M
molnibalage
Guest
https://www.rt.com/usa/502996-pentagon-5g-experimentation-lethality/
Az 5G és fegyveres erők összefonódása.
(Zord)
Az 5G és fegyveres erők összefonódása.
(Zord)
Elektronikai harc - kommunikációs eszközök és EW hadviselés (Szárazföldi eszközök)
- Téma indítója gacsat
- Indítva
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- Címkék
- ecm kommunikációs eszközök
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Ha nem vagy kibékülve az alapértelmezettnek beállított sötét sablonnal, akkor a korábbi ígéretnek megfelelően bármikor átválthatsz a korábbi világos színekkel dolgozó kinézetre.
Ehhez görgess a lap aljára és a baloldalon keresd a HTKA Dark feliratú gombot. Kattints rá, majd a megnyíló ablakban válaszd a HTKA Light lehetőséget. Választásod a böngésződ elmenti cookie-ba, így amikor legközelebb érkezel ezt a műveletsort nem kell megismételned. -
Az elmúlt időszak tapasztalatai alapján házirendet kapott a topic.
Ezen témában - a fórumon rendhagyó módon - az oldal üzemeltetője saját álláspontja, meggyőződése alapján nem enged bizonyos véleményeket, mivel meglátása szerint az káros a járványhelyzet enyhítését célzó törekvésekre.
Kérünk, hogy a vírus veszélyességét kétségbe vonó, oltásellenes véleményed más platformon fejtsd ki. Nálunk ennek nincs helye. Az ilyen hozzászólásokért 1 alkalommal figyelmeztetés jár, majd folytatása esetén a témáról letiltás. Arra is kérünk, hogy a fórum más témáiba ne vigyétek át, mert azért viszont már a fórum egészéről letiltás járhat hosszabb-rövidebb időre.
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Az elmúlt időszak tapasztalatai alapján frissített házirendet kapott a topic.
--- VÁLTOZÁS A MODERÁLÁSBAN ---
A források, hírek preferáltak. Azoknak, akik veszik a fáradságot és összegyűjtik ezeket a főként harcokkal, a háború jelenlegi állásával és haditechnika szempontjából érdekes híreket, (mindegy milyen oldali) forrásokkal alátámasztják és bonuszként legalább a címet egy google fordítóba berakják, azoknak ismételten köszönjük az áldozatos munkáját és további kitartást kívánunk nekik!
Ami nem a topik témájába vág vagy akár csak erősebb hangnemben is kerül megfogalmazásra, az valamilyen formában szankcionálva lesz
Minden olyan hozzászólásért ami nem hír, vagy szorosan a konfliktushoz kapcsolódó vélemény / elemzés azért instant 3 nap topic letiltás jár. Aki pedig ezzel trükközne és folytatná másik topicban annak 2 hónap fórum ban a jussa.
Na itt egy jó cikk!
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"A Hegyi-Karabah régióba küldött orosz békefenntartók kötelékében is megjelent az RB-341V „Leer-3” elektronikus hadviselési rendszer. A komplexum gyakorlatilag a kiszemelt áldozat mobiltelefonját fordítja ellene: nemcsak pontosan fel tudja térképezni a felhasználó helyét, hanem blokkolni is tudja a kommunikációt és hamis üzenetek küldésével zavart is tud kelteni.
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A Leer-3-as csak csepp a tengerben: Oroszország számos hasonló e-harcászati rendszert fejlesztett az elmúlt években, olyan berendezésük is van, amely drónok fölött tudja átvenni az irányítást és olyan is, amely rakéták vezérlőrendszerét képes megbénítani. Bár az Egyesült Államok is rendelkezik néhány defenzív e-hadviselési rendszerrel, ezen a területen az amerikai vezetők is úgy gondolják, hogy le vannak maradva, az orosz eszközöket látva gőzerővel folyik most a fejlesztés a NATO berkein belül."
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"A Leer-3-as
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"Az ukrajnai jelenlét alapján egyébként jól látható, hogy milyen demoralizáló és zavarkeltő hatása van a harctéren egy ilyen rendszernek:
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"A Hegyi-Karabah régióba küldött orosz békefenntartók kötelékében is megjelent az RB-341V „Leer-3” elektronikus hadviselési rendszer. A komplexum gyakorlatilag a kiszemelt áldozat mobiltelefonját fordítja ellene: nemcsak pontosan fel tudja térképezni a felhasználó helyét, hanem blokkolni is tudja a kommunikációt és hamis üzenetek küldésével zavart is tud kelteni.
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A Leer-3-as csak csepp a tengerben: Oroszország számos hasonló e-harcászati rendszert fejlesztett az elmúlt években, olyan berendezésük is van, amely drónok fölött tudja átvenni az irányítást és olyan is, amely rakéták vezérlőrendszerét képes megbénítani. Bár az Egyesült Államok is rendelkezik néhány defenzív e-hadviselési rendszerrel, ezen a területen az amerikai vezetők is úgy gondolják, hogy le vannak maradva, az orosz eszközöket látva gőzerővel folyik most a fejlesztés a NATO berkein belül."
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"A Leer-3-as
- 6 kilométeres hatósugarán belül be tudja mérni bármilyen mobiltelefon pontos helyét és egy digitális térképre vetíti ki azt, ezzel meg tudják határozni például egy ellenséges alakulat pontos számát, tartózkodási helyét és nyomon tudják követni mozgásukat is,
- zavarni vagy blokkolni tudja egyszerre akár 2000 telefon kommunikációját,
- üzeneteket tud küldeni a felhasználók telekommunikációs eszközeire, összezavarva ezzel az kiszemelt osztag kommunikációját és koordinációját,
- az Aerotech forrásai szerint a komplexummal lehet mobiltelefonok memóriájában is „turkálni” és így érzékeny adatokat kinyerni a rendszerből,
- lengyel hírszerzési források szerint pedig akár egy amerikai drón fölött is át tudja venni az irányítást a Leer-3-as rendszer (erre a célra egyébként az oroszoknak egy teljesen különálló e-hadviselési rendszerük is van).
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"Az ukrajnai jelenlét alapján egyébként jól látható, hogy milyen demoralizáló és zavarkeltő hatása van a harctéren egy ilyen rendszernek:
- A 2015-ös debalcevei csata során például a régióban szolgáló katonák egy olyan üzenetet kaptak - látszólag egy másik ukrán osztagtól -, hogy a parancsnokság dezertált és ők is így fognak tenni.
- Egy másik körüzenetben azt írták az oroszok - szintén ukrán katonák nevében -, hogy a régióban állomásozó felkelők teljesen megsemmisítették a nemzeti gárda csapatait, úgyhogy ideje elfutni.
- Egyszer pedig kijevi kormány nevében küldtek SMS-t az ukrán katonáknak, megköszönve azt, hogy az összes megtakarításukat a kormányak adományozták a terrorellenes küzdelemre.
- Ezen kívül a Business Insider forrásai szerint egy olyan eset is történt, hogy a szakadár tüzéreket segítették az oroszok azzal, hogy üzenetet küldtek az ukrán katonák rokonainak arról, hogy hozzátartozójuk elesett a fronton, ezután pedig az aggódó családtagok felhívták a frontvonalon harcoló katonákat. A telefonok jeleit bemérték egy Leer-3-assal és pontos koordinátákat tudtak adni a szakadár tüzérségnek az ukrán állásoknak."
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All about Krasuh electronic warfare systems and Serbia's experiences in electronic warfare in 1999
@molnibalage,Hpasp: Érdekes írás, szerintem nektek mindenképp érdemes elolvasni. https://forum.htka.hu/members/molnibalage.31/
M
molnibalage
Guest
Az angol fordítással mondjuk úgy, hogy. kb. érthetetlen propagandaszöveget látok, hogy ez aztán mindennel mindent csinál és tönkre is teszi.
K
kamm
Guest
Itt mar volt a cikkrol szo, no meg a @Green Leader is kozulunk valo: https://forum.htka.hu/threads/a-mag...fejlesztési-irányai.499/page-4434#post-794267
A szerb cikket 4 nappal később írta a szerb légvédelem egyik tisztje.
A portfolios cikk hamarabb volt ebben a topikban linkelve, mint a "A magyar haderő lehetséges fejlesztési irányai"-ban. De ott több volt a komment, így végül is jó, hogy belinkelted.
M
molnibalage
Guest
Erre?
They also managed to identify the collisions of "invisible" bombers, such as the F-117A and B-2A
Vagy a fordító hülye, vagy aki írta. Az F-117-esek 10 km alatt repültek, az B-2-esek meg úgy 14 km táján vagy felette.
Nem véletlenül írtam azt, amit...
T
Törölt tag 1586
Guest
T
Törölt tag 1945
Guest
Ez sajnos nagyon alapszintű, alig pár oldalas írás, a History of Electronic Warfare című kötetek ennél sokkal konkrétabbak és bőségesebb információ források (szintén az AOC-től), ha beszerezheted, nagyon ajánlom őket.Megjött a tananyag...
T
Törölt tag 1586
Guest
Hmm...sajnos tényleg elég alapszintű volt.
Ez megvan? Ha igen mi a véleményed - meg úgy általában EW105 ig bezárólag az egész sorozatról - érdemes megvenni?
T
Törölt tag 1945
Guest
Hmm...sajnos tényleg elég alapszintű volt.
Ez megvan? Ha igen mi a véleményed - meg úgy általában EW105 ig bezárólag az egész sorozatról - érdemes megvenni?
EW101..104-ig van meg. Ha szereted a matekot, akkor tetszeni fog. (%-ban hogy mennyire érdekes nekem)
EW101 nagyon jól leírja a radarok felderítő képességeinek, illetve zavarásának matekját. (100%)
EW102 kicsit az EW101-et ismétli, majd az infravörös érzékeléssel foglalkozik. A második fele a rádiókommunikáció zavarásának matekjáról szól, ez a téma alapvetően engem hidegen hagy. (50%)
EW103 csak a rádiókommunikációról szól, annak matekja, illetve zavarása. Ez a téma alapvetően engem teljesen hidegen hagy, nem használom ezt a könyvet egyáltalán. (0%)
EW104 az alapokkal már nem foglalkozik, viszont végigszámol pár zavarást, konkrétan számol Dvina és Silka lokátorát, illetve részletesen ír az infra érzékelőkről. (70%)
T
Törölt tag 1945
Guest
Hmm...sajnos tényleg elég alapszintű volt.
Ez megvan? Ha igen mi a véleményed - meg úgy általában EW105 ig bezárólag az egész sorozatról - érdemes megvenni?
Ha akarod (és máshol nincs fent), akkor a tartalomjegyzéket befotózhatom.
(10~15 oldal könyvenként)
T
Törölt tag 1586
Guest
T
Törölt tag 1945
Guest
EW101 (OCR-el)
1 Introduction 1
2 Basic Mathematical Concepts 7
2.1 dB Values and Equations 7
2.1.1 Conversion to and from dB Form 8
2.1.2 Absolute Values in dB Form 8
2.1.3 dB Equations 9
2.2 The Link Equation for All EW Functions 10
2.2.1 The “One-Way Link” 10
2.2.2 Propagation Losses 12
2.2.: Receiver Sensitivity 13
2.2.4 Effective Range 14
2.3 Link Issues in Practical EW Applications 15
2.3.1 Power Out in the Ether Waves 15
2.3.2 Sensitivity in p,V/m 16
2.3.3 “Links” in Radar Operation 17
2.3.4 Interfering Signals 19
2.3.5 Low-Frequency Signals Close to the Earth 20
2.4 Relations in Spherical Triangles 20
2.4.1 The Role of Spherical Trigonometry in EW 20
2.4.2 The Spherical Triangle 21
2.4.3 Trigonometric Relationships in Any Spherical Triangle 22
2.4.4 The Right Spherical Triangle 23
2.5 EW Applications of Spherical Trigonometry 25
2.5.1 Elevation-Caused Error in Azimuth-Only
DF System 25
2.5.2 Doppler Shift 26
2.5.3 Observation Angle in 3-D Engagement 28
3 Antennas 31
3.1 Antenna Parameters and Definitions 31
3.1.1 First, Some Definitions 32
3.1.2 The Antenna Beam 32
3.1.3 More About Antenna Gain 34
3.1.4 About Polarization 34’
3.2 Types of Antennas 36
3.2.1 Selecting an Antenna to Do the Job 36
3.2.2 General Characteristics of Various Types of Antennas 37
3.3 Parameter Tradeoffs in Parabolic Antennas 39
3.3.1 Gain Versus Beamwidth 39
3.3.2 Effective Antenna Area 40
3.3.3 Antenna Gain as a Function of Diameter and Frequency 41
3.3.4 Gain of Nonsymmetrical Antennas 42
3.4 Phased Array Antennas 43
3.4.1 Phased Array Antenna Operation 43
3.4.2 Antenna Element Spacing 45
3.4.3 Phased Array Antenna Beamwidth 45
3.4.4 Phased Array Antenna Gain 46
3.4.5 Beam Steering Limitation 47
Contents ix
4 Receivers 49
4.1 Crystal Video Receiver 51
4.2 IFM Receiver 52
4.3 Tuned Radio Frequency Receiver 53
4.4 Superheterodyne Receiver 54
4.5 Fixed Tuned Receiver 55
4.6 Channelized Receiver 55
4.7 Bragg Cell Receiver 56
4.8 Compressive Receiver 57
4.9 Digital Receivers 58
4.10 Receiver Systems 59
4.10.1 Crystal Video and IFM Receivers Combined 60
4.10.2 Receivers for Difficult Signals 60
4.10.3 Special Receiver Time Shared by Several Operators 62
4.11 Receiver Sensitivity 62
4.11.1 Where Sensitivity Is Defined 63
4.11.2 The Three Components of Sensitivity 64
4.12 FM Sensitivity 67
4.12.1 FM Improvement Factor 67
4.13 Digital Sensitivity 69
4.13.1 Output SNR 69
4.13.2 Bit Error Rate 70
5 EW Processing 73
5.1 Processing Tasks 73
5.1.1 RF Threat Identification 75
5.1.2 Logic Flow in Threat Identification 75
5.2 Determining Values of Parameters 78
5.2.1 Pulse Width 78
5.2.2 Frequency 78
5.2.3 Direction of Arrival 80
5.2.4 Pulse Repetition Interval 80
5.2.5 Antenna Scan 80
5.2.6 Receiving Pulses in the Presence of CW 82
5.3 Deinterleaving 82
5.3.1 Pulse on Pulse 83
5.3.2 Deinterleaving Tools 83
5.3.3 Digital Receivers 86
5.4 Operator Interface 86
5.4.1 In General (Computers Versus Humans) 86
5.4.2 Operator Interface in the Integrated Aircraft EW Suite 88
5.5 Modem Aircraft Operator Interface 92
5.5.1 Pictorial Format Displays 92
5.5.2 Head-Up Display 93
5.5.3 Vertical-Situation Display 94
5.5.4 Horizontal-Situation Display 95
5.5.5 Multiple-Purpose Displays 96
5.5.6 Challenges 96
5.6 Operator Interface in Tactical ESM Systems 96
5.6.1 Operator Functions 97
5.6.2 Real-World Triangulation 98
5.6.3 Computer-Generated Displays 99
5.6.4 Modern Map-Based Displays 100
1 Introduction 1
2 Basic Mathematical Concepts 7
2.1 dB Values and Equations 7
2.1.1 Conversion to and from dB Form 8
2.1.2 Absolute Values in dB Form 8
2.1.3 dB Equations 9
2.2 The Link Equation for All EW Functions 10
2.2.1 The “One-Way Link” 10
2.2.2 Propagation Losses 12
2.2.: Receiver Sensitivity 13
2.2.4 Effective Range 14
2.3 Link Issues in Practical EW Applications 15
2.3.1 Power Out in the Ether Waves 15
2.3.2 Sensitivity in p,V/m 16
2.3.3 “Links” in Radar Operation 17
2.3.4 Interfering Signals 19
2.3.5 Low-Frequency Signals Close to the Earth 20
2.4 Relations in Spherical Triangles 20
2.4.1 The Role of Spherical Trigonometry in EW 20
2.4.2 The Spherical Triangle 21
2.4.3 Trigonometric Relationships in Any Spherical Triangle 22
2.4.4 The Right Spherical Triangle 23
2.5 EW Applications of Spherical Trigonometry 25
2.5.1 Elevation-Caused Error in Azimuth-Only
DF System 25
2.5.2 Doppler Shift 26
2.5.3 Observation Angle in 3-D Engagement 28
3 Antennas 31
3.1 Antenna Parameters and Definitions 31
3.1.1 First, Some Definitions 32
3.1.2 The Antenna Beam 32
3.1.3 More About Antenna Gain 34
3.1.4 About Polarization 34’
3.2 Types of Antennas 36
3.2.1 Selecting an Antenna to Do the Job 36
3.2.2 General Characteristics of Various Types of Antennas 37
3.3 Parameter Tradeoffs in Parabolic Antennas 39
3.3.1 Gain Versus Beamwidth 39
3.3.2 Effective Antenna Area 40
3.3.3 Antenna Gain as a Function of Diameter and Frequency 41
3.3.4 Gain of Nonsymmetrical Antennas 42
3.4 Phased Array Antennas 43
3.4.1 Phased Array Antenna Operation 43
3.4.2 Antenna Element Spacing 45
3.4.3 Phased Array Antenna Beamwidth 45
3.4.4 Phased Array Antenna Gain 46
3.4.5 Beam Steering Limitation 47
Contents ix
4 Receivers 49
4.1 Crystal Video Receiver 51
4.2 IFM Receiver 52
4.3 Tuned Radio Frequency Receiver 53
4.4 Superheterodyne Receiver 54
4.5 Fixed Tuned Receiver 55
4.6 Channelized Receiver 55
4.7 Bragg Cell Receiver 56
4.8 Compressive Receiver 57
4.9 Digital Receivers 58
4.10 Receiver Systems 59
4.10.1 Crystal Video and IFM Receivers Combined 60
4.10.2 Receivers for Difficult Signals 60
4.10.3 Special Receiver Time Shared by Several Operators 62
4.11 Receiver Sensitivity 62
4.11.1 Where Sensitivity Is Defined 63
4.11.2 The Three Components of Sensitivity 64
4.12 FM Sensitivity 67
4.12.1 FM Improvement Factor 67
4.13 Digital Sensitivity 69
4.13.1 Output SNR 69
4.13.2 Bit Error Rate 70
5 EW Processing 73
5.1 Processing Tasks 73
5.1.1 RF Threat Identification 75
5.1.2 Logic Flow in Threat Identification 75
5.2 Determining Values of Parameters 78
5.2.1 Pulse Width 78
5.2.2 Frequency 78
5.2.3 Direction of Arrival 80
5.2.4 Pulse Repetition Interval 80
5.2.5 Antenna Scan 80
5.2.6 Receiving Pulses in the Presence of CW 82
5.3 Deinterleaving 82
5.3.1 Pulse on Pulse 83
5.3.2 Deinterleaving Tools 83
5.3.3 Digital Receivers 86
5.4 Operator Interface 86
5.4.1 In General (Computers Versus Humans) 86
5.4.2 Operator Interface in the Integrated Aircraft EW Suite 88
5.5 Modem Aircraft Operator Interface 92
5.5.1 Pictorial Format Displays 92
5.5.2 Head-Up Display 93
5.5.3 Vertical-Situation Display 94
5.5.4 Horizontal-Situation Display 95
5.5.5 Multiple-Purpose Displays 96
5.5.6 Challenges 96
5.6 Operator Interface in Tactical ESM Systems 96
5.6.1 Operator Functions 97
5.6.2 Real-World Triangulation 98
5.6.3 Computer-Generated Displays 99
5.6.4 Modern Map-Based Displays 100
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Törölt tag 1945
Guest
6 Search 103
6.1 Definitions and Parametric Constraints 103
6.1.1 Search Dimensions 104
6.1.2 Parametric Search Tradeoffs 107
6.2 Narrowband Frequency Search Strategies 108
6.2.1 Problem Definition 108
6.2.2 Sensitivity 109
6.2.3 Communications Signals Search 110
6.2.4 Radar Signal Search 110
6.2.5 Generalities About Narrowband Search 112
6.3 The Signal Environment 112
6.3.1 Signals of Interest 113
6.3.2 Altitude and Sensitivity 113
6.3.3 Information Recovered from Signals 115
6.3.4 Types of Receivers Used in Search 116
6.3.5 Search Strategies Using Wideband Receivers 117
6.3.6 Digital Receivers 120
6.4 Look-Through 120
7 LPI Signals 123
7.1 Low-Probability-of-Intercept Signals 123
7.1.1 LPI Search Strategies 125
7.2 Frequency-Hopping Signals 125
7.2.1 Frequency Versus Time Characteristic 125
7.2.2 Frequency-Hopping Transmitter 126
7.2.3 Low Probability of Intercept 127
7.2.4 How to Detect Hoppers 127
7.2.5 How to Intercept Hoppers 128
7.2.6 How to Locate Hopping Transmitters 128
7.2.7 How to Jam Hoppers 129
7.3 Chirp Signals - 129
7.3.1 Frequency Versus Time Characteristic . 130
7.3.2 Chirped Transmitter 130
7.3.3 Low Probability of Intercept 131
7.3.4 How to Detect Chirped Signals- 131
7.3.5 How to Intercept Chirped Signals • 132
7.3.6 How to Locate Chirped Transmitters 133
7.3.7 How to Jam Chirped Signals, 133
7.4 Direct-Sequence Spread-Spectrum Signals 134
7.4.1 Frequency Versus Time Characteristic 134
7.4.2 Low Probability of Intercept 135
7.4.3 Direct-Sequence Spread-Spectrum
Transmitter 135
7.4.4 DS Receiver 135
7.4.5 Despreading Nonspread Signals 136
7.4.6 How to Detect DS Signals 137
7.4.7 How to Intercept DS Signals 137
7.4.8 How to Locate DS Transmitters 137
7.4.9 How to Jam DS Signals 138
7.5 Some Real-World Considerations 138
7.5.1 Spread-Spectrum Signal Frequency Occupancy 138
7.5.2 Partial-Band Jamming 140
7.5.3 Some Reference for More Study of LPI 142
8 Emitter Location 143
8.1 The Role of Emitter Location 143
8.2 Emitter Location Geometry 145
8.3 Emitter Location Accuracy 148
8.3.1 Intercept Geometry . 148
8.3.2 Location Accuracy Budget 150
8.3.3 Emitter Location Techniques 152
8.3.4 Calibration 153
8.4 Amplitude-Based Emitter Location 153
8.4.1 Single Directional Antenna 153
8.4.2 Watson-Watt Technique 154
8.4.3 Multiple Directional Antennas 156
8.5 Interferometer Direction Finding 158
8.5.1 Basic Configuration 158
8.5.2 Interferometric Triangle 159
8.5.3 System Configuration 161
8.6 Interferometric DF Implementation 163
8.6.1 Mirror Image Ambiguity 163
8.6.2 Long Baseline Ambiguity 165
8.6.3 Calibration 166
8.7 Direction Finding Using the Doppler Principle 167
8.7.1 The Doppler Principle 167
8.7.2 Doppler-Based Direction Finding 168
8.7.3 Practical Doppler Direction-Finding Systems 169
8.7.4 Differential Doppler 170
8.7.5 Emitter Location from Two Moving Receivers 170
8.8 Time of Arrival Emitter Location 172
8.8.1 TOA System Implementation 172
8.8.2 Time Difference of Arrival 173
8.8.3 Distance Ambiguities 175
8.8.4 Time of Arrival Comparison 175
8.8.5 Pulsed Signals 175
8.8.6 Continuously Modulated Signals 176
9 Jamming 177
9.1 Classifications of Jamming 178
9.1.1 Communications Versus Radar Jamming 178
9.1.2 Cover Versus Deceptive Jamming 180
9.1.3 Self-Protection Versus Stand-Off Jamming 180
9.1.4 Decoys 181
9.2 Jamming-to-Signal Ratio 182
9.2.1 Received Signal Power 182
9.2.2 Received Jamming Power 183
9.2.3 Jamming-to-Signal Ratio 185
9.3 Burn-Through 187
9.3.1 Burn-Through Range 187
9.3.2 Required J/S 188
9.3.3 J/S Versus Jamming Situation 188
9.3.4 Burn-Through Range for Radar Jamming (Stand-Off) 189
9.3.5 Burn-Through Range for Radar Jamming (Self-Protection) 190
9.3.6 Burn-Through Range for Communications Jamming 191
9.4 Cover Jamming 191
9.4.1 J/S Versus Jammer Power 192
9.4.2 Power Management 194
9.4.3 Look-Through 195
9.5 Range Deceptive Jamming 196
9.5.1 Range Gate Pull-OffTechnique 196
9.5.2 Resolution Cell 197
9.5.3 Pul 1-OfF Rate 198
9.5.4 Counter-Countermeasures 198
9.5.5 Range Gate Pull-In 199
9.6 Inverse Gain Jamming 200
9.6.1 Inverse Gain Jamming Technique 200
9.6.2 Inverse Gain Jamming Against Con Scan 202
9.6.3 Inverse Gain Jamming of TWS 203
9.6.4 Inverse Gain Jamming of SORO Radars 205
9.7 AGC Jamming 206
9.8 Velocity Gate Pull-Off 207
9.9 Deceptive Techniques Against Monopulse Radars 209
9.9.1 Monopulse Radar Jamming 210
9.9.2 The Radar Resolution Cell 210
9.9.3 Formation Jamming 212
9.9.4 Blinking Jamming 213
9.9.5 Terrain Bounce 214
9.9.6 Skirt Jamming 214
9.9.7 Image Jamming 215
9.9.8 Cross-Polarization Jamming 217
9.9.9 Amplitude Tracking 218
9.9.10 Coherence Jamming 219
9.9.11 Cross Eye Jamming 220
10 Decoys 223
10.1 Types of Decoys 223
10.1.1 Decoy Missions 224
10.1.2 Saturation Decoys 225
10.1.3 Detection Decoys 225
10.1.4 Seduction Decoys
10.2 RCS and Reflected Power
10.3 Passive Decoys 229
10.4 Active Decoys 231
10.5 Saturation Decoys 231
10.6 Seduction Decoys 232
10.6.1 Seduction Decoy Operating Sequence 233
10.6.2 Seduction Function in Ship Protection 235
10.6.3 Dump-Mode Decoy Operation 235
10.7 Effective RCS Through an Engagement 237
10.7.1 First, a Quick Review 237
10.7.2 A Simple Scenario 237
10.7.3 Decoy RCS Through the Scenario 239
11 Simulation 243
11.1 Definitions 243
11.1.1 Simulation Approaches 243
11.1.2 Modeling 244
11.1.3 Simulation 244
11.1.4 Emulation 245
11.1.5 Simulation for Training 245
11.1.6 Simulation forT&E 246
11.1.7 Fidelity in EW Simulation 246
11.2 Computer Simulation 247
11.2.1 The Model 247
11.2.2 Ship-Protection Model Example 248
11.2.3 Ship-Protection Simulation Example 250
11.3 Engagement Scenario Model 252
11.3.1 Numerical Values in the Model 253
11.3.2 Ship Defense with Chaff 254
11.4 Operator Interface Simulation 256
11.4.1 Primarily for Training 257
11.4.2 Two Basic Approaches 257
11.4.3 Fidelity 259
11.5 Practical Considerations in Operator
Interface Simulation 261
11.5.1 Gaming Areas 261
11.5.2 Gaming Area Indexing 262
11.5.3 Hardware Anomalies 263
11.5.4 Process Latency 264
11.5.5 Yes, But Is It Good Enough? 265
11.6 Emulation 265
11.6.1 Emulation Generation 265
11.6.2 Emulation Injection Points 266
11.6.3 General Advantages and Disadvantages
of Injection Points 269
11.7 Antenna Emulation 269
11.7.1 Antenna Characteristics 269
11.7.2 Simulation of Antenna Functions 269
11.7.3 Parabolic Antenna Example 270
11.7.4 RWR Antenna Example 271
11.7.5 Other Multiple Antenna Simulators 273
11.8 Receiver Emulation 273
11.8.1 The Receiver Function 274
11.8.2 Receiver Signal Flow 275
11.8.3 The Emulator 276
11.8.4 Signal-Strength Emulation 277
11.8.5 Processor Emulation 278
11.9 Threat Emulation 278
11.9.1 Types of Threat Emulations 278
11.9.2 Pulsed Radar Signals 278
11.9.3 Pulse Signal Emulation 281
11.9.4 Communications Signals 281
11.9.5 High-Fidelity Pulsed Emulators 282
11.10 Threat Antenna-Pattern Emulation 283
11.10.1 Circular Scan 283
11.10.2 Sector Scan 284
11.10.3 Helical Scan 284
11.10.4 Raster Scan 284
11.10.5 Conical Scan
284
11.10.6 Spiral Scan 284
11.10.7 Palmer Scan 285
11.10.8 Palmer-Raster Scan 285
11.10.9 Lobe Switching 286
11.10.10 Lobe-On Receive Only 286
11.10.11 Phased Array 287
11.10.12 Electronic Elevation Scan with
Mechanical Azimuth Scan 287
11.11 Multiple-Signal Emulation 287
11.11.1 Parallel Generators 288
11.11.2 Time-Shared Generators 288
11.11.3 A Simple Pulse-Signal Scenario 289
11.11.4 Pulse Dropout 290
11.11.5 Primary and Backup Simulators 291
11.11.6 Approach Selection 291
Appendix A 293
6.1 Definitions and Parametric Constraints 103
6.1.1 Search Dimensions 104
6.1.2 Parametric Search Tradeoffs 107
6.2 Narrowband Frequency Search Strategies 108
6.2.1 Problem Definition 108
6.2.2 Sensitivity 109
6.2.3 Communications Signals Search 110
6.2.4 Radar Signal Search 110
6.2.5 Generalities About Narrowband Search 112
6.3 The Signal Environment 112
6.3.1 Signals of Interest 113
6.3.2 Altitude and Sensitivity 113
6.3.3 Information Recovered from Signals 115
6.3.4 Types of Receivers Used in Search 116
6.3.5 Search Strategies Using Wideband Receivers 117
6.3.6 Digital Receivers 120
6.4 Look-Through 120
7 LPI Signals 123
7.1 Low-Probability-of-Intercept Signals 123
7.1.1 LPI Search Strategies 125
7.2 Frequency-Hopping Signals 125
7.2.1 Frequency Versus Time Characteristic 125
7.2.2 Frequency-Hopping Transmitter 126
7.2.3 Low Probability of Intercept 127
7.2.4 How to Detect Hoppers 127
7.2.5 How to Intercept Hoppers 128
7.2.6 How to Locate Hopping Transmitters 128
7.2.7 How to Jam Hoppers 129
7.3 Chirp Signals - 129
7.3.1 Frequency Versus Time Characteristic . 130
7.3.2 Chirped Transmitter 130
7.3.3 Low Probability of Intercept 131
7.3.4 How to Detect Chirped Signals- 131
7.3.5 How to Intercept Chirped Signals • 132
7.3.6 How to Locate Chirped Transmitters 133
7.3.7 How to Jam Chirped Signals, 133
7.4 Direct-Sequence Spread-Spectrum Signals 134
7.4.1 Frequency Versus Time Characteristic 134
7.4.2 Low Probability of Intercept 135
7.4.3 Direct-Sequence Spread-Spectrum
Transmitter 135
7.4.4 DS Receiver 135
7.4.5 Despreading Nonspread Signals 136
7.4.6 How to Detect DS Signals 137
7.4.7 How to Intercept DS Signals 137
7.4.8 How to Locate DS Transmitters 137
7.4.9 How to Jam DS Signals 138
7.5 Some Real-World Considerations 138
7.5.1 Spread-Spectrum Signal Frequency Occupancy 138
7.5.2 Partial-Band Jamming 140
7.5.3 Some Reference for More Study of LPI 142
8 Emitter Location 143
8.1 The Role of Emitter Location 143
8.2 Emitter Location Geometry 145
8.3 Emitter Location Accuracy 148
8.3.1 Intercept Geometry . 148
8.3.2 Location Accuracy Budget 150
8.3.3 Emitter Location Techniques 152
8.3.4 Calibration 153
8.4 Amplitude-Based Emitter Location 153
8.4.1 Single Directional Antenna 153
8.4.2 Watson-Watt Technique 154
8.4.3 Multiple Directional Antennas 156
8.5 Interferometer Direction Finding 158
8.5.1 Basic Configuration 158
8.5.2 Interferometric Triangle 159
8.5.3 System Configuration 161
8.6 Interferometric DF Implementation 163
8.6.1 Mirror Image Ambiguity 163
8.6.2 Long Baseline Ambiguity 165
8.6.3 Calibration 166
8.7 Direction Finding Using the Doppler Principle 167
8.7.1 The Doppler Principle 167
8.7.2 Doppler-Based Direction Finding 168
8.7.3 Practical Doppler Direction-Finding Systems 169
8.7.4 Differential Doppler 170
8.7.5 Emitter Location from Two Moving Receivers 170
8.8 Time of Arrival Emitter Location 172
8.8.1 TOA System Implementation 172
8.8.2 Time Difference of Arrival 173
8.8.3 Distance Ambiguities 175
8.8.4 Time of Arrival Comparison 175
8.8.5 Pulsed Signals 175
8.8.6 Continuously Modulated Signals 176
9 Jamming 177
9.1 Classifications of Jamming 178
9.1.1 Communications Versus Radar Jamming 178
9.1.2 Cover Versus Deceptive Jamming 180
9.1.3 Self-Protection Versus Stand-Off Jamming 180
9.1.4 Decoys 181
9.2 Jamming-to-Signal Ratio 182
9.2.1 Received Signal Power 182
9.2.2 Received Jamming Power 183
9.2.3 Jamming-to-Signal Ratio 185
9.3 Burn-Through 187
9.3.1 Burn-Through Range 187
9.3.2 Required J/S 188
9.3.3 J/S Versus Jamming Situation 188
9.3.4 Burn-Through Range for Radar Jamming (Stand-Off) 189
9.3.5 Burn-Through Range for Radar Jamming (Self-Protection) 190
9.3.6 Burn-Through Range for Communications Jamming 191
9.4 Cover Jamming 191
9.4.1 J/S Versus Jammer Power 192
9.4.2 Power Management 194
9.4.3 Look-Through 195
9.5 Range Deceptive Jamming 196
9.5.1 Range Gate Pull-OffTechnique 196
9.5.2 Resolution Cell 197
9.5.3 Pul 1-OfF Rate 198
9.5.4 Counter-Countermeasures 198
9.5.5 Range Gate Pull-In 199
9.6 Inverse Gain Jamming 200
9.6.1 Inverse Gain Jamming Technique 200
9.6.2 Inverse Gain Jamming Against Con Scan 202
9.6.3 Inverse Gain Jamming of TWS 203
9.6.4 Inverse Gain Jamming of SORO Radars 205
9.7 AGC Jamming 206
9.8 Velocity Gate Pull-Off 207
9.9 Deceptive Techniques Against Monopulse Radars 209
9.9.1 Monopulse Radar Jamming 210
9.9.2 The Radar Resolution Cell 210
9.9.3 Formation Jamming 212
9.9.4 Blinking Jamming 213
9.9.5 Terrain Bounce 214
9.9.6 Skirt Jamming 214
9.9.7 Image Jamming 215
9.9.8 Cross-Polarization Jamming 217
9.9.9 Amplitude Tracking 218
9.9.10 Coherence Jamming 219
9.9.11 Cross Eye Jamming 220
10 Decoys 223
10.1 Types of Decoys 223
10.1.1 Decoy Missions 224
10.1.2 Saturation Decoys 225
10.1.3 Detection Decoys 225
10.1.4 Seduction Decoys
10.2 RCS and Reflected Power
10.3 Passive Decoys 229
10.4 Active Decoys 231
10.5 Saturation Decoys 231
10.6 Seduction Decoys 232
10.6.1 Seduction Decoy Operating Sequence 233
10.6.2 Seduction Function in Ship Protection 235
10.6.3 Dump-Mode Decoy Operation 235
10.7 Effective RCS Through an Engagement 237
10.7.1 First, a Quick Review 237
10.7.2 A Simple Scenario 237
10.7.3 Decoy RCS Through the Scenario 239
11 Simulation 243
11.1 Definitions 243
11.1.1 Simulation Approaches 243
11.1.2 Modeling 244
11.1.3 Simulation 244
11.1.4 Emulation 245
11.1.5 Simulation for Training 245
11.1.6 Simulation forT&E 246
11.1.7 Fidelity in EW Simulation 246
11.2 Computer Simulation 247
11.2.1 The Model 247
11.2.2 Ship-Protection Model Example 248
11.2.3 Ship-Protection Simulation Example 250
11.3 Engagement Scenario Model 252
11.3.1 Numerical Values in the Model 253
11.3.2 Ship Defense with Chaff 254
11.4 Operator Interface Simulation 256
11.4.1 Primarily for Training 257
11.4.2 Two Basic Approaches 257
11.4.3 Fidelity 259
11.5 Practical Considerations in Operator
Interface Simulation 261
11.5.1 Gaming Areas 261
11.5.2 Gaming Area Indexing 262
11.5.3 Hardware Anomalies 263
11.5.4 Process Latency 264
11.5.5 Yes, But Is It Good Enough? 265
11.6 Emulation 265
11.6.1 Emulation Generation 265
11.6.2 Emulation Injection Points 266
11.6.3 General Advantages and Disadvantages
of Injection Points 269
11.7 Antenna Emulation 269
11.7.1 Antenna Characteristics 269
11.7.2 Simulation of Antenna Functions 269
11.7.3 Parabolic Antenna Example 270
11.7.4 RWR Antenna Example 271
11.7.5 Other Multiple Antenna Simulators 273
11.8 Receiver Emulation 273
11.8.1 The Receiver Function 274
11.8.2 Receiver Signal Flow 275
11.8.3 The Emulator 276
11.8.4 Signal-Strength Emulation 277
11.8.5 Processor Emulation 278
11.9 Threat Emulation 278
11.9.1 Types of Threat Emulations 278
11.9.2 Pulsed Radar Signals 278
11.9.3 Pulse Signal Emulation 281
11.9.4 Communications Signals 281
11.9.5 High-Fidelity Pulsed Emulators 282
11.10 Threat Antenna-Pattern Emulation 283
11.10.1 Circular Scan 283
11.10.2 Sector Scan 284
11.10.3 Helical Scan 284
11.10.4 Raster Scan 284
11.10.5 Conical Scan
284
11.10.6 Spiral Scan 284
11.10.7 Palmer Scan 285
11.10.8 Palmer-Raster Scan 285
11.10.9 Lobe Switching 286
11.10.10 Lobe-On Receive Only 286
11.10.11 Phased Array 287
11.10.12 Electronic Elevation Scan with
Mechanical Azimuth Scan 287
11.11 Multiple-Signal Emulation 287
11.11.1 Parallel Generators 288
11.11.2 Time-Shared Generators 288
11.11.3 A Simple Pulse-Signal Scenario 289
11.11.4 Pulse Dropout 290
11.11.5 Primary and Backup Simulators 291
11.11.6 Approach Selection 291
Appendix A 293
T
Törölt tag 1945
Guest
EW102
Contents
Preface xv
1 Introduction 1
1.1 Generalities About EW 3
1.2 Information Warfare 5
1.3 How to Understand Electronic Warfare 6
2 Threats 9
2.1 Some Definitions 9
2.1.1 Threats Versus Threat Signals 9
2.1.2 Radars Versus Communication 10
2.1.3 Types of Threats 10
2.1.4 Radar-Guided Weapons 11
2.1.5 Laser-Guided Weapons 11
2.1.6 Infrared Energy: Guided Weapons 12
2.1.7 Lethal Communications 12
2.1.8 Radar Resolution Cell 13
vii
2.2 Frequency Ranges 13
2.3 Threat Guidance Approaches 15
2.3.1 Active Guidance 15
2.3.2 Semiactive Guidance 16
2.3.3 Command Guidance 16
2.3.4 Passive Guidance 17
2.4 Scan Characteristics of Threat Radars 17
2.4.1 The Radar Scan 17
2.4.2 Antenna Beamwidth 18
2.4.3 Antenna Beam Pointing 19
2.5 Modulation Characteristics of Threat Radars 22
2.5.1 Pulse Radars 22
2.5.2 Pulse Doppler Radars 25
2.5.3 Continuous Wave Radars 25
2.5.4 Threat Radar Applications 26
2.6 Communication Signal Threats 26
2.6.1 The Nature of Communication Signals 27
2.6.2 Tactical Communication 27
2.6.3 Digital Data Links 29
2.6.4 Satellite Links 30
3 Radar Characteristics 33
3.1 The Radar Function 33
3.1.1 Types of Radars 34
3.1.2 Basic Radar Block Diagrams 35
3.2 Radar Range Equation 36
3.2.1 Radar Cross Section 39
3.2.2 Radar Detection Range 40
3.3 Detection Range Versus Detectability Range 42
3.3.1 Estimating the Sensitivity of the Radar Receiver 43
3.3.2 Example of Radar Detection Range Calculation 44
3.3.3 Detectability Range 44
3.4 Radar Modulation 48
3.5 Pulse Modulation 48
3.5.1 Unintentional Modulation on Pulses 50
3.5.2 Pulse Compression 51
3.5.3 Chirped Pulses 51
3.5.4 Digital Modulation on Pulses 53
3.6 CW and Pulse Doppler Radars 54
3.6.1 Doppler Shift 55
3.6.2 CW Radar 56
3.6.3 FM Ranging 56
3.6.4 Pulse Doppler Radar 58
3.7 Moving Target Indicator Radars 58
3.7.1 Basic MTI Operation 59
3.7.2 MTI Data Rates 61
3.7.3 Airborne Moving Target Indicator (AMTI) Radar 62
3.8 Synthetic Aperture Radars 63
3.8.1 Range Resolution 63
3.8.2 Azimuth Resolution 64
3.8.3 Focused Array SAR 66
3.9 Low Probability of Intercept Radars 67
3.9.1 LPI Techniques 67
3.9.2 Levels of LPI 68
3.9.3 LPID Radars 68
3.9.4 Detection Versus Detectability 70
3.9.5 LPI Figure of Merit 71
3.9.6 Other Factors Impacting Detection Range 72
4 Infrared and Electro-Optical Considerations in
Electronic Warfare 77
4.1 The Electromagnetic Spectrum 77
Contents ix
4.1.1 Infrared Spectrum 78
4.1.2 Blackbody Radiation 79
4.1.3 IR Transmission 80
4.1.4 EW Applications in the IR Range 80
4.1.5 Electro-Optical Devices 82
4.2 IR Guided Missiles 82
4.2.1 IR Sensors 82
4.2.2 IR Missiles 83
4.3 IR Line Scanners 87
4.3.1 Mine Detection Application 87
4.4 Infrared Imagery 90
4.4.1 The FLIR 90
4.4.2 IR Imagery Tracking 93
4.4.3 Infrared Search and Track 93
4.5 Night-Vision Devices 94
4.5.1 Types of Devices 94
4.5.2 Classical Night Operations 95
4.5.3 History of Development 95
4.5.4 Spectral Response 96
4.5.5 Implementation 96
4.6 Laser Target Designation 98
4.6.1 Laser Designator Operation 98
4.6.2 Laser Warning 99
4.6.3 Countermeasures Against Laser-Homing Missiles 100
4.7 Infrared Countermeasures 101
4.7.1 Flares 101
4.7.2 IR Jammers 103
4.7.3 IR Decoys 104
4.7.4 IR Chaff 105
5 EW Against Communications Signals 107
5.1 Frequency Ranges 107
5.2 HF Propagation 108
5.2.1 The Ionosphere 109
5.2.2 Ionospheric Reflection 110
5.2.3 HF Propagation Paths 111
5.2.4 Single-Site Locators 112
5.2.5 Emitter Location from Airborne Systems 112
5.3 VHF/UHF Propagation 113
5.3.1 Propagation Models 113
5.3.2 Free Space Propagation 113
5.3.3 Two-Ray Propagation 114
5.3.4 Knife-Edge Propagation 116
5.4 Signals in the Propagation Medium 116
5.5 Background Noise 120
5.6 Digital Communication 121
5.6.1 Digital Signals 122
5.6.2 Digitization 122
5.6.3 Digitizing Imagery 124
5.6.4 Digital Signal Format 125
5.6.5 RF Modulations for Digital Signals 126
5.6.6 Signal-to-Noise Ratio 128
5.6.7 Bit-Error Rate Versus RFSNR 128
5.6.8 Bandwidth Required for Digital Signals 129
5.6.9 Impact of Signal Bandwidth on Electronic Warfare 132
5.7 Spread Spectrum Signals 133
5.7.1 Frequency-Hopping Signals 134
5.7.2 Chirp Signals 135
5.7.3 Direct Sequence Spread Spectrum Signals 136
5.8 Communications Jamming 137
5.8.1 Jamming-to-Signal Ratio 138
5.8.2 Operation Near the Earth 139
5.8.3 Other Losses 140
5.8.4 Digital Versus Analog Signals 140
Contents xi
5.9 Jamming Spread Spectrum Signals 141
5.9.1 Jamming Frequency Hop Signals 141
5.9.2 Jamming Chirp Signals 147
5.9.3 Jamming DSSS Signals 147
5.9.4 Impact of Error-Correction Coding 149
5.10 Location of Spread Spectrum Transmitters 150
5.10.1 Location of Frequency-Hopping Transmitters 150
5.10.2 Location of Chirped Transmitters 153
5.10.3 Location of Direct Sequence Transmitters 153
5.10.4 Precision Emitter Location Techniques 153
6 Accuracy of Emitter Location Systems 155
6.1 Basic Emitter Location Approaches 156
6.2 Angle Measurement Techniques 157
6.2.1 Rotating Directional Antenna 157
6.2.2 Multiple Antenna Amplitude Comparison 158
6.2.3 Watson-Watt Technique 159
6.2.4 Doppler Technique 159
6.2.5 Distance Measuring Techniques 160
6.2.6 Interferometric Direction Finding 162
6.3 Precision Emitter Location Techniques 164
6.3.1 Time Difference of Arrival Method 164
6.3.2 Precision Emitter Location by FDOA 167
6.3.3 FDOA Against Moving Transmitters 169
6.3.4 Combined FDOA and TDOA 170
6.4 Emitter Location–Reporting Location Accuracy 171
6.4.1 RMS Error 171
6.4.2 Circular Error Probable 173
6.4.3 Elliptical Error Probable 174
6.5 Emitter Location—Error Budget 174
6.5.1 Combination of Error Elements 175
6.5.2 Impact of Reflections on AOA Error 176
6.5.3 Station Location Accuracy 176
6.5.4 Error Budget Items for Angle-of-Arrival Emitter
Location Approaches 177
6.5.5 Error Related to Signal-to-Noise Ratio 178
6.5.6 Calibration Errors 179
6.5.7 Combination of AOA System Errors 179
6.6 Conversion of AOA Errors to Location Errors 179
6.6.1 Measurement Accuracy 179
6.6.2 Circular Error Probable 182
6.7 Location Errors in Precision Location Systems 183
6.7.1 TDOA System Accuracy 183
6.7.2 Location Errors in FDOA Emitter Location Systems 187
7 Communication Satellite Links 191
7.1 The Nature of Communication Satellites 191
7.2 Terms and Definitions 192
7.3 Noise Temperature 195
7.3.1 System Noise Temperature 195
7.3.2 Antenna Noise Temperature 196
7.3.3 Line Temperature 197
7.3.4 Receiver Noise Temperature 197
7.3.5 A Noise Temperature Example 199
7.4 Link Losses 200
7.4.1 Spreading Loss 200
7.4.2 Atmospheric Loss 201
7.4.3 Rain and Fog Attenuation 202
7.4.4 Faraday Rotation 204
7.5 Link Losses in Typical Links 205
7.5.1 A Synchronous Satellite 205
7.5.2 Low-Earth-Satellite Link 208
Contents xiii
7.6 Link Performance Calculations 209
7.6.1 Synchronous Satellite Links 210
7.6.2 Low-Earth-Orbit Links 212
7.7 Relating Communication Satellite and EW Forms of
Equations 214
7.8 Jamming of Satellite Links 215
7.8.1 Downlink Jamming 216
7.8.2 Uplink Jamming 217
Appendix A: Problems with Solutions 219
Part 1 Problems from the EW 101 Book 219
Part 2 Problems from the EW 102 Book 239
Appendix B: Cross-References to EW101 Columns
in the Journal of Electronic Defense 255
EW 101 255
EW 102 256
Appendix C: Selected Bibliography 259
About the Author 263
Index 265
Contents
Preface xv
1 Introduction 1
1.1 Generalities About EW 3
1.2 Information Warfare 5
1.3 How to Understand Electronic Warfare 6
2 Threats 9
2.1 Some Definitions 9
2.1.1 Threats Versus Threat Signals 9
2.1.2 Radars Versus Communication 10
2.1.3 Types of Threats 10
2.1.4 Radar-Guided Weapons 11
2.1.5 Laser-Guided Weapons 11
2.1.6 Infrared Energy: Guided Weapons 12
2.1.7 Lethal Communications 12
2.1.8 Radar Resolution Cell 13
vii
2.2 Frequency Ranges 13
2.3 Threat Guidance Approaches 15
2.3.1 Active Guidance 15
2.3.2 Semiactive Guidance 16
2.3.3 Command Guidance 16
2.3.4 Passive Guidance 17
2.4 Scan Characteristics of Threat Radars 17
2.4.1 The Radar Scan 17
2.4.2 Antenna Beamwidth 18
2.4.3 Antenna Beam Pointing 19
2.5 Modulation Characteristics of Threat Radars 22
2.5.1 Pulse Radars 22
2.5.2 Pulse Doppler Radars 25
2.5.3 Continuous Wave Radars 25
2.5.4 Threat Radar Applications 26
2.6 Communication Signal Threats 26
2.6.1 The Nature of Communication Signals 27
2.6.2 Tactical Communication 27
2.6.3 Digital Data Links 29
2.6.4 Satellite Links 30
3 Radar Characteristics 33
3.1 The Radar Function 33
3.1.1 Types of Radars 34
3.1.2 Basic Radar Block Diagrams 35
3.2 Radar Range Equation 36
3.2.1 Radar Cross Section 39
3.2.2 Radar Detection Range 40
3.3 Detection Range Versus Detectability Range 42
3.3.1 Estimating the Sensitivity of the Radar Receiver 43
3.3.2 Example of Radar Detection Range Calculation 44
3.3.3 Detectability Range 44
3.4 Radar Modulation 48
3.5 Pulse Modulation 48
3.5.1 Unintentional Modulation on Pulses 50
3.5.2 Pulse Compression 51
3.5.3 Chirped Pulses 51
3.5.4 Digital Modulation on Pulses 53
3.6 CW and Pulse Doppler Radars 54
3.6.1 Doppler Shift 55
3.6.2 CW Radar 56
3.6.3 FM Ranging 56
3.6.4 Pulse Doppler Radar 58
3.7 Moving Target Indicator Radars 58
3.7.1 Basic MTI Operation 59
3.7.2 MTI Data Rates 61
3.7.3 Airborne Moving Target Indicator (AMTI) Radar 62
3.8 Synthetic Aperture Radars 63
3.8.1 Range Resolution 63
3.8.2 Azimuth Resolution 64
3.8.3 Focused Array SAR 66
3.9 Low Probability of Intercept Radars 67
3.9.1 LPI Techniques 67
3.9.2 Levels of LPI 68
3.9.3 LPID Radars 68
3.9.4 Detection Versus Detectability 70
3.9.5 LPI Figure of Merit 71
3.9.6 Other Factors Impacting Detection Range 72
4 Infrared and Electro-Optical Considerations in
Electronic Warfare 77
4.1 The Electromagnetic Spectrum 77
Contents ix
4.1.1 Infrared Spectrum 78
4.1.2 Blackbody Radiation 79
4.1.3 IR Transmission 80
4.1.4 EW Applications in the IR Range 80
4.1.5 Electro-Optical Devices 82
4.2 IR Guided Missiles 82
4.2.1 IR Sensors 82
4.2.2 IR Missiles 83
4.3 IR Line Scanners 87
4.3.1 Mine Detection Application 87
4.4 Infrared Imagery 90
4.4.1 The FLIR 90
4.4.2 IR Imagery Tracking 93
4.4.3 Infrared Search and Track 93
4.5 Night-Vision Devices 94
4.5.1 Types of Devices 94
4.5.2 Classical Night Operations 95
4.5.3 History of Development 95
4.5.4 Spectral Response 96
4.5.5 Implementation 96
4.6 Laser Target Designation 98
4.6.1 Laser Designator Operation 98
4.6.2 Laser Warning 99
4.6.3 Countermeasures Against Laser-Homing Missiles 100
4.7 Infrared Countermeasures 101
4.7.1 Flares 101
4.7.2 IR Jammers 103
4.7.3 IR Decoys 104
4.7.4 IR Chaff 105
5 EW Against Communications Signals 107
5.1 Frequency Ranges 107
5.2 HF Propagation 108
5.2.1 The Ionosphere 109
5.2.2 Ionospheric Reflection 110
5.2.3 HF Propagation Paths 111
5.2.4 Single-Site Locators 112
5.2.5 Emitter Location from Airborne Systems 112
5.3 VHF/UHF Propagation 113
5.3.1 Propagation Models 113
5.3.2 Free Space Propagation 113
5.3.3 Two-Ray Propagation 114
5.3.4 Knife-Edge Propagation 116
5.4 Signals in the Propagation Medium 116
5.5 Background Noise 120
5.6 Digital Communication 121
5.6.1 Digital Signals 122
5.6.2 Digitization 122
5.6.3 Digitizing Imagery 124
5.6.4 Digital Signal Format 125
5.6.5 RF Modulations for Digital Signals 126
5.6.6 Signal-to-Noise Ratio 128
5.6.7 Bit-Error Rate Versus RFSNR 128
5.6.8 Bandwidth Required for Digital Signals 129
5.6.9 Impact of Signal Bandwidth on Electronic Warfare 132
5.7 Spread Spectrum Signals 133
5.7.1 Frequency-Hopping Signals 134
5.7.2 Chirp Signals 135
5.7.3 Direct Sequence Spread Spectrum Signals 136
5.8 Communications Jamming 137
5.8.1 Jamming-to-Signal Ratio 138
5.8.2 Operation Near the Earth 139
5.8.3 Other Losses 140
5.8.4 Digital Versus Analog Signals 140
Contents xi
5.9 Jamming Spread Spectrum Signals 141
5.9.1 Jamming Frequency Hop Signals 141
5.9.2 Jamming Chirp Signals 147
5.9.3 Jamming DSSS Signals 147
5.9.4 Impact of Error-Correction Coding 149
5.10 Location of Spread Spectrum Transmitters 150
5.10.1 Location of Frequency-Hopping Transmitters 150
5.10.2 Location of Chirped Transmitters 153
5.10.3 Location of Direct Sequence Transmitters 153
5.10.4 Precision Emitter Location Techniques 153
6 Accuracy of Emitter Location Systems 155
6.1 Basic Emitter Location Approaches 156
6.2 Angle Measurement Techniques 157
6.2.1 Rotating Directional Antenna 157
6.2.2 Multiple Antenna Amplitude Comparison 158
6.2.3 Watson-Watt Technique 159
6.2.4 Doppler Technique 159
6.2.5 Distance Measuring Techniques 160
6.2.6 Interferometric Direction Finding 162
6.3 Precision Emitter Location Techniques 164
6.3.1 Time Difference of Arrival Method 164
6.3.2 Precision Emitter Location by FDOA 167
6.3.3 FDOA Against Moving Transmitters 169
6.3.4 Combined FDOA and TDOA 170
6.4 Emitter Location–Reporting Location Accuracy 171
6.4.1 RMS Error 171
6.4.2 Circular Error Probable 173
6.4.3 Elliptical Error Probable 174
6.5 Emitter Location—Error Budget 174
6.5.1 Combination of Error Elements 175
6.5.2 Impact of Reflections on AOA Error 176
6.5.3 Station Location Accuracy 176
6.5.4 Error Budget Items for Angle-of-Arrival Emitter
Location Approaches 177
6.5.5 Error Related to Signal-to-Noise Ratio 178
6.5.6 Calibration Errors 179
6.5.7 Combination of AOA System Errors 179
6.6 Conversion of AOA Errors to Location Errors 179
6.6.1 Measurement Accuracy 179
6.6.2 Circular Error Probable 182
6.7 Location Errors in Precision Location Systems 183
6.7.1 TDOA System Accuracy 183
6.7.2 Location Errors in FDOA Emitter Location Systems 187
7 Communication Satellite Links 191
7.1 The Nature of Communication Satellites 191
7.2 Terms and Definitions 192
7.3 Noise Temperature 195
7.3.1 System Noise Temperature 195
7.3.2 Antenna Noise Temperature 196
7.3.3 Line Temperature 197
7.3.4 Receiver Noise Temperature 197
7.3.5 A Noise Temperature Example 199
7.4 Link Losses 200
7.4.1 Spreading Loss 200
7.4.2 Atmospheric Loss 201
7.4.3 Rain and Fog Attenuation 202
7.4.4 Faraday Rotation 204
7.5 Link Losses in Typical Links 205
7.5.1 A Synchronous Satellite 205
7.5.2 Low-Earth-Satellite Link 208
Contents xiii
7.6 Link Performance Calculations 209
7.6.1 Synchronous Satellite Links 210
7.6.2 Low-Earth-Orbit Links 212
7.7 Relating Communication Satellite and EW Forms of
Equations 214
7.8 Jamming of Satellite Links 215
7.8.1 Downlink Jamming 216
7.8.2 Uplink Jamming 217
Appendix A: Problems with Solutions 219
Part 1 Problems from the EW 101 Book 219
Part 2 Problems from the EW 102 Book 239
Appendix B: Cross-References to EW101 Columns
in the Journal of Electronic Defense 255
EW 101 255
EW 102 256
Appendix C: Selected Bibliography 259
About the Author 263
Index 265
T
Törölt tag 1945
Guest
EW103
Contents
Preface xiii
1 Introduction 1
1.1 Nature of Communications 1
1.2 Frequency Ranges 2
1.3 Roadmap to the Book 3
1.4 dB Math 4
1.4.1 dB Values 5
1.4.2 Conversion to and from dB Form 5
1.4.3 Converting to dB Using a Slide Rule 7
1.4.4 Absolute Values in dB Form 8
1.4.5 dB Equations 9
2 Communications Signals 13
2.1 Analog Modulations 13
2.2 Digital Modulations 16
2.2.1 Transmission of Analog or Digital Information 16
2.2.2 Digitization 17
2.2.3 Digital RF Modulations 19
2.2.4 Bandwidth of Digital Signals 23
2.2.5 Digital Signal Structure 26
2.3 Noise 27
2.4 LPI Signals 30
2.4.1 Pseudo-Random Codes 33
2.4.2 Frequency Hopping Signals 36
2.4.3 Chirp Signals 41
2.4.4 Direct Sequence Spread Spectrum Signals 43
2.4.5 Combined Technique LPI Signals 47
2.4.6 Cell Phone Signals 49
2.5 Error-Correction Codes 51
3 Communication Antennas 55
3.1 Antenna Parameters 55
3.1.1 Types of Antennas 56
3.1.2 General Characteristics of Various Types of Antennas 57
3.2 Important Types of Communication Antennas 59
3.3 The Antenna Beam 59
3.4 More About Antenna Gain 62
3.5 Polarization 62
3.6 Phased Arrays 63
3.6.1 Phased Array Beamwidth and Gain 65
3.7 Parabolic Dish Antennas 66
4 Communications Receivers 75
4.1 Types of Receivers 75
4.1.1 Pulse Receivers 76
4.1.2 Superheterodyne Receiver 79
4.1.3 Tuned Radio Frequency Receiver 81
4.1.4 Fixed-Tuned Receiver 82
4.1.5 Channelized Receiver 82
4.1.6 Bragg Cell Receiver 84
4.1.7 Compressive Receiver 85
4.1.8 The Digital Receiver 86
4.2 Digitization 88
4.2.1 Sampling Rates 89
4.2.2 Digital Waveforms 89
4.2.3 Digitizing Techniques 90
4.2.4 I & Q Digitization 91
4.3 Digitized Signal Quality Issues 91
4.3.1 Chip Detection 92
4.3.2 Catching a Frequency Hopping Signal 93
4.4 Receiver System Sensitivity 95
4.4.1 kTB 97
4.4.2 Noise Figure 98
4.4.3 Required Predetection Signal-to-Noise Ratio 99
4.5 Receiver System Dynamic Range 105
4.5.1 Analog Versus Digital Dynamic Range 106
4.5.2 Analog Receiver Dynamic Range 107
4.5.3 Digital Dynamic Range 110
4.6 Typical Receiver System Configurations 111
4.6.1 Multiple Receiver Reconnaissance and Electronic
Support Systems 112
4.6.2 Multiple Receiver Systems 113
4.6.3 Remote Receiving Systems 116
5 Communications Propagation 119
5.1 One-Way Link 119
5.2 The One-Way Link Equation 119
5.3 Propagation Losses 123
5.4 Line-of-Sight Propagation 124
5.5 Two-Ray Propagation 129
Contents vii
5.6 Fresnel Zone 134
5.7 Knife-Edge Diffraction 137
5.8 Atmospheric and Rain Losses 140
5.8.1 Atmospheric Loss 140
5.9 HF Propagation 143
5.10 Satellite Links 147
6 Search for Communication Emitters 153
6.1 Probability of Intercept (POI) 154
6.2 Search Strategies 154
6.2.1 General Search 154
6.2.2 Directed Search 154
6.2.3 Sequentially Qualified Search 155
6.2.4 A Useful Search Tool 155
6.2.5 Practical Considerations Affecting Search 156
6.3 System Configurations 158
6.3.1 Types of Receivers Used for Search 160
6.3.2 Digitally Tuned Receiver 161
6.3.3 Digital Receivers 163
6.3.4 Frequency Measuring Receivers 163
6.3.5 Energy Detection Receivers 164
6.4 The Signal Environment 167
6.4.1 Angular Coverage 168
6.4.2 Channel Occupancy 169
6.4.3 Sensitivity 169
6.5 Radio Horizon 170
6.6 Search for Low Probability of Intercept Signals 174
6.6.1 LPI Search Strategies 175
6.6.2 Frequency Hoppers 176
6.6.3 Chirp Signals 177
6.6.4 Direct Sequence Spread Spectrum Signal 177
6.7 Look Through 178
6.8 Fratricide 181
6.9 Search Strategy Examples 181
6.9.1 Narrowband Search 181
6.9.2 Hand-Off from Wideband Receiver 185
6.9.3 Search with a Digital Receiver 185
7 Location of Communications Emitters 187
7.1 Emitter Location Approaches 187
7.1.1 Triangulation 188
7.1.2 Single-Site Location 189
7.1.3 Azimuth and Elevation 191
7.1.4 Other Location Approaches 191
7.2 Accuracy Definitions 193
7.2.1 RMS Error 193
7.2.2 Circular Error Probable and Elliptical Error Probable 195
7.2.3 Calibration 198
7.3 Site Location and North Reference 198
7.4 Moderate Accuracy Techniques 203
7.4.1 Watson-Watt Direction Finding Technique 204
7.4.2 Doppler Direction-Finding Technique 204
7.5 High Accuracy Techniques 207
7.5.1 Single Baseline Interferometer 207
7.5.2 Multiple Baseline Precision Interferometer 211
7.5.3 Correlative Interferometer 212
7.6 Precision Emitter Location 212
7.6.1 Time Difference of Arrival Method 214
7.6.2 Precision Emitter Location by Frequency Difference
of Arrival 218
7.6.3 Combined FDOA and TDOA 221
7.7 Emitter Location—Error Budget 222
Contents ix
7.7.1 Combination of Error Elements 223
7.8 Locating Spread Spectrum Emitters 225
7.8.1 Locating Frequency Hoppers 225
7.8.2 Chirp Emitters 231
7.8.3 Direct Sequence Spread Spectrum Emitters 232
7.8.4 Precision Emitter Location Techniques Against LPI
Emitters 232
8 Intercept of Communications Signals 235
8.1 The Intercept Link 236
8.1.1 Intercept of a Directional Transmission 237
8.1.2 Intercept of a Nondirectional Transmission 238
8.1.3 Airborne Intercept System 241
8.1.4 Nonline-of-Sight Intercept 242
8.2 Intercept of Weak Signal in Strong Signal
Environment 244
8.3 Intercept of LPI Signals 245
8.3.1 Intercept of Frequency Hoppers 245
8.3.2 Intercept of Chirped Signals 246
8.3.3 Intercept of Direct Sequence Spread Spectrum Signals 247
9 Communications Jamming 251
9.1 Jammer-to-Signal Ratio 252
9.1.1 Other Losses 254
9.1.2 Stand-In Jamming 254
9.2 Digital Versus Analog Signals 255
9.2.1 Pulse Jamming 258
9.3 Jamming Spread Spectrum Signals 258
9.3.1 Partial Band Jamming 259
9.3.2 Jamming Frequency Hop Signals 262
9.3.3 Jamming Chirp Signals 267
9.3.4 Jamming Direct Sequence Spread Spectrum Signals 267
9.3.5 Jamming of Combined Mode Spread Spectrum
Signals 269
9.4 Impact of Error-Correction Coding on Jamming 270
9.4.1 Jamming Cell Phones 270
9.4.2 Jam the Uplink 271
9.4.3 Jam the Downlink 272
Appendix A Problems with Solutions 275
Appendix B Bibliography 307
Appendix C Using the Included CD 311
About the Author 317
Index 319
Contents
Preface xiii
1 Introduction 1
1.1 Nature of Communications 1
1.2 Frequency Ranges 2
1.3 Roadmap to the Book 3
1.4 dB Math 4
1.4.1 dB Values 5
1.4.2 Conversion to and from dB Form 5
1.4.3 Converting to dB Using a Slide Rule 7
1.4.4 Absolute Values in dB Form 8
1.4.5 dB Equations 9
2 Communications Signals 13
2.1 Analog Modulations 13
2.2 Digital Modulations 16
2.2.1 Transmission of Analog or Digital Information 16
2.2.2 Digitization 17
2.2.3 Digital RF Modulations 19
2.2.4 Bandwidth of Digital Signals 23
2.2.5 Digital Signal Structure 26
2.3 Noise 27
2.4 LPI Signals 30
2.4.1 Pseudo-Random Codes 33
2.4.2 Frequency Hopping Signals 36
2.4.3 Chirp Signals 41
2.4.4 Direct Sequence Spread Spectrum Signals 43
2.4.5 Combined Technique LPI Signals 47
2.4.6 Cell Phone Signals 49
2.5 Error-Correction Codes 51
3 Communication Antennas 55
3.1 Antenna Parameters 55
3.1.1 Types of Antennas 56
3.1.2 General Characteristics of Various Types of Antennas 57
3.2 Important Types of Communication Antennas 59
3.3 The Antenna Beam 59
3.4 More About Antenna Gain 62
3.5 Polarization 62
3.6 Phased Arrays 63
3.6.1 Phased Array Beamwidth and Gain 65
3.7 Parabolic Dish Antennas 66
4 Communications Receivers 75
4.1 Types of Receivers 75
4.1.1 Pulse Receivers 76
4.1.2 Superheterodyne Receiver 79
4.1.3 Tuned Radio Frequency Receiver 81
4.1.4 Fixed-Tuned Receiver 82
4.1.5 Channelized Receiver 82
4.1.6 Bragg Cell Receiver 84
4.1.7 Compressive Receiver 85
4.1.8 The Digital Receiver 86
4.2 Digitization 88
4.2.1 Sampling Rates 89
4.2.2 Digital Waveforms 89
4.2.3 Digitizing Techniques 90
4.2.4 I & Q Digitization 91
4.3 Digitized Signal Quality Issues 91
4.3.1 Chip Detection 92
4.3.2 Catching a Frequency Hopping Signal 93
4.4 Receiver System Sensitivity 95
4.4.1 kTB 97
4.4.2 Noise Figure 98
4.4.3 Required Predetection Signal-to-Noise Ratio 99
4.5 Receiver System Dynamic Range 105
4.5.1 Analog Versus Digital Dynamic Range 106
4.5.2 Analog Receiver Dynamic Range 107
4.5.3 Digital Dynamic Range 110
4.6 Typical Receiver System Configurations 111
4.6.1 Multiple Receiver Reconnaissance and Electronic
Support Systems 112
4.6.2 Multiple Receiver Systems 113
4.6.3 Remote Receiving Systems 116
5 Communications Propagation 119
5.1 One-Way Link 119
5.2 The One-Way Link Equation 119
5.3 Propagation Losses 123
5.4 Line-of-Sight Propagation 124
5.5 Two-Ray Propagation 129
Contents vii
5.6 Fresnel Zone 134
5.7 Knife-Edge Diffraction 137
5.8 Atmospheric and Rain Losses 140
5.8.1 Atmospheric Loss 140
5.9 HF Propagation 143
5.10 Satellite Links 147
6 Search for Communication Emitters 153
6.1 Probability of Intercept (POI) 154
6.2 Search Strategies 154
6.2.1 General Search 154
6.2.2 Directed Search 154
6.2.3 Sequentially Qualified Search 155
6.2.4 A Useful Search Tool 155
6.2.5 Practical Considerations Affecting Search 156
6.3 System Configurations 158
6.3.1 Types of Receivers Used for Search 160
6.3.2 Digitally Tuned Receiver 161
6.3.3 Digital Receivers 163
6.3.4 Frequency Measuring Receivers 163
6.3.5 Energy Detection Receivers 164
6.4 The Signal Environment 167
6.4.1 Angular Coverage 168
6.4.2 Channel Occupancy 169
6.4.3 Sensitivity 169
6.5 Radio Horizon 170
6.6 Search for Low Probability of Intercept Signals 174
6.6.1 LPI Search Strategies 175
6.6.2 Frequency Hoppers 176
6.6.3 Chirp Signals 177
6.6.4 Direct Sequence Spread Spectrum Signal 177
6.7 Look Through 178
6.8 Fratricide 181
6.9 Search Strategy Examples 181
6.9.1 Narrowband Search 181
6.9.2 Hand-Off from Wideband Receiver 185
6.9.3 Search with a Digital Receiver 185
7 Location of Communications Emitters 187
7.1 Emitter Location Approaches 187
7.1.1 Triangulation 188
7.1.2 Single-Site Location 189
7.1.3 Azimuth and Elevation 191
7.1.4 Other Location Approaches 191
7.2 Accuracy Definitions 193
7.2.1 RMS Error 193
7.2.2 Circular Error Probable and Elliptical Error Probable 195
7.2.3 Calibration 198
7.3 Site Location and North Reference 198
7.4 Moderate Accuracy Techniques 203
7.4.1 Watson-Watt Direction Finding Technique 204
7.4.2 Doppler Direction-Finding Technique 204
7.5 High Accuracy Techniques 207
7.5.1 Single Baseline Interferometer 207
7.5.2 Multiple Baseline Precision Interferometer 211
7.5.3 Correlative Interferometer 212
7.6 Precision Emitter Location 212
7.6.1 Time Difference of Arrival Method 214
7.6.2 Precision Emitter Location by Frequency Difference
of Arrival 218
7.6.3 Combined FDOA and TDOA 221
7.7 Emitter Location—Error Budget 222
Contents ix
7.7.1 Combination of Error Elements 223
7.8 Locating Spread Spectrum Emitters 225
7.8.1 Locating Frequency Hoppers 225
7.8.2 Chirp Emitters 231
7.8.3 Direct Sequence Spread Spectrum Emitters 232
7.8.4 Precision Emitter Location Techniques Against LPI
Emitters 232
8 Intercept of Communications Signals 235
8.1 The Intercept Link 236
8.1.1 Intercept of a Directional Transmission 237
8.1.2 Intercept of a Nondirectional Transmission 238
8.1.3 Airborne Intercept System 241
8.1.4 Nonline-of-Sight Intercept 242
8.2 Intercept of Weak Signal in Strong Signal
Environment 244
8.3 Intercept of LPI Signals 245
8.3.1 Intercept of Frequency Hoppers 245
8.3.2 Intercept of Chirped Signals 246
8.3.3 Intercept of Direct Sequence Spread Spectrum Signals 247
9 Communications Jamming 251
9.1 Jammer-to-Signal Ratio 252
9.1.1 Other Losses 254
9.1.2 Stand-In Jamming 254
9.2 Digital Versus Analog Signals 255
9.2.1 Pulse Jamming 258
9.3 Jamming Spread Spectrum Signals 258
9.3.1 Partial Band Jamming 259
9.3.2 Jamming Frequency Hop Signals 262
9.3.3 Jamming Chirp Signals 267
9.3.4 Jamming Direct Sequence Spread Spectrum Signals 267
9.3.5 Jamming of Combined Mode Spread Spectrum
Signals 269
9.4 Impact of Error-Correction Coding on Jamming 270
9.4.1 Jamming Cell Phones 270
9.4.2 Jam the Uplink 271
9.4.3 Jam the Downlink 272
Appendix A Problems with Solutions 275
Appendix B Bibliography 307
Appendix C Using the Included CD 311
About the Author 317
Index 319