVFPS

294. WHEREFPISTHEPULSEREPETITIONFREQUENCYOFTHEPULSE
RADARANDSISTHEPULSEDURATION4HESURFACEOFTHEEARTHANDTHEEARTHSATMOSPHERECAN
DRASTICALLYAFFECTTHEPROPAGATIONOFELECTROMAGNETICWAVESANDCHANGETHECOVERAGEAND
CAPABILITIESOFARADAR)NTHERADAREQUATION

295. THESEPROPAGATIONEFFECTSAREACCOUNTEDFOR
BYAFACTOR
INTHENUMERATOROFTHERADAREQUATION

296. ASDISCUSSEDIN#HAPTER7ITH
THEABOVESUBSTITUTEDINTOTHESIMPLEFORMOFTHERADAREQUATIONWEGET
2
0 '! N% N
K4 F 3 . ,
E I
O N P S
MAX
AV S
P
)NTHEABOVEEQUATION

297. ITWASASSUMEDINITSDERIVATIONTHATSy

298. WHICHISGENERALLY
APPLICABLEINRADAR!FACTOR,SGREATERTHANUNITY

299. CALLEDTHESYSTEMLOSSES

300. HASBEEN
INSERTEDTOACCOUNTFORTHEMANYWAYSTHATLOSSCANOCCURINARADAR4HISLOSSFACTOR
CANBEQUITELARGE)FTHESYSTEMLOSSISIGNORED

301. ITMIGHTRESULTINAVERYLARGEERRORIN
THEESTIMATEDRANGEPREDICTEDBYTHERADAREQUATION!LOSSOFFROMDTOMAYBE
DISNOTUNUSUALWHENALLRADARSYSTEMLOSSFACTORSARETAKENINTOACCOUNT
%QUATIONAPPLIESFORARADARTHATOBSERVESATARGETLONGENOUGHTORECEIVEN
PULSES-OREFUNDAMENTALLY

302. ITAPPLIESFORARADARWHERETHETIMEONTARGETTOISEQUAL
TONFP!NEXAMPLEISATRACKINGRADARTHATCONTINUOUSLYOBSERVESASINGLETARGETFOR
ATIMETO4HISEQUATION

303. HOWEVER

304. NEEDSTOBEMODIFIEDFORASURVEILLANCERADARTHAT
OBSERVESANANGULARVOLUME7WITHAREVISITTIMETS!IRTRAFFICCONTROLRADARSMIGHT
HAVEAREVISITTIMEOFFROMTOS 4HUS

305. ASURVEILLANCERADARHASTHEADDITIONAL
CONSTRAINT THAT IT MUST COVER AN ANGULAR VOLUME 7 IN A GIVEN TIME TS4HE REVISIT
TIMETSISEQUALTOTO77O

306. WHERETONFPAND7O

307. THESOLIDBEAMWIDTHOFTHEANTENNA
STERADIANS

308. ISAPPROXIMATELYRELATEDTOTHEANTENNAGAIN'BY'O7O4HEREFORE

309. WHENNFPIN%QISREPLACEDWITHITSEQUALOTS'7

310. THERADAREQUATIONFORA
SURVEILLANCERADARISOBTAINEDAS
2
0 ! % N
K4 3 . ,
T
E I
O N S
S
MAX
r
AV S
P 7
4HERADARDESIGNERHASLITTLECONTROLOVERTHEREVISITTIMETSORTHEANGULARCOVERAGE
7

311. WHICHAREDETERMINEDMAINLYBYTHEJOBTHERADARHASTOPERFORM4HERADARCROSS
SECTIONALSOISDETERMINEDBYTHERADARAPPLICATION)FALARGERANGEISREQUIREDOF
ASURVEILLANCERADAR

312. THERADARMUSTHAVETHENECESSARYVALUEOFTHEPRODUCT0AV!E
ORTHISREASON

313. ACOMMONMEASUREOFTHECAPABILITYOFASURVEILLANCERADARISITS
POWER
APERTUREPRODUCT.OTETHATTHERADARFREQUENCYDOESNOTAPPEAREXPLICITLY
INTHESURVEILLANCERADAREQUATION4HECHOICEOFFREQUENCY

314. HOWEVER

315. WILLENTER
IMPLICITLYINOTHERWAYS
*USTASTHERADAREQUATIONFORASURVEILLANCERADARISDIFFERENTFROMTHECONVENTIONAL
RADAREQUATIONOF%QORTHESIMPLERADAREQUATIONOF%Q

316. EACHPARTICULARAPPLICA
TIONOFARADARGENERALLYHASTOEMPLOYARADAREQUATIONTAILOREDTOTHATSPECIFICAPPLICA
TION7HENTHERADARECHOESFROMLAND

317. SEA

318. ORWEATHERCLUTTERAREGREATERTHANTHERECEIVER
NOISE

319. THERADAREQUATIONHASTOBEMODIFIEDTOACCOUNTFORCLUTTERBEINGTHELIMITATIONTO

320. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°£Î
DETECTIONRATHERTHANRECEIVERNOISE)TCANHAPPENTHATTHEDETECTIONCAPABILITYOFARADAR
MIGHTBELIMITEDBYCLUTTERINSOMEREGIONSOFITSCOVERAGEANDBELIMITEDBYRECEIVER
NOISEINOTHERREGIONS4HISCANRESULTINTWODIFFERENTSETSOFRADARCHARACTERISTICS

321. ONE
OPTIMIZEDFORNOISEANDTHEOTHEROPTIMIZEDFORCLUTTERANDCOMPROMISESUSUALLYHAVETO
BEMADEINRADARDESIGN!DIFFERENTTYPEOFRADAREQUATIONISALSOREQUIREDWHENTHERADAR
CAPABILITYISLIMITEDBYHOSTILENOISEJAMMING
£°xÊ ,

322. ,Ê,
+1
9Ê
//
,‡

323. Ê
/1,
)TISNOTALWAYSCONVENIENTTOUSETHEEXACTNUMERICALFREQUENCYRANGEOVERWHICHA
PARTICULARTYPEOFRADAROPERATES7ITHMANYMILITARYRADARS

324. THEEXACTOPERATINGFRE
QUENCYRANGEOFARADARISUSUALLYNOTDISCLOSED4HUS

325. THEUSEOFLETTERSTODESIGNATE
RADAROPERATINGBANDSHASBEENVERYHELPFUL4HE)%%%)NSTITUTEOF%LECTRICALAND
%LECTRONIC%NGINEERS HASOFFICIALLYSTANDARDIZEDTHERADARLETTER
BANDNOMENCLATURE

326. ASSUMMARIZEDIN4ABLE
#OMMENTS ON THE TABLE
4HE )NTERNATIONAL 4ELECOMMUNICATIONS 5NION )45
ASSIGNS SPECIFIC PORTIONS OF THE ELECTROMAGNETIC SPECTRUM FOR RADIOLOCATION RADAR
USEASSHOWNINTHETHIRDCOLUMN

327. WHICHAPPLIESTO)452EGIONTHATINCLUDES.ORTH
AND3OUTH!MERICA3LIGHTDIFFERENCESOCCURINTHEOTHERTWO)452EGIONS4HUSAN
,
BANDRADARCANONLYOPERATEWITHINTHEFREQUENCYRANGEFROM-(ZTO-(Z

328. ANDEVENWITHINTHISRANGE

329. THEREMAYBERESTRICTIONS3OMEOFTHEINDICATED)45BANDS
ARERESTRICTEDINTHEIRUSAGEFOREXAMPLE

330. THEBANDBETWEENAND'(ZISRESERVED
AND$ESIGNATION .OMINALREQUENCY2ANGE
3PECIFICREQUENCY2ANGESFOR2ADARASED
ON)45REQUENCY!SSIGNMENTS
FOR2EGION
( -(Zn-(Z
6( n-(Z n-(Z
n-(Z
5( n-(Z n-(Z
n-(Z
, n'(Z n-(Z
3 n'(Z n'(Z
n'(Z
# n'(Z n'(Z
n'(Z
8 n'(Z n'(Z
+U n'(Z n'(Z
n'(Z
+ n'(Z n'(Z
n'(Z
+A n'(Z n'(Z
6 n'(Z n'(Z
7 n'(Z n'(Z
n'(Z
4!,% )%%%3TANDARD,ETTER$ESIGNATIONSFOR2ADAR
REQUENCYANDS

331. £°£{ 2!$!2(!.$//+
WITHFEWEXCEPTIONS FORAIRBORNERADARALTIMETERS4HEREARENOOFFICIAL)45ALLOCATIONS
FORRADARINTHE(BAND

332. BUTMOST(RADARSSHAREFREQUENCIESWITHOTHERELECTROMAG
NETICSERVICES4HELETTER
BANDDESIGNATIONFORMILLIMETERWAVERADARSISMM

333. ANDTHERE
ARESEVERALFREQUENCYBANDSALLOCATEDTORADARINTHISREGION

334. BUTTHEYHAVENOTBEEN
LISTEDHERE!LTHOUGHTHEOFFICIAL)45DESCRIPTIONOFMILLIMETERWAVESISFROMTO
'(Z

335. INREALITY

336. THETECHNOLOGYOFRADARSAT+ABAND
ISMUCHCLOSERTOTHETECHNOLOGY
OFMICROWAVEFREQUENCIESTHANTOTHETECHNOLOGYOF7BAND4HEMILLIMETERWAVERADAR
FREQUENCIESAREOFTENCONSIDEREDBYTHOSEWHOWORKINTHISFIELDTOHAVEALOWERBOUND
OF'(ZRATHERTHANTHEhLEGALvLOWERBOUNDOF'(ZINRECOGNITIONOFTHESIGNIFICANT
DIFFERENCEINTECHNOLOGYANDAPPLICATIONSTHATISCHARACTERISTICOFMILLIMETERWAVERADAR
-ICROWAVESHAVENOTBEENDEFINEDINTHISSTANDARD

337. BUTTHISTERMGENERALLYAPPLIESTO
RADARSTHATOPERATEFROM5(TO+ABAND4HEREASONTHATTHESELETTERDESIGNATIONSMIGHT
NOTBEEASYFORTHENON
RADARENGINEERTORECOGNIZEISTHATTHEYWEREORIGINALLYSELECTED
TODESCRIBETHERADARBANDSUSEDIN7ORLD7AR))3ECRECYWASIMPORTANTATTHATTIMESO
THELETTERSSELECTEDTODESIGNATETHEVARIOUSBANDSMADEITHARDTOGUESSTHEFREQUENCIES
TOWHICHTHEYAPPLY4HOSEWHOWORKAROUNDRADAR

338. HOWEVER

339. SELDOMHAVEAPROBLEM
WITHTHEUSAGEOFTHERADARLETTERBANDS
/THERLETTERBANDSHAVEBEENUSEDFORDESCRIBINGTHEELECTROMAGNETICSPECTRUMBUT
THEYARENOTSUITABLEFORRADARANDSHOULDNEVERBEUSEDFORRADAR/NESUCHDESIGNATION
USESTHELETTERS!

340. #

341. ETC

342. ORIGINALLYDEVISEDFORCONDUCTINGELECTRONICCOUNTERMEASURE
EXERCISES
4HE)%%%3TANDARDMENTIONEDPREVIOUSLYSTATESTHATTHESEhARENOTCONSISTENT
WITHRADARPRACTICEANDSHALLNOTBEUSEDTODESCRIBERADAR
FREQUENCYBANDSv4HUS

343. THERE
MAYBE$
BANDJAMMERS

344. BUTNEVER$
BANDRADARS
£°ÈÊ
/ÊÊ*
,/ ÊÊ
,
+1
9Ê Ê,

345. ,
2ADARSHAVEBEENOPERATEDATFREQUENCIESASLOWAS-(ZJUSTABOVETHE!-BROAD
CASTBAND ANDASHIGHASSEVERALHUNDRED'(ZMILLIMETERWAVEREGION -OREUSU
ALLY

346. RADARFREQUENCIESMIGHTBEFROMABOUT-(ZTOOVER'(Z4HISISAVERYLARGE
EXTENTOFFREQUENCIES

347. SOITSHOULDBEEXPECTEDTHATRADARTECHNOLOGY

348. CAPABILITIES

349. AND
APPLICATIONSWILLVARYCONSIDERABLYDEPENDINGONTHEFREQUENCYRANGEATWHICHA
RADAROPERATES2ADARSATAPARTICULARFREQUENCYBANDUSUALLYHAVEDIFFERENTCAPABILI
TIESANDCHARACTERISTICSTHANRADARSINOTHERFREQUENCYBANDS'ENERALLY

350. LONGRANGE
ISEASIERTOACHIEVEATTHELOWERFREQUENCIESBECAUSEITISEASIERTOOBTAINHIGH
POWER
TRANSMITTERS AND PHYSICALLY LARGE ANTENNAS AT THE LOWER FREQUENCIES /N THE OTHER
HAND

351. ATTHEHIGHERRADARFREQUENCIES

352. ITISEASIERTOACHIEVEACCURATEMEASUREMENTSOF
RANGEANDLOCATIONBECAUSETHEHIGHERFREQUENCIESPROVIDEWIDERBANDWIDTHWHICH
DETERMINESRANGEACCURACYANDRANGERESOLUTION ASWELLASNARROWERBEAMANTENNAS
FORAGIVENPHYSICALSIZEANTENNAWHICHDETERMINESANGLEACCURACYANDANGLERESOLU
TION )NTHEFOLLOWING

353. THEAPPLICATIONSUSUALLYFOUNDINTHEVARIOUSRADARBANDSARE
BRIEFLYINDICATED4HEDIFFERENCESBETWEENADJACENTBANDS

354. HOWEVER

355. ARESELDOMSHARP
INPRACTICE

356. ANDOVERLAPINCHARACTERISTICSBETWEENADJACENTBANDSISLIKELY
4HEWAVELENGTHSOF+ABANDRANGEFROMMMTOMM

357. WHICHQUALIFIESTHEMUNDERTHEhLEGALvDEFINITIONOF
MILLIMETERS

358. BUTJUSTBARELY

359. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°£x
(TO-(Z 4HEMAJORUSEOFTHE(BANDFORRADAR#HAPTER ISTO
DETECTTARGETSATLONGRANGESNOMINALLYOUTTONMI BYTAKINGADVANTAGEOFTHE
REFRACTIONOF(ENERGYBYTHEIONOSPHERETHATLIESHIGHABOVETHESURFACEOFTHEEARTH
2ADIOAMATEURSREFERTOTHISASSHORT
WAVEPROPAGATIONANDUSEITTOCOMMUNICATEOVER
LONGDISTANCES4HETARGETSFORSUCH(RADARSMIGHTBEAIRCRAFT

360. SHIPS

361. ANDBALLISTIC
MISSILES

362. ASWELLASTHEECHOFROMTHESEASURFACEITSELFTHATPROVIDESINFORMATIONABOUT
THEDIRECTIONANDSPEEDOFTHEWINDSTHATDRIVETHESEA
6(TO-(Z !TTHEBEGINNINGOFRADARDEVELOPMENTINTHES

363. RADARSWEREINTHISFREQUENCYBANDBECAUSETHESEFREQUENCIESREPRESENTEDTHEFRONTIER
OFRADIOTECHNOLOGYATTHATTIME)TISAGOODFREQUENCYFORLONGRANGEAIRSURVEILLANCE
ORDETECTIONOFBALLISTICMISSILES!TTHESEFREQUENCIES

364. THEREFLECTIONCOEFFICIENTON
SCATTERINGFROMTHEEARTHSSURFACECANBEVERYLARGE

365. ESPECIALLYOVERWATER

366. SOTHE
CONSTRUCTIVEINTERFERENCEBETWEENTHEDIRECTSIGNALANDTHESURFACE
REFLECTEDSIGNALCAN
INCREASESIGNIFICANTLYTHERANGEOFA6(RADAR3OMETIMESTHISEFFECTCANALMOSTDOU
BLETHERADARSRANGE(OWEVER

367. WHENTHEREISCONSTRUCTIVEINTERFERENCETHATINCREASES
THERANGE

368. THERECANBEDESTRUCTIVEINTERFERENCETHATDECREASESTHERANGEDUETOTHEDEEP
NULLSINTHEANTENNAPATTERNINTHEELEVATIONPLANE,IKEWISE

369. THEDESTRUCTIVEINTERFER
ENCECANRESULTINPOORLOW
ALTITUDECOVERAGE$ETECTIONOFMOVINGTARGETSINCLUTTER
ISOFTENBETTERATTHELOWERFREQUENCIESWHENTHERADARTAKESADVANTAGEOFTHEDOPPLER
FREQUENCYSHIFTBECAUSEDOPPLERAMBIGUITIESTHATCAUSEBLINDSPEEDS AREFARFEWER
ATLOWFREQUENCIES6(RADARSARENOTBOTHEREDBYECHOESFROMRAIN

370. BUTTHEYCANBE
AFFECTEDBYMULTIPLE
TIME
AROUNDECHOESFROMMETEORIONIZATIONANDAURORA4HERADAR
CROSSSECTIONOFAIRCRAFTAT6(ISGENERALLYLARGERTHANTHERADARCROSSSECTIONATHIGHER
FREQUENCIES6(RADARSFREQUENTLYCOSTLESSCOMPAREDTORADARSWITHTHESAMERANGE
PERFORMANCETHATOPERATEATHIGHERFREQUENCIES
!LTHOUGHTHEREAREMANYATTRACTIVEADVANTAGESOF6(RADARSFORLONG
RANGESUR
VEILLANCE

371. THEYALSOHAVESOMESERIOUSLIMITATIONS$EEPNULLSINELEVATIONANDPOOR
LOW
ALTITUDECOVERAGEHAVEBEENMENTIONED4HEAVAILABLESPECTRALWIDTHSASSIGNEDTO
RADARAT6(ARESMALLSORANGERESOLUTIONISOFTENPOOR4HEANTENNABEAMWIDTHSARE
USUALLYWIDERTHANATMICROWAVEFREQUENCIES

372. SOTHEREISPOORRESOLUTIONANDACCURACY
INANGLE4HE6(BANDISCROWDEDWITHIMPORTANTCIVILIANSERVICESSUCHAS46AND-
BROADCAST

373. FURTHERREDUCINGTHEAVAILABILITYOFSPECTRUMSPACEFORRADAR%XTERNALNOISE
LEVELSTHATCANENTERTHERADARVIATHEANTENNAAREHIGHERAT6(THANATMICROWAVE
FREQUENCIES0ERHAPSTHECHIEFLIMITATIONOFOPERATINGRADARSAT6(ISTHEDIFFICULTYOF
OBTAININGSUITABLESPECTRUMSPACEATTHESECROWDEDFREQUENCIES
)NSPITEOFITSLIMITATIONS

374. THE6(AIRSURVEILLANCERADARWASWIDELYUSEDBYTHE
3OVIET5NIONBECAUSEITWASALARGECOUNTRY

375. ANDTHELOWERCOSTOF6(RADARSMADE
THEMATTRACTIVEFORPROVIDINGAIRSURVEILLANCEOVERTHELARGEEXPANSEOFTHATCOUNTRY
4HEY HAVE SAID THEY PRODUCED A LARGE NUMBER OF6( AIR
SURVEILLANCE RADARSˆ
SOMEWEREOFVERYLARGESIZEANDLONGRANGE

376. ANDMOSTWEREREADILYTRANSPORTABLE
)TISINTERESTINGTONOTETHAT6(AIRBORNEINTERCEPTRADARSWEREWIDELYUSEDBYTHE
'ERMANSIN7ORLD7AR))OREXAMPLE

377. THE,ICHTENSTEIN3.
AIRBORNERADAROPER
ATEDFROMABOUTTOOVER-(ZINVARIOUSMODELS2ADARSATSUCHFREQUENCIES
WERENOTAFFECTEDBYTHECOUNTERMEASURECALLEDCHAFFALSOKNOWNASWINDOW
5(TO-(Z -ANYOFTHECHARACTERISTICSOFRADAROPERATINGINTHE
6(REGIONALSOAPPLYTOSOMEEXTENTAT5(5(ISAGOODFREQUENCYFOR!IRBORNE
-OVING4ARGET)NDICATION!-4) RADARINAN!IRBORNE%ARLY7ARNING2ADAR!%7

378. ASDISCUSSEDIN#HAPTER)TISALSOAGOODFREQUENCYFORTHEOPERATIONOFLONG
RANGE

379. £°£È 2!$!2(!.$//+
RADARSFORTHEDETECTIONANDTRACKINGOFSATELLITESANDBALLISTICMISSILES!TTHEUPPER
PORTIONOFTHISBANDTHERECANBEFOUNDLONG
RANGESHIPBOARDAIR
SURVEILLANCERADARS
ANDRADARSCALLEDWINDPROFILERS THATMEASURETHESPEEDANDDIRECTIONOFTHEWIND
'ROUND0ENETRATING2ADAR'02

380. DISCUSSEDIN#HAPTER

381. ISANEXAMPLEOFWHAT
ISCALLEDANULTRAWIDEBAND57 RADAR)TSWIDESIGNALBANDWIDTHSOMETIMESCOV
ERSBOTHTHE6(AND5(BANDS3UCHARADARSSIGNALBANDWIDTHMIGHTEXTEND

382. FORINSTANCE

383. FROMTO-(Z!WIDEBANDWIDTHISNEEDEDINORDERTOOBTAIN
GOODRANGERESOLUTION4HELOWERFREQUENCIESARENEEDEDTOALLOWTHEPROPAGATIONOF
RADARENERGYINTOTHEGROUND%VENSO

384. THELOSSINPROPAGATINGTHROUGHTYPICALSOIL
ISSOHIGHTHATTHERANGESOFASIMPLEMOBILE'02MIGHTBEONLYAFEWMETERS 3UCH
RANGESARESUITABLEFORLOCATINGBURIEDPOWERLINESANDPIPELINES

385. ASWELLASBURIED
OBJECTS)FARADARISTOSEETARGETSLOCATEDONTHESURFACEBUTWITHINFOLIAGE

386. SIMILAR
FREQUENCIESARENEEDEDASFORTHE'02
,BANDTO'(Z 4HISISTHEPREFERREDFREQUENCYBANDFORTHEOPERATION
OFLONG
RANGEOUTTONMI AIR
SURVEILLANCERADARS4HE!IR2OUTE3URVEILLANCE
2ADAR!232 USEDFORLONGRANGEAIR
TRAFFICCONTROLISAGOODEXAMPLE!SONEGOES
UPINFREQUENCY

387. THEEFFECTOFRAINONPERFORMANCEBEGINSTOBECOMESIGNIFICANT

388. SOTHE
RADARDESIGNERMIGHTHAVETOWORRYABOUTREDUCINGTHEEFFECTOFRAINAT,
BANDAND
HIGHERFREQUENCIES4HISFREQUENCYBANDHASALSOBEENATTRACTIVEFORTHELONG
RANGE
DETECTIONOFSATELLITESANDDEFENSEAGAINSTINTERCONTINENTALBALLISTICMISSILES
3BANDTO'(Z 4HE!IRPORT3URVEILLANCE2ADAR!32 THATMONITORS
AIRTRAFFICWITHINTHEREGIONOFANAIRPORTISAT3BAND)TSRANGEISTYPICALLYTO
NMI)FA$RADARISWANTEDONETHATDETERMINESRANGE

389. AZIMUTHANGLE

390. ANDELEVATION
ANGLE

391. ITCANBEACHIEVEDAT3BAND
)TWASSAIDPREVIOUSLYTHATLONG
RANGESURVEILLANCEISBETTERPERFORMEDATLOWFRE
QUENCIESANDTHEACCURATEMEASUREMENTOFTARGETLOCATIONISBETTERPERFORMEDATHIGH
FREQUENCIES)FONLYASINGLERADAROPERATINGWITHINASINGLEFREQUENCYBANDCANBEUSED

392. THEN3BANDISAGOODCOMPROMISE)TISALSOSOMETIMESACCEPTABLETOUSE#BANDASTHE
CHOICEFORARADARTHATPERFORMSBOTHFUNCTIONS4HE!7!#3AIRBORNEAIR
SURVEILLANCE
RADARALSOOPERATESAT3BAND5SUALLY

393. MOSTRADARAPPLICATIONSAREBESTOPERATEDINA
PARTICULARFREQUENCYBANDATWHICHTHERADARSPERFORMANCEISOPTIMUM(OWEVER

394. IN
THEEXAMPLEOFAIRBORNEAIR
SURVEILLANCERADARS

395. !7!#3ISFOUNDAT3BANDANDTHE53
.AVYS%!%7RADARAT5()NSPITEOFSUCHADIFFERENCEINFREQUENCY

396. ITHASBEENSAID
THATBOTHRADARSHAVECOMPARABLEPERFORMANCE
4HISISANEXCEPTIONTOTHEOBSERVATION
ABOUTTHEREBEINGANOPTIMUMFREQUENCYBANDFOREACHAPPLICATION
4HE.EXRADWEATHERRADAROPERATESAT3BAND)TISAGOODFREQUENCYFORTHEOBSER
VATIONOFWEATHERBECAUSEALOWERFREQUENCYWOULDPRODUCEAMUCHWEAKERRADAR
ECHOSIGNALFROMRAINSINCETHERADARECHOFROMRAINVARIESASTHEFOURTHPOWEROF
THEFREQUENCY

397. ANDAHIGHERFREQUENCYWOULDPRODUCEATTENUATIONOFTHESIGNALASIT
PROPAGATESTHROUGHTHERAINANDWOULDNOTALLOWANACCURATEMEASUREMENTOFRAINFALL
RATE4HEREAREWEATHERRADARSATHIGHERFREQUENCIES

398. BUTTHESEAREUSUALLYOFSHORTER
RANGETHAN.EXRADANDMIGHTBEUSEDFORAMORESPECIFICWEATHERRADARAPPLICATION
THANTHEACCURATEMETEOROLOGICALMEASUREMENTSPROVIDEDBY.EXRAD
#BANDTO'(Z 4HISBANDLIESBETWEEN3AND8BANDSANDHASPROPERTIES
INBETWEENTHETWO/FTEN

399. EITHER3OR8BANDMIGHTBEPREFERREDTOTHEUSEOF#BAND

400. ALTHOUGHTHEREHAVEBEENIMPORTANTAPPLICATIONSINTHEPASTFOR#BAND

401. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°£Ç
8BANDTO'(Z 4HISISARELATIVELYPOPULARRADARBANDFORMILITARY
APPLICATIONS)TISWIDELYUSEDINMILITARYAIRBORNERADARSFORPERFORMINGTHEROLESOF
INTERCEPTOR

402. FIGHTER

403. ANDATTACKOFGROUNDTARGETS

404. ASDISCUSSEDIN#HAPTER)TISALSO
POPULARFORIMAGINGRADARSBASEDON3!2AND)3!28BANDISASUITABLEFREQUENCY
FORCIVILMARINERADARS

405. AIRBORNEWEATHERAVOIDANCERADAR

406. AIRBORNEDOPPLERNAVIGATION
RADARS

407. ANDTHEPOLICESPEEDMETER-ISSILEGUIDANCESYSTEMSARESOMETIMESAT8BAND
2ADARSAT8BANDAREGENERALLYOFACONVENIENTSIZEANDARE

408. THEREFORE

409. OFINTERESTFOR
APPLICATIONSWHEREMOBILITYANDLIGHTWEIGHTAREIMPORTANTANDVERYLONGRANGEISNOT
AMAJORREQUIREMENT4HERELATIVELYWIDERANGEOFFREQUENCIESAVAILABLEAT8BANDAND
THEABILITYTOOBTAINNARROWBEAMWIDTHSWITHRELATIVELYSMALLANTENNASINTHISBAND
AREIMPORTANTCONSIDERATIONSFORHIGH
RESOLUTIONAPPLICATIONSECAUSEOFTHEHIGHFRE
QUENCYOF8BAND

410. RAINCANSOMETIMESBEASERIOUSFACTORINREDUCINGTHEPERFORMANCE
OF8
BANDSYSTEMS
+U

411. +

412. AND+AANDSTO'(Z !SONEGOESTOHIGHERRADARFREQUENCY

413. THEPHYSICALSIZEOFANTENNASDECREASE

414. ANDINGENERAL

415. ITISMOREDIFFICULTTOGENERATE
LARGETRANSMITTERPOWER4HUS

416. THERANGEPERFORMANCEOFRADARSATFREQUENCIESABOVE
8BANDISGENERALLYLESSTHANTHATOF8BAND-ILITARYAIRBORNERADARSAREFOUNDAT+U
BANDASWELLASAT8BAND4HESEFREQUENCYBANDSAREATTRACTIVEWHENARADAROFSMALLER
SIZEHASTOBEUSEDFORANAPPLICATIONNOTREQUIRINGLONGRANGE4HE!IRPORT3URFACE
$ETECTION%QUIPMENT!3$% GENERALLYFOUNDONTOPOFTHECONTROLTOWERATMAJOR
AIRPORTSHASBEENAT+UBAND

417. PRIMARILYBECAUSEOFITSBETTERRESOLUTIONTHAN8BAND)N
THEORIGINAL+BAND

418. THEREISAWATER
VAPORABSORPTIONLINEAT'(Z

419. WHICHCAUSES
ATTENUATIONTHATCANBEASERIOUSPROBLEMINSOMEAPPLICATIONS4HISWASDISCOVERED
AFTERTHEDEVELOPMENTOF+
BANDRADARSBEGANDURING7ORLD7AR))

420. WHICHISWHYBOTH
+UAND+ABANDSWERELATERINTRODUCED4HERADARECHOFROMRAINCANLIMITTHECAPABIL
ITYOFRADARSATTHESEFREQUENCIES
-ILLIMETER7AVE2ADAR !LTHOUGHTHISFREQUENCYREGIONISOFLARGEEXTENT

421. MOSTOFTHEINTERESTINMILLIMETERWAVERADARHASBEENINTHEVICINITYOF'(Z
WHERE THERE IS A MINIMUM CALLED A WINDOW IN THE ATMOSPHERIC ATTENUATION
!WINDOWISAREGIONOFLOWATTENUATIONRELATIVETOADJACENTFREQUENCIES4HEWIN
DOWAT'(ZISABOUTASWIDEASTHEENTIREMICROWAVESPECTRUM !SMENTIONED
PREVIOUSLY

422. FORRADARPURPOSES

423. THEMILLIMETERWAVEREGION

424. INPRACTICE

425. GENERALLY
STARTSAT'(ZOREVENATHIGHERFREQUENCIES4HETECHNOLOGYOFMILLIMETERWAVE
RADARSANDTHEPROPAGATIONEFFECTSOFTHEENVIRONMENTARENOTONLYDIFFERENTFROM
MICROWAVERADARS

426. BUTTHEYAREUSUALLYMUCHMORERESTRICTING5NLIKEWHATISEXPERI
ENCEDATMICROWAVES

427. THEMILLIMETERRADARSIGNALCANBEHIGHLYATTENUATEDEVENWHEN
PROPAGATINGINTHECLEARATMOSPHERE!TTENUATIONVARIESOVERTHEMILLIMETERWAVE
REGION4HEATTENUATIONINTHE'(ZWINDOWISACTUALLYHIGHERTHANTHEATTENU
ATIONOFTHEATMOSPHERICWATER
VAPORABSORPTIONLINEAT'(Z4HEONE
WAY
ATTENUATIONINTHEOXYGENABSORPTIONLINEAT'(ZISABOUTDPERKM

428. WHICH
ESSENTIALLYPRECLUDESITSAPPLICATION!TTENUATIONINRAINCANALSOBEALIMITATIONIN
THEMILLIMETERWAVEREGION
)NTERESTINMILLIMETERRADARHASBEENMAINLYBECAUSEOFITSCHALLENGESASAFRONTIER
TOBEEXPLOREDANDPUTTOPRODUCTIVEUSE)TSGOODFEATURESARETHATITISAGREATPLACEFOR
EMPLOYINGWIDEBANDWIDTHSIGNALSTHEREISPLENTYOFSPECTRUMSPACE RADARSCANHAVE
HIGHRANGE
RESOLUTIONANDNARROWBEAMWIDTHSWITHSMALLANTENNASHOSTILEELECTRONIC
COUNTERMEASURESTOMILITARYRADARSAREDIFFICULTTOEMPLOYANDITISEASIERTOHAVE

429. £°£n 2!$!2(!.$//+
AMILITARYRADARWITHLOWPROBABILITYOFINTERCEPTATTHESEFREQUENCIESTHANATLOWER
FREQUENCIES)NTHEPAST

430. MILLIMETERWAVETRANSMITTERSWERENOTCAPABLEOFANAVERAGE
POWERMORETHANAFEWHUNDREDWATTSˆANDWEREUSUALLYMUCHLESS!DVANCESIN
GYROTRONS#HAPTER CANPRODUCEAVERAGEPOWERMANYORDERSOFMAGNITUDEGREATER
THANMORECONVENTIONALMILLIMETER
WAVEPOWERSOURCES4HUS

431. AVAILABILITYOFHIGH
POWERISNOTALIMITATIONASITONCEWAS
,ASER2ADAR ,ASERSCANPRODUCEUSABLEPOWERATOPTICALFREQUENCIESANDINTHE
INFRAREDREGIONOFTHESPECTRUM4HEYCANUTILIZEWIDEBANDWIDTHVERYSHORTPULSES
ANDCANHAVEVERYNARROWBEAMWIDTHS!NTENNAAPERTURES

432. HOWEVER

433. AREMUCHSMALLER
THANATMICROWAVES!TTENUATIONINTHEATMOSPHEREANDRAINISVERYHIGH

434. ANDPER
FORMANCEINBADWEATHERISQUITELIMITED2ECEIVERNOISEISDETERMINEDBYQUANTUM
EFFECTSRATHERTHANTHERMALNOISEORSEVERALREASONS

435. LASERRADARHASHADONLYLIMITED
APPLICATION
£°ÇÊ ,

436. ,Ê
/1,
-ILITARYELECTRONICEQUIPMENT

437. INCLUDINGRADAR

438. ISIDENTIFIEDBYTHE*OINT%LECTRONICS
4YPE$ESIGNATION3YSTEM*%4$3

439. ASDESCRIBEDIN53-ILITARY3TANDARD-),
34$
$4HELETTERPORTIONOFTHEDESIGNATIONCONSISTSOFTHELETTERS!.

440. ASLANTBAR

441. ANDTHREEADDITIONALLETTERSAPPROPRIATELYSELECTEDTOINDICATEWHERETHEEQUIPMENTIS
INSTALLED

442. THETYPEOFEQUIPMENT

443. ANDITSPURPOSEOLLOWINGTHETHREELETTERSAREADASH
ANDANUMERAL4HENUMERALISASSIGNEDINSEQUENCEFORTHATPARTICULARCOMBINATIONOF
LETTERS4ABLESHOWSTHELETTERSTHATHAVEBEENUSEDFORRADARDESIGNATIONS
!SUFFIXLETTER!

444. #

445. x FOLLOWSTHEORIGINALDESIGNATIONFOREACHMODIFICATION
OFTHEEQUIPMENTWHEREINTERCHANGEABILITYHASBEENMAINTAINED4HELETTER6INPAREN
THESESADDEDTOTHEDESIGNATIONINDICATESVARIABLESYSTEMSTHOSEWHOSEFUNCTIONS
MAYBEVARIEDTHROUGHTHEADDITIONORDELETIONOFSETS

446. GROUPS

447. UNITS

448. ORCOMBINATIONS
THEREOF 7HENTHEDESIGNATIONISFOLLOWEDBYADASH

449. THELETTER4

450. ANDANUMBER

451. THE
EQUIPMENTISDESIGNEDFORTRAINING)NADDITIONTOTHE5NITED3TATES

452. THESEDESIGNA
TIONSCANALSOBEUSEDBY#ANADA

453. !USTRALIA

454. .EW:EALAND

455. ANDTHE5NITED+INGDOM
3PECIALBLOCKSOFNUMBERSARERESERVEDFORTHESECOUNTRIESURTHERINFORMATIONCAN
BEFOUNDONTHE)NTERNETUNDER-),
34$
$
4HE53EDERAL!VIATION!GENCY!! USESTHEFOLLOWINGTODESIGNATETHEIRAIR
TRAFFICCONTROLRADARS
L
!32 !IRPORT3URVEILLANCE2ADAR
L
!232 !IR2OUTE3URVEILLANCE2ADAR
L
!3$% !IRPORT3URFACE$ETECTION%QUIPMENT
L
4$72 4ERMINAL$OPPLER7EATHER2ADAR
4HENUMERALFOLLOWINGTHELETTERDESIGNATIONINDICATESTHEPARTICULARRADARMODEL
INSEQUENCE
7EATHERRADARSDEVELOPEDBYTHE537EATHER3ERVICE./!! EMPLOYTHEDES
IGNATION7324HENUMBERFOLLOWINGTHEDESIGNATIONISTHEYEARTHERADARWENTINTO
SERVICE4HUS732
$ISTHE.EXRADDOPPLERRADARTHATFIRSTENTEREDSERVICEIN
4HELETTER$INDICATESITISADOPPLERWEATHERRADAR

456. !.).42/$5#4)/.!.$/6%26)%7/2!$!2 £°£™
£°nÊ -
Ê*-/Ê

457. 6
-Ê Ê,

458. ,
!BRIEFLISTINGOFSOMEOFTHEMAJORADVANCESINTECHNOLOGYANDCAPABILITYOFRADAR
INTHETWENTIETHCENTURYISGIVEN

459. INSOMEWHATCHRONOLOGICALBUTNOTEXACTORDER

460. ASFOLLOWS
L
4HEDEVELOPMENTOF6(RADARFORDEPLOYMENTONSURFACE

461. SHIP

462. ANDAIRCRAFTFOR
MILITARYAIRDEFENSEPRIORTOANDDURING7ORLD7AR))
L
4HEINVENTIONOFTHEMICROWAVEMAGNETRONANDTHEAPPLICATIONOFWAVEGUIDETECH
NOLOGYEARLYIN77))TOOBTAINRADARSTHATCOULDOPERATEATMICROWAVEFREQUENCIES
SOTHATSMALLERANDMOREMOBILERADARSCOULDBEEMPLOYED
L
4HE MORE THAN DIFFERENT RADAR MODELS DEVELOPED AT THE -)4 2ADIATION
,ABORATORYINITSFIVEYEARSOFEXISTENCEDURING77))THATPROVIDEDTHEFOUNDATION
FORMICROWAVERADAR
L
-ARCUMSTHEORYOFRADARDETECTION
L
4HEINVENTIONANDDEVELOPMENTOFTHEKLYSTRONAND474AMPLIFIERTUBESTHATPRO
VIDEDHIGHPOWERWITHGOODSTABILITY
)NSTALLATIONFIRSTLETTER
4YPEOF%QUIPMENT
SECONDLETTER 0URPOSETHIRDLETTER
!0ILOTEDAIRCRAFT ,#OUNTERMEASURES OMBING
5NDERWATERMOBILE

463. SUBMARINE
02ADAR $$IRECTIONFINDER

464. RECONNAISSANCE
ANDSURVEILLANCE
$0ILOTLESSCARRIER 33PECIALOR
COMBINATION
'IRECONTROL
IXEDGROUND 7!RMAMENT
PECULIARTOARMAMENT
NOTOTHERWISECOVERED
..AVIGATION
''ENERALGROUNDUSE 13PECIALORCOMBINATION
+!MPHIBIOUS 22ECEIVING
--OBILEGROUND 3$ETECTINGRANGEAND
BEARING

465. SEARCH
00ORTABLE 44RANSMITTING
37ATERSHIP 7!UTOMATICFLIGHTORREMOTE
CONTROL
44RANSPORTABLEGROUND 8)DENTIFICATIONANDRECOGNITION
5'ENERALUTILITY 93URVEILLANCEANDCONTROL
BOTHFIRECONTROLANDAIRCONTROL
66EHICULARGROUND
77ATERSURFACEAND
UNDERWATERCOMBINED
:0ILOTED
PILOTLESSAIRBORNE
VEHICLESCOMBINED
4!,% *%4$3,ETTER$ESIGNATIONSTHAT0ERTAINTO2ADAR

466. £°Óä 2!$!2(!.$//+
L
4HEUSEOFTHEDOPPLERFREQUENCYSHIFTTODETECTMOVINGTARGETSINTHEPRESENCEOF
MUCHLARGERECHOESFROMCLUTTER
L
4HEDEVELOPMENTOFRADARSSUITABLEFORAIR
TRAFFICCONTROL
L
0ULSECOMPRESSION
L
-ONOPULSETRACKINGRADARWITHGOODTRACKINGACCURACYANDBETTERRESISTANCETOELEC
TRONICCOUNTERMEASURESTHANPRIORTRACKINGRADARS
L
3YNTHETICAPERTURERADAR