Electronic Aids to Navigation

L. Tetley T. Eng., F.S.E.R.T., M.R.I.N.

D. Calcutt M.sc.c.E~~.,M.I .E.R.E.

Senior Lecturers Faculty of Technology Southampton Institute of Higher Education

~ d w a r d Arnold

Contents

Preface

Acknowledgements

1 Sonar Navigation I . 1 The characteristics of sound in sea water 1.2 The transducer 1.3 The echo sounder 1.4 An echo sounding system 1.5 Echo sounder apparatus display systems

2 Speed Measurement 2.1 Introduction 2.2 The electromagnetic speed log 2.3 The pressurr tube log 2.4 Acoustic correlation log 2.5 Doppler speed measurement 2.6 Simrad NL Doppler speed log 2.7 The Kmpp Atlas 'Dolog' speed logs

3 Decca Navigator 3.1 System principles 3.2 Transmission frequencies 3.3 Lane width 3.4 Zones and centilanes 3.5 Lane identification 3.6 Multipulx lane identification 3.7 The receiver 3.8 Decca chains 3.9 Decca frequencies 3.10 Accuracy 3.1 1 Decca charts 3.12 Position fixing 3.13 Mark 21 receiver 3.14 Track plotter

J 4 Loran-C 4.1 System principles 4.2 Loran tines of position (LOP)

i 4.3 Loran-A

s c,

?

viii Contents

4.4 Loran-C 4.5 Loran-C charts 4.6 Loran< Lattice tables 4.7 Position fixing using the Loran-C system 4.8 Loran-C coverage 4.9 Loran-C receivers

5 Omega 5.1 Introduction 5.2 System principles 5.3 Signal format 5.4 Lane identification 5.5 Omega propagational performance 5.6 Omega skywave correction tables 5.7 Lattice tables 5.8 Accuracy 5.9 Omega transmitters 5.10 Omega receivers 5.1 1 The Redifon NVI Omega Navigation Receiver 5.12 Differential Omega 5.13 Range range mode

6 Navigation by Satellite 6.1 Introduction 6.2 Basic satellite theory 6.3 The navy navigation satellite system (NNSS) 6.4 The transit satellite 6.5 Errors 6.6 Microproce%sor wntrolled satellite navigation receiver 6.7 Usine a satellite navigation receiver 6.8 ~ a c i Decca's DS4 ~itellite Navigator 6.9 Global positioning system, ~ a v s t a r 6.10 Navstar user equipment

7 Integrated Navigation System 7.1 Introduction 7.2 Concepts of integrated navigation 7.3 Satellite navigation plus Omega integration 7.4 Total integration

8 Tbe Ship's Compass 8. I The gyrocompass 8.2 Compass errors 8.3 Principle of the Sperry SRI2O gyro compass apparatus 8.4 Speny SR22O gyrocompass 8.5 Principles of the S.G. Brown MK. I Model 5 (C) gyro compass 8.6 Compass repeaters 8.7 The Magnetic repeating compass

9 Antonutic Steering 9.1 Introduction

Proportional control Derivative control Integral control Basic autohelm Manual operator controls Overshoot Phantom rudder The adaptive autopilot

10 Radio Direction Finding 10.1 Introduction 10.2 Radio waves 10.3 Antenna 10.4 Sense determination 10.5 The Bellini Tosi system 10.6 An automatic direction finder using a servo system 10.7 An automatic direction finder using a microprocessor

Appendix 1 Radio waves, propagation and the ionosphere Appendix 2 Doppler Effect Appendix 3 Zilog 280 Terminology Appendix 4 Glossary of microprocessor and digital terms Index

Conrenrs ix

x.

A&- correlation log, 35 Acoustic~hve. 3 Adaptive autopilot. 309

confined waters mode, 31 1 display, 314, 315 eyed ki bur, keeping, 310 system diagram. 312. 316

ADC (Analog to Digital Converter), 346 ADF (Automatic Direction Finder). 329. Algorithm, 346 ALPHA transducer, 42 Altitude error, 205 Angular momentum. 249 Antenna,

direction finding. 319 height error, 205 satellite navieation. 219 -

Apogee, 188 A X 11. 346 ASF (Additional Secondary Factor), 95 Attenuation, I Auto alarm, 333 Auto correlation, 35, 235 Autohelm, 298 Automatic RDF. 330, 334 Auto steering,

adaptive autopilot, 309 basic svstem. 302 derivahe control, 300 follow-UD (FU), 306 integral control, 301 non follow-up (NFU), 305 operator controls, 305 overshoot, 306 phantom mdder, 308 proportional control, 299 weather control. 305

Admuth. 188 ,Admuth drift. 253

Ballistic errors, 267 Bandwidth, 229 BCD (Binary Coded Decimal), 16, 347

Reamwidth, I I Rellini Tosi system, 323

92 , .... u ~ c , , 206 E&":- om - tracking speed, 46

Cathode ray tube, 85 CA (Coarse and Acquire) code, 227 Clarinet Pilprim. 106 - .

334 Clcck timer chip, 224 Coastal refraction. 328 Codes, 227 Compass, 248

errors, 265 gyro, 248 magnetic. 290 repeaters, 285

Controlled gyro compass, 254 Correlation log, acoustic, 35 Course error. 268 CPA (Closest point of approach), 198 CPU (Central Processing Unit), 348 CW Mode, 44 Cycle matching, 94

DAC, (Digital to Analog Converter), 349 Daisy Chain, 222, 348 Damping, 256 Data,

display, 246 message, 196 phase modulation, 195 stripping, 223 transmission, 227

Deadband, 306 Decca Navigator, 55

accuracy, 64 chains, 64 charts, 67 dewmeters, 55 discriminator. 62 errors, 67 fundamental frequency, 58 inter-chain fixing, 78

353

354 Index

Decm Navigator (conld.) lane, identification, 60 lane slip. 79 lane width, 59 multipulse LI, M) operation. i 7 position fixing, 71 receiver, 61 skywave reception, 66 System principles. 55 track plorrcr, 79 transmission frrqumcies. 57 zones, 59

&Ilini Tosi system, 323 errors, 324 loop, 321 microorocessor ADF. 334 null, j22 radio waves. 318 sense, 322 servo ADF. 329

Differential Omega, 182 Displays, 16 Distance integration, 25, 30, 37, 49 Doppler effect, 342

frequency shift curves. 199 speed measurement, 37

Doppler spxd lo& 45 Kmpp Atlas Dolog. 50 Simrad NL. 45

Drift, 252 Dynamic Error. 266

Echo sounder, 10 digital circuits. 13 display systems. 16 PRF @ulse repetition frequency), I I pulse length, LO

EHF (extreme high frequency), 342 Electromagnetic,

principles, 22 speed log, 22 transducer, 24

Electrostriction. 6 Electrostrictive transducer. 6 Envelope matching, 85 EPROM. 349 Errors.

Decca navigator, 67 direction finder, 325 gyrocompass, 265 Loran-C, 101 Omega. 145

Satellite navigation. 201 Excitation factor. 144

Flag, 349 Fleming's Right Hand Rule, 22 Flux gate. 290 Flywheel oscillator, 72 Follow-up (FU), 306 Follow-up systems, 261 Free gyroscope, 248 Frequency,

Oecca navigator, 57 direction finder, 3 18 echo sounding. I Loran€. 85 Omeea. 137

Geodetic error, 201 Geometric contours, 117 Geophysical parameters, 147 Global Positioning System (GPS),

codes, 227 data. 227 errors, 230 navigation fix, 230 pseudo-range, 230 system overview, 226 user equipment, 232

Gravity field error, 204 Ground segment (NNSS), 193 Gyrocompass, 248 Gyropilot. 298 Gyroscope, 148

controlled, 254 damping, 264 drift, 252 ;

errors. 265 free. 248 gravity control, 256 north seeking. 255 north settling, 256 repeaters. 288 tilt, 253

Hex gate, 349 H F (high frequency), 341 Hyperbola, 56 Hyprbolic navigation system. 55

Inertia, 249 Integral control, 301 Integrated navigation systems. 237

concepts. 237

Index 355

data display, 246 Omcga/NNSS. 239 Iotal integration, 242

knus transducer, 41

,@pier's Laws. 188 /~oden LR707 Loran-C equipment. I21

[Lane identification. 1 D.=a,60 ; Omega, 141 !lane slip, 79 /latitude error, 267 iLe $ - d i ~ 1 ~ ~ l E ~ , , HI iline of position (LOP). 55 'Lncar momentum. 249 l~odestar ADF, 329 bran, 81

sd.Wqal secondary factor (ASF). 96 blink, 92 cham. 95 1. ..~ .... clarinet Pilgrim, 106 -. --.. correction tables, 95 .... ...

coverage, I02 cvcle matchinn. 94 emission consiraints. 90 envelow matchina, 85 - frequency, 85 geometric contours, 11 7 lattice tables, 98 lines of position (LOP), 81 Loran-A, 85 Loran-C, 87 Loran-C receivers. 119 notch filters. 119 phase coding. 91 position fixing, 106 pulse groups, 89 pulse to pulse ECD tolerance. 90 pulse to pulse timing tolerance, 91 pulses, 87 root mean square error, 114 skpvave reception, 93 skywave correction tables, 100 system principles, 81

lSI (large scale integration), 17

Magnavox 1102 recetver. 210 Magnavox 1105 receiver, 239 '~agnettc repeattng compass, 290 [~agnetometer. 291 Mametostnction, 7 ~agnetostnctive transducer, 7 Manoeuvring error, 267

....

Marconi Marine ADF, 329 ''...--- Marconi Marine Seahorse, 12 M F (medium frequency). 341 Microproccswr,

autopilot, 31 1, 314 ADF, 384 integrated navigator. 204 LoranC receiver, 119 satellite navigation receiver, 221, 232

Modulation codes, 227 MPU (Microprocessor unit), 350 Multipulse L1 (Decca). 60 Mutual interference. 145

I*nvsmr satellttemsyigation, 225 codes 227 data. 227 . --_ errors, 230 navigation fix, 230 ovemew, 226 pseudo range measurement, 230 user equipment, 232

Navy Navigation Satellite System (NNSS), 190 data message, 196 errors, 201

... ground segment, 193 '' na~,,gation fix, 197

operation, 21 7 self test, 214 space segment. 193

Newton's laws of motion, 249 Night effect, 327 Noise. 3 Non follow-up, 305 North seeking gyro, 255 North settling gyro, 256 Notch filters. 119 Notices to mariners, 65 Nova satellites, 159 Null, 322

Omega, 137 accuracy, 160 arctic paths, 148 attenuation, 144 auroral zones. 148 charts. 148 coverage, 138 d~fTerential Omega, 182 excitation factor, 144 frequency. 137 geophysical parameters, 147 hyperbolic lattice. 140 interpolatton, 151 lane identification (LI). 141 lattice tables. 157

Omega (confd.) LOP recorder, 174 m u l d interference between modes, 145 phase velocity, L45 golar cap absorption IPCA). 147 propagarionst performance, 143 range-range mode, 185 receivers. 167 signal format, 141 skywave correction tables, 148 sudden ionospheric disturbances (SID), 147 system vrinciules, 137

loop, 321 microprocessor ADF. 334 null, 322 radio waves. 3 18 m s e , 322 servo direction finder, 329

Radiowaves. 318. 340 Radux system, 137 RAM (Random A~xess Memory), 351 Range-range mode, 185 Rediffusion NVI Omega receiver. 168 Refraction error, 202 R ~ i n ~ ~ n t y error, 232 RMS e::~:. 1 !J Rolllng error. 166

data, 188 Rotating = + & @ + I penod. 189

precession. 192 -.xelorrry. 188

Ovsrshoot. 306

Pendulum, 283 Perigee. I88 Permanent helm, 304 Phantom ring, 271 Phantom rudder. 308 Phase coding, 91 piezo ceramic transducer. 35 Piezo electric resonator. 7 P~tot log, 27 Polar cap absorption. 147 Polar diagrams, 320 Polarization error, 327 Power dlstnbution curves, 229 Precession, 250

gyro, 280 orbital. 192

Pressure tube log, 27 PRBS (vseudo random binary sequence)

codes, 235 pRF (pulse repetition frequency), I I ~ R N , (pseudo random noise) codes. 227 Propagation, 340 Prowrtional control. 299 ~se;do range, 230 Pulse groups, 89 Pulse length, 10

Quadrantal error, 235

Racal Decca. autonilot DP780. 314 sateliite navigator DS4. 218

Radio direction finding, 3 18 antenna, 319 Bellini Tosi system, 323 errors, 324

SAL ACCOR speed log. 35 SAL Jungner log, 30 Salinity, 2 Satellite,

birdcage orbits, 191 blocking, 206 data stripping. 223 dopplcr curve, 199 earth segment. 192 errors. 201 frequency stability, 229 message. 195 navigation, 186 Nova, 159 parameters. 186 slant range change. 200 space segment, 194 Transit, 193

Sea bed consistency. 2 Seahorse echo sounder, I2 Self test. 214 Semi circular error, 326 Sense determination. 322 servo. 330 S. G . Brown MK.1 gyrocompass. 277 SHF (super high frequency), 341 Sh i~ ' s compass. 248 Signal to noise ratio, 5 Simrad NL doppler log, 45 Skywaves. 66, 93. 148 Slant range change, 198 Sonar navigation. I Sound in sea water. I Speed.

error. 268 logs, 22. 27. 35, 37 measurement. 2 1 vectors during manoeuvres. 51

Sperry Ltd.. SR120 gyrocompass. 270 SR220 gyrocompass, 174 SRP2000 autooilot. 310

STC Automatic DF, 334 Stepper motors. 289 Stepper repeaters. 289 Subroutine, 352 Sudden ionospheric disturbance (SID). 147 Synchro repeaters, 289

Thomas Walker speed log, 26 Tilt. 253 TO& integrated navigation sys&, 242 Track plotter. 79 Transducer,

ALPHA, 42 echo sounder, 5 electromagnetic, 22, 27 electrostrictive, 6 Janus, 41

magnetostrictivc, I

piew ceramic, 35 siting. 9

Transmission errors. 265 Transit satellites, 193 Tropospheric refraction, 202

UHF (ultra high frequency).341

Velocity error. 207 Vertical effect, 328 VDU (visual display unit), 20 VHF (very high frequency). 341 VLF (very low frequency), 137, 340

Water tracking speed. 45 Weather control, 305 WGS 72, (World Geoidal Survey 1972). 204

280 terminology, 344 Zilog 280 microprocessor, 222