Electronic Aids to Navigation: Radar and ARPA

Roger Lownsborough I. Eng., F.I.E.I.E.

Senior Lecturer in Communications Engineering Southampton Institute of Highcr Education

David Calcutt M.SC., C.Eng., M.I.E.E.

Senior Lecturer in the School of Systems Engineering University of Portsmouth

Edward h o l d A member of the Hodder Headline Group LONDON MELBOURNE AUCKLAND

Contents

Preface

Acknowledgements

PART 1 PRIMARY AND SECONDARY RADAR

1 Primary Pulse Radar 1.1 Introduction 1.2 Primary pulse radar

2 Operating Characteristics of a Basic Radar System 2.1 Transmitted pulse duration (8) 2.2 Pulse repetition frequency (prf) 2.3 Pulse repetition period (prp) 2.4 Carrier frequency 2.5 Peak power (P,) 2.6 Average power (P,,) 2.7 Duty cycle (duty ratio) 2.8 Choice of values for the factors affecting the navigation

characteristics of a marine radar

3 Basic Primary Pulse Radar System 3.1 Prf generator 3.2 Modulator 3.3 Magnetron 3.4 Wave-guide 3.5 Duplexer (TR cell) 3.6 Scanner 3.7 Bearing transmission system 3.8 Frequency changer 3.9 Pre-IF or head amplifier 3.10 Anti-sea clutter 3.11 Main IF amplifier 3.12 Second detector 3.13 Rain clutter 3.14 Video mixer and video amplifier 3.15 Gate pulse generator 3.16 Time-base generator 3.17 Range ring generator 3.18 Variable range marker 3.19 Heading line

viii Contents

4 Propagation of Radar Waves 4.1 Introduction 4.2 Super refraction 4.3 Ducting or trapping 4.4 Sub-rcfraction 4.5 Summary of anomalous propagation conditions 4.6 Effects of the earth's surface: lobing 4.7 The effect of rain, hail, sleet and snow 4.8 Spurious echoes and effects 4.9 Free-space radar range equation

5 Transmission Lines 5.1 Open wire feeder 5.2 Artificial transmission lines

6 The Modulator 6.1 Resonant choke charging

7 Magnetron 7.1 Magnetron action

8 Waveguide

9 Scanner

10 Power Monitor

11 Bearing Transmission System

12 Duplexing

13 Mixer Stage 13.1 The balanced mixer hybrid ring or rat race

14 Receiver 14.1 Noise and bandwidth considerations 14.2 Bandwidth 14.3 Logarithmic amplifier 14.4 Video 14.5 Automatic frequency control 14.6 Swept gain 14.7 Digital video

15 Cathode Ray Tube (ppi Display)

16 Shift and Deflection 16.1 Shift 16.2 Deflection

17 Display Presentation

18 True Motion 18.1 Scaling amplifier 18.2 Resolver 18.3 Integrator 18.4 In-line tidal correction 18.5 Resolved tide 18.6 Digitally controlled true motion

19 Raster Scan Display 19.1 Raster 19.2 Interlaced scanning 19.3 Raster scan crt 19.4 Colour displays 19.5 Shadow mask tube principles 19.6 Deflection systems 19.7 Video 19.8 Memory mapping

20 Inter-switched Radar Systems

21 Radar Reflectors

22 Secondarv Radar 22.1 on 22.2 Search and Rescue Radar Transponder (SART)

PART 2 AUTOMATIC AIDS

23 Introduction to ARPA

24 An ARPA system 24.1 Introduction 24.2 Tracker 24.3 StartIStop generator 24.4 Video generation 24.5 CorrelatorIGuard ring processors 24.6 Range filter 24.7 Gate sequencer operation 24.8 Common memories 24.9 Radar expansion board

25 Operating instructions for Kelvin Hughes HR ARPA 25.1 Introduction 25.2 Using the ARPA system 25.3 ARPA alarms 25.4 Trial manoeuvre 25.5 Simulation mode 25.6 Mapping facilities 25.7 Interfacing options 25.8 ARPA acquisition and tracking accuracy

Appendix 1 IMO Performance Standards for ARPA 1 Introduction 2 Detinitions 3 Performance standards Annex Definition of terms

Appendix 2 ARPA video symbols and control names and Recommended Code of Practice 227

Appendix 3 Brief Details pf the Microprocessor and Support Chips Referred to in the Text

Appendix 4 Glossary of Terms Used in Part 2 (ARPA)

Index

Index

Antennagain 59 Antcnnn radiutiurl

~~bilrilclrristtcs 47 Antcnn;~ receiving aperture hi) ARPA (Aul<,mi~tic Radar

Plotting Aids) 173 cl.tcy. accurilc) 2111.214 alarms 175, 1'17.207

L , > 7

CPA 174. lY7.202.208.215 gats srqurnccr 189 gni~rd ring plucessor 176.

177, 186 guard lings 174 puilrdrc,nrs 174. 175. 197.

2114 history 173, 175, 147, 2111 TIC) port 177. 180. I86 irllcrlacing<,ptiolls 215 maps 17.1.210,21h niivig;%ftnn lines 171 r;tdar extrunri<,n ho;lrrl I'Jl

Biili>nced mlacr 120 Bandhidth oi hrilcl ;lmplificr 41

of rcccivcr IS. 124. 126 clt IF anlplificr I2h

Ueilmhiclth calculation 48 Bcamwidth o i u n t m n ; ~ array 48 Rearing cursor lil Bearin:: determination 5 He;~ring disrriminatiun 2h

cnlculalic,n 27 Rc;~l-~ng transmission bystem 8,

13. 39, 107 rl~gitnl I111 tolaling deflection cud systcn~

8. 107 sliltionary rlcflcctio~l coil

\ystcm 8. 108 sine-coctnc i-csolvct Ill8 phase coohoi<,ub reclilirr 10'J \L.rYO motel. Ill8 synchlo traa~s~r,itter 1118

Urightrning pulse W Blind acctar\iarc\ 57

range lilier 188 (~';!pitcitivc iris 113 simulation mode 175. El0 Carrier lrcooencv If,

target swap 174. 220 talgcl ilciluisition 175. 1'17.

714 . . TCPA 174. 1117. 2111.2118. 215

typical parnmclrrc 175 *ideugrncration 184

Artificial lue inout l4h .. . Attc~luiltiun of radar wsvc in

frcs space 5 1 Aurnu;~t ton due to

lhydn~mrluors 51, 52 Aurn t~ ;~ t i on provided by TR

113 Automatic frequency omtrrll

IlO. l2L1

for 'S' haild l j ior 'X'hanrl 17

Cat tedan coordinates 15') Cil*a,dc amplifier 41 Cathode ray luhe for ppi display

1.36 construcliun 136 diapoaal of I38 operation 137 xlfn handling 138

Cathode r i ~ ) tuhc for rastcl scan 17,. ...,,

C .tvtl? rncitiltion 82. Ill4 r h o k c joint 9.1 Circulilr n<,larisation 52 ('hlttcr citccts due to s~.aoner

height 29.33 Calout display 156. I611 Currclarcd vidco 13.1 Crystals 119

chi~r;ictcri~tics 119 cutrent 120 kmt-hack ratio 118

Digital vid~.,, 20. 131 L)igit;~l scnn convslsitln (DSC)

155. 158 Uigitnl true n~ution 153 r)lrrcu~n;il an1cnn:I Y7 L)itcctioll;rl c o r ~ ~ l e r 118

Display caIihr>~tic~n [J, Ill ptcasntation 143

r)ncting of radar w;i\,cs 1 V Duplex~.r 12. 14.38. l I2 I)uty C ~ C I C ! ~ ~ I 17

culculati<,n 17 I))n;lmic g;lin control 110

Electronic Bearing Indic;!tol (FRI) Ill. 43

F;llsc iilirrm with digltnl vidco 132

~ ~

c ~ ~ n ~ t r u c t i o n 117 opcraLi,ln I l h

t langcjoint 94 F,,cus h trcc-spare mngs equation 58 Frcuurncv chilnerr 34

Gain of head amplifier 41 Gillc polse gcncratur 44 Grazing arlglc 29 Group vcloclty Y1 Gunn diode Ioc;tl oscillator 40,

121, I21 noise I25 operariun 123 turlirlg 123

Gym stabilisation 1.14. 146

Hail. elfcclh ul 51 H;ilfw:wc dipolc YO Head amplifier 40 He;xling markcr 11.43

Index 245

Heiidlng line 4.i adlustment ~ ~ f r c n n n c r contact

101 ad,justrncnt ;after magnrtron

chanpr I00 ii~inluth pulsc I10

1~oriznnr;il heamwidth 6. 25. 26.33

c:ilcnliltic,n of 98 Hdd-off diodc 7h Hull cur-oil virlue 87 Hyhrid ringmiacr 121) Ilydromcicorr, rfficts 51

In- l~nc tidc fur truc motion 151 Indilcct cchoes 5.1

rliminutiun ut 55 Inductive iris l l i Inserti,,n 1ohh ofTRccl l 114 Intcgrato! for truc mulion 149 lntcrferencr (\ihibls) 54 Intcrfsrcncc rcjcction 134 Interlaced scilnningfot rartcr

scan dlsplziy 155 lntermrdialc Frequency (IF)

40. 118 Intcrswirchud ryslerrls 162 1F;lrnpliIivr 42

handwidth 176

.Iointr in warcguidc '43. 44

Kcep-;,live boltagc 113 Klntron local osc~ll;~lc,r 40. 121

Lechcrllnc 81 I .<,h>ng rlfccts 50 Local oscillator 40

lrcqucrtcy 118 cnoisc 120

I.og input lor true ln~otiun 146 artificial log 146

Logarithmic amplifier 127

M,,gnetrun I?. 38. X I action 84 c~~nalruction 83 operation frrqusncy X i psckicgcd 84 stnq,ping 87 time dclay st hwitch~on 84 rvorking life cxpectartry 88

Mastcr~Slave interswitch conf~guration 163, I64

Maths cr,prc,cL.ssol 154 klarimurn range 32

calculatioll 22 Mclnclry mappins 158. IhO MIIIL.~ effect 41 Minimum rilrlss 21. 311

calculation 22 Mininrum rcccivrd sign:ll lrvcl

hl

M i r r r l a ~ s 118. 1211 hnlance<l 120

Morlulatc,r 12.35. 75 charpcidischargr lrigger

pulhe~ 1.1.35.18 remnant choku charping 75 hold-ofldi ,~lc 76 sfiti~rahlc care reactor time

riel;~y 78 pri~rring network 79 pi~lsc length witching 74

Multiple schocs 55 Multiplc lcvcl video 132, 158

N:turical niile 5 Noise 10. 61

fipuri. 125 in local oscillalor I20 I" receiver 124 minimisation with balanccd

mir r r 125 Nurth itabiliscd dibplay 29. 144 Numher of cchoes rcttlrnrd 24.

33 c;~lcl~l;ltian 25

Operation uf basic prllrr radar 13

Open wiru feeder 63 Opticill horizon 12 Ovcrall pcrf<,rmancc monitor

I06

Peak k>owcr 17 effects of chaop~ng 14

Prdcsa l voltagc wavelorrn 1111 Pcrlormitncc rnanitor 3 6 4 3 .

102. 1113 analysis of results lflh coupling 1114 ringing time 1115 Luning 101. Ill6

Phase vclucity 91 Pixel 159 Prr-IF A~l>plilirr 40 Prec~pilation iluttcr 42. 53 PRF gcncratur 1 I. 35 Plan Pilsitio~l Indicator (PPI) 7 Plume display of power m o n i t ~ ~ r

ill.? Priming network 79 Propagation 01 rada! wnvec 47 Prop:~dfion modes in

w;ivrguide 91 Powrr. effect on milximum

range hl Poacr monitor 101

display of result 103 Plop;tgiltion of radar waves 47

\landard pn>pagatio,l conditions 47

Pulse durafton I6 lor short rangcs 16

lor lunx rangcs I h Pulse forming r,ctwurk 71 Plllrr Irogth &witching in

modulator 79 Pol~r repetition frequency (pro

16.23 cffecta olchanging 34 lor short ranee- 12. I6

synchnmiard 35 Pulhc rrpctition period (prp) 16 I'olsc u~iilth - clfccts of

O facurr of resonant cavity Oilnl-tcr KBYC rnulallic insulatrrr

8'9

Rilc<,n 168 R;<dar ilitcrfcrencr 5.1 K;>d;lr h o r i ~ o o 29. 32

calculation of 2'1.32 Radar milc 5 Ilndar rcHectr,rs I65

ocvilhcdral cluster lhh pentagonal cluster I66

K ; ~ d i ; ~ t i n g ~ l ~ ~ l s 96 Rain clutter 12.53. 124 Rain. cifccr* 01 5 1

cifrcts on X and S hand 52 Kange diacriminarion 18

~ i l l~~ ! l a t i on 14-21 Ksngc gate 112 Range crrsasurcrncnt 4 Ilanpc rings 4 Range ring generator 41.33.3.5 Ilastcr 155 Ri~s l r r >can display 24, 155

rolour rli\pli~y 156 crl lor raster scan 156 dc t lcc t io~~ system 158 memory mapping 158 \~.anniog principles I55 video for raster scan 158. Ihll

Rifitlacc 121 Knwvi<lcc 13. 130 Read p t c 132 Kcccivcr 13, 124

ilulornntic flsqucllcy contr,ll 12Y

hilndwidth 124. 120 log~ri thmic amplifier 127 noise 124 swept pain 130 vlrieo detector 129 video limiter

Hcncction cocificient~,ltargst 60

Rcfisction of nrrlar ur:n.rs 47 super refractior, 48 suh rcfractirln 40

Relative motion 143

246 Index

Rerct radius 153 Resolvcd tide for true motion

152 Resonant cavity 82 Resonant choke charging 75 Kcsonantfrequency 81 Resonant termination of

scanner 99 Resting period 16 Retimed video 131 Rotating deflection coil hcaring

transmission system 107 Rotatingjoint 94

'S' (IIIcm) lrequency band 17 comparison with 'X' (3 cm)

hand 163. 164 SART 3. 170 Saturahlr core reactor

modulator timc delay 78 modulator discharge switch

79 Sawtooth current 13, 140

production by timehasr generator 141

Scaling amplifier 146. 149 Scanner 6, '36 Scanner

beamwidth measurement 98. 101

construction 99 effect on minimum range 31 cffrct of changing height 33 cffect of changing vertical

beamwidth 33 cffcct of changing magnctmn

lrcquzncy 100 hcight 29 gain IUU installntion 101 maintenance 101 radiation charilctrristics 5, 6 radti~tion lest 38 rotation 6, 8 rotiltianal speed 6, 8,28, 33 s idc lohe~ 98, 101 siting 55. 56 slotted waveguide lypc 39 s<l"iinl 100 termination 99

Scrccn persistency (ppi displays) 28.33

Sea clutter 29.41.52 Second trace echo 23

calculation 23 swept prf to nlinimise rflcct

24 Scomdary Radar 168 Shadow mask tube 157 Shadow sectors 56 Shift 130 Ship's hrild up display 28, 143

Side lobcs YX Sidc lohe effects 53 Signal-Noise ratio 18.61 Sinc-cosinc look up rahles 159 Sine-cosinr p<,tcnliomctcr Sine-cosine resolvcr lll8 Skew ilnglr 98

altcrtlatc skcw Y Y Sleet, effects of 51 Slot antcnna 96 Snow. rffcctsnl 51 Speedlog 146 Spurious echocs and rflccts 52 Stahilissd display 144 Stationary deflection coil

bearing transmission 107 Sun pattrrn lrnm performance

monitor 105 Suner refraction 48 Swept gain 41, 130 Syn the t~cv~deo 155,160

Target area 59 Target direction dctcrminatiun 5 Target distortion 28 I'argct range determination 5 Thyristor switch 38.77, 78 Threshold potential 131. 132 Tide corrrcti<m for true motion

151 in-line tide 151 rcsolvcd tide 152

sawtooth current gcncration 141

synchnmiaation in analogue display 8.72. 142

Timehase generator for raslrr scan display 158

TB ccll 39. 115 Trilnhcrivrr 12 'lrensmitrcr hrcak-rhmugh 15,

19 Trapezoidal waveform 45 Tropospherc 47 TRswitch 12 TRczl l 12,22.38.41. 113

attenuation of signal 113 bandwidth 113 construction 113 insertion loss 114 kcep alive volrage 1 13 keep alive current 114 tunehlc cclls 115

Trilnsmissinn lines 63 artificial transmission lines 71 characteristic impedance 65

cillculation of 73 A C operating conditions h9

L)C operating a,nditions 66 loss free 64 uncd as pulsc forming

network 73 time dclay 72 cillculilti<,n 73 velocity of propagation 66

Transmitter 12 Trsnsmittcd pulse duration 18 Trapping o l radar naves 49 True motion 146

dig~till 153, 160 resolver 148 qcallng 146 tide correction 151

Unstabiliscd display 111

Vilractor diodc limiter 113 Var~ablc Rangc Marker (VRM)

9.43.44.45 Veloclty ot propagatton of F M

wave 4 Vcrtical hcamwidrh 6 ,30 .33

rffccl on minimum range 31 effcct whcn vcssel is mlling

3 l Video 129

amplifier 43 correlated 134 dlgital 131 limiter 129 mixer 43 lor raster scan display 158 raw 13. 130

Waveguide 12,38.89 bcnds, E and H planc 94 L.urrrnt distribution in

wavcguidc wslls 93 reactance diaphragms 95 development from

transmission linc 89 excitation 90 flexihle 94 joints 93.94 prcssuriard waveguide 95 propagation within

waveguide 91 ntfr windows 95

rotalingjoint 94 test for passage of rf encrgy

?R windows 95

Wavelength 5 in relation trr scanner

dimension 5 lor 'X' and 'S' band 6 in waveguide 91

'X' (3 cm) frequency hand 17 comparison with 'S' hand

163. 164