Introduction to Avionics

Microwave Technology Series The Microwave· Technology Series publishes authoritative works for professional engineers, researchers and advanced students across the entire range of microwave devices, sub-systems, systems and applications. The series aims to meet the reader's needs for relevant infonnation useful in practical applications. Engineers involved in microwave devices and circuits, antennas, broadcasting communications, radar, infra-red and avionics will find the series an invaluable source of design and refer­ence infonnation.

Series editors: Michel-Henri Carpentier Professor in 'Grandes Ecoles', France Fellow of the IEEE, and President of the French SEE

Bradford L. Smith International Patents Consultant and Engineer with the Alcatel group in Paris, France, and a Senior Member of the IEEE and French SEE

Titles available

1. The Microwave Engineering 5. Infrared Thermography Handbook Volume 1 G. Gaussorgues Microwave components Edited by Bradford L. Smith and 6. Phase Locked Loops Michel-Henri Carpentier J.B. Encinas

2. The Microwave Engineering Handbook Volume 2 7. Frequency Measurement and Control

Microwave circuits, antennas and Chronos Group

propagation Edited by Bradford L. Smith and 8. Microwave Integrated Circuits Michel-Henri Carpentier Edited oy L Kneppo

3. The Microwave Engineering 9. Microwave Tube Transmitters Handbook Volume 3 L. Siran microwave systems and applications Edited by Bradford L. Smith and

10. Microwave Electronic Devices Michel-Henri Carpentier Theo G. van de Roer

4. Solid-state Microwave Generation J. Anastassiades. D. Kaminsky. E. Perea 11. Introduction to Avionics and A. Poezevara R.P.G. Collinson

Introduction to Avionics

R.P.G. Collinson BScEng., CEng., FIEE., FRAeS

Formerly ofOEe Marconi-Avionics Ltd, Rochester, Kent, UK.

I ~ rt1 SPRINGER-SCIENCE+BUSINESS MEDIA, B.Y.

First edition 1996

© 1996 R.P.G. Collinson Originally published by Chapman and Hall in 1994

ISBN 978-94-010-4007-5 ISBN 978-94-011-0007-6 (eBook) DOI 10.1007/978-94-011-0007-6

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The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made.

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Contents

Foreword Preface Acknowledgements

Introduction 1.1 Importancc and role or avionics

I. I. I Systcms which interrace directly with thc pilot I. 1.2 Aircraft statc scnsor sYstcms 1.1:1 Na\igation systcms I. 1.'+ Extcrnal \\ orld scnsor systcms 1.1.5 Task automation sYstcms

1.2 Thc avionic cmironmcnt 1.2.1 Minimum \\cight 1.2.2 Environmental rcquircmcnts 1.2.:1 Rcliability

2 Air data and air data s~stems 2.1 Introduction 2.2 Air data information and its usc

2.2.1 Air data measurcmcnt 2.2.2 Thc air data quantitics and thcir importancc

2.\ Dcri,ation of air data laws and relationships 2.,.1 ChOICC orulllts 2.,.2 2 .. ~. ") 2.' . .+ 2._~.)

2:1()

2.,7 2 . .1.X

Altitudc-static prcssurc relationship Variation of ground pressurc Air dCl1Sit~ \s altitudc relationship Spccd of sound dcri\ation Pressurc-specd relationships Mach number Calibratcd airspccd

2.:1.() Static air tcmpcraturc 2, J() Truc airspced 2 . .1. I I Prcssurc crror

2.'+ Air data sensors and computing 2.'+.1 Introduction 2.'+.2 Air data systcm prcssure scnsors 2.'+.:1 Air data computation

Xl

Xlii

X,·

1.+ 1.+

16 16

16 16 IX

.+1

.+2

.+2

.+2

.+.+ 52

vi ( 'on tents

2.-1-.-1- Angle of incidence sensors 55 Further reading 56

3 Aerodynamics and aircraft control 57 :U Introduction 57 :U Basic aerodynamics 57

:U.I Lift and drag 57 :U.2 Angle of incidence/angle of attack 5<) :U.:I Lift coefficient and drag coefficient 5<) :1.2.-1- Illustrative example on basic aerodynamics 62 :1.2.5 Pitching moment and aerodynamic ccntre 65 :1.2.6 Tailplanc contribution 6-1-

:1.:1 Aircraft stability 6() :1.:1.1 Longitudinal stability 66 :1.:1.2 Aerodynamically unstable aircraft 6X :1.:1.:1 Body lift contributions 70

:1.-1- Aircraft dynamics 71 :1.-1-.1 Aircraft axes - yciocity and accleration componcnts 71 :1.-1-.2 Euler angles - definition of angles of y'l\\. pitch. bank 7-1-:1.-1-.:1 Equations of motion for small disturbances 76 :1.-1-.-1- Aerodynamic force and moment derivatives 7<J :1.-1-.5 Equations of longitudal and lateral motion XX

:1.5 Longitudinal control and response <J2 :1.51 Longitudinal control <J2 :1.5.2 Stick force/g <):1 3.5.1 Pitch rate response to tailplane/cievator angle 9-1-:1.5.-1- Pitch response. constant forward speed 96 :1.55 Worked example on q/ '7 transfer function and pitch 10-1-

response :I.() Lateral control 107

:1.6.1 Aileron control and bank to turn 107 :1.6.2 Rudder control 110 :1.6.:1 Short period yawing motion 110 HJ.-I- Combined roll-yaw-sideslip motion 112

:1.7 Auto-stabilisation systems 112 :1.7.1 Limited authority auto-stabilisation systems 112 :1.7.2 Full authority auto-stabilisation systems 117

Further reading IIX

.. Fly-by-wirc flight control 119 -1-. I Introduction 119 -1-.2 Fly-by-wire flight control 120

-1-.2.1 FBW system basic concepts 120 -1-.2.2 Advantages of FBW control 127

-Ll Control laws -l.l.1 Pitch rate command control -l.l.2 Roll rate command control -l.l.l Modern control theory

-l.-l Redundancy and failure sur\"ival -l.-1-.1 Safety and integrity -L-1-.2 Redundancy configurations -l.-1-.3 Voting and consolidation -1-.-l.-l Quadruplex system architecture -l.-l.5 Common mode failures -1-.-1-.6 Dissimilar redundancy

-1-5 Digital implementation -l.5.1 Advantages of digital implementation -l.5.2 Digital data problems -l.5.3 Software -l. 5.-l Failure modes and effects anal~ sis

-l.6 Fly-b)-light flight control -l.6.1 Introduction -l.6.2 Fly-by-Iight control systems -l.(,.l Optical sensors

Further reading

5 Inertial sensors and s~'stems 5.1 Introduction 5.2 Gyros and accelerometers

5.2.1 Introduction 5.2.2 Angular momentum gyroscopes 5.2.3 Optical gyroscopes 5 2 -I- Accelerometers

5 .. , Attitude/heading reference systems 5 .. ,.1 Introduction 512 Stable platform systems 5.l.l St rap-dO\\l1 systems 5.". -l Alignment and monitoring

Further reading

6 N ayigation s~stems 6. I Introduction and basic principles

6.1.1 Introduction 6.1.2 Basic n,l\'igation definitions ().1.3 Basic DR navigation systems 6.1.-l Brief overview of Doppler radar velocity sensors

6.2 Inertial navigation ().2.1 Introduction

( 'unlclIl., \11

III 13(,

1-1-5 1-1-6 1-1-7 1-1-7 1-1-X 1-1-'.1 15-1-15-l 155 157 157 15'.1 1(,2 16'.1 170 170 171 17-l 176

177 177 In In 179 IX7 20-l 210 210 211 21-l 223 2-1-5

2-l(, 2-l(i 2-1-6 2-lIJ 253 256 25,) 25'.1

VIll Contents

6.2.2 Basic principles and Schuler tuning 260 6.2.3 Initial alignment and gyro compassing 269 6.2.4 Effect of azimuth gyro drift 272 6.2.5 Vertical navigation channel 273 6.2.6 Choice of platform axes 276 6.2.7 Choice of navigation co-ordinates 278 6.2.8 Strap-down IN systems 279 6.2.9 Aided IN systems and Kalman filters 280

6.3 GPS - global positioning systems 289 6.3.1 Introduction 289 6.3.2 GPS system description 290 6.3.3 Basic principles of GPS 292 6.3.4 Integration of GPS and INS 297

6.4 Terrain reference navigation 299 6.4.1 Introduction 299 6.4.2 Terrain contour navigation 300 6.4.3 Terrain characteristic matching 301 6.4.4 Civil exploitation of TRN 301

Further reading 302

7 Displays and man-machine interaction 303 7.1 Introduction 303 7.2 Head up displays 304

7.2.1 Introduction 304 7.2.2 Basic principles 308 7.2.3 Holographic HUDs 314 7.2.4 HUD electronics 321 7.2.5 Worked example on HUD design and display 324

generation 7.3 Helmet mounted displays 328

7.3.1 Introduction 328 7.3.2 Helmet design factors 328 7.3.3 Helmet mounted sights 330 7.3...1- Helmet mounted displays 331 7.3.5 Head tracking systems 335 7.3.6 HMOs and the virtual cockpit 336

7.4 Discussion of HUDs vs HMOs 339 7.4.1 Introduction 339 7.4.2 Civil aircraft HUDs 339 7.·U Military aircraft HUDs and HMOs 342

7.5 Head down displays 342 7.5.1 Introduction 342 7.5.2 Civil cockpit head down displays 343 7.5.3 Military head down displays 347

7.5.-l Raster overlay display generation 75.5 Digitally generated colour map displays

7.6 Data fusion 7.7 Intelligent displays management 7.8 Displays technology

7.8.1 HUD displays 78,2 Head dmm displays

7.9 Control and data entry 7.9.1 Introduction 7.9.2 Tactile control panels 7.9.3 Direct voice input 7.9.-l Eye trackers

Further reading

( 'oll/l'llls

3-l7 3-l8 1-'" . :u ]5]

356 356 356 359 359 360 361 362 365

8 Autopilots and flight management systems 366 X.I Introduction 366 X.2 Autopilots 367

8.2.1 Basic principles 367 8.2.2 Height control 368 8.2.3 Heading control autopilot 370 X.2.-l lLSIMLS coupled autopilot control 380 X.2.5 Automatic landing 3X6 8.2.6 Speed control and auto throttle systems 392

X.3 Flight management systems 393 X.3.1 Introduction 393 X.3.2 Flight planning :\<)5 X.3.3 NaYigation and guidance 399 X.3.-l Flight path optimisation and performance prediction 399 ~U. 5 Control of the yertical flight path profile -lOO 8.3.6 Operational modes -l02 8.3.7 -lD flight management -l03

Further reading -l05

9 Avionic systems integration -l06 9.1 Introduction and background -l06 9.2 Data bus systems 413

9.2. I Electrical data bus svstems -l13 9.2.2 Optical data bus systems -l19

9.3 Integrated modular avionics -l27 Further reading -l30

Glossary of terms List of s~;mbols List of abbreviations Index

-l31 -l38 -l-l7 H9

L\

Foreword

Avionics covers the diverse topics of computing, electronics. control and communications. The dramatic advances in these disciplines in recent years havc been succcssfully applied to aircraft systems including flight control and guidancc systcms. aircraft navigation, displays, fault tolerancc. sensors and monitoring. In the systems engineering approach to dcsign. the system designcr needs a sound grasp of the principles of operation of avionics systems. an understand'ng of signals and error sources and knowledge of aircraft systcms to be able to dcsign. develop and integrate aircraft systems.

Dick Collinson' s book brings thcse threads together. It is a difficult task to cO\cr navigation systems. displays. flight control and the related topies which underpin the operation of modern civil and military aircraft. The author brings kno\\ledge of avionics systems design based on his close involvement with many of the major international aircraft projccts of recent years. His rigorous treatment of topics which are difficult to extract from the literature and his insights into the systcms design approach make this book a fresh and useful addition for engineers in industry and for university courses covering aeronautical systems engineering.

This book is appropriate for the aeronautical engineer wishing to understand aircraft systems, for the electronics engineer needing to grasp the fundamentals of flight dynamics and navigation and for the control engineer who lacks knowledge of aircraft operation and aircraft systems. Although the book is ambitious in attempting to cover a very wide range of topics in modern avionics. Dick Collinson has managed to bring a practical perspective to many othemise dry and thcoretical topics. His approach has a sufficient blend of rigor and practical discussion to scnc as an essential reference for designers. manufacturers and operators of modern avionic equipment.

Professor D. 1. Allerton Head of Department of Avionics. College of Aeronautics. Cranfield University. United Kingdom.

Preface

My reason for writing this book is to meet the need for a graduate level text book which explains the basic principles underlying the key avionic systems in a modern civil or military aircraft from a systems engineering standpoint. and their implementation using modern technology.

A particular aim. based on my experience over many years. is to meet the needs of graduates (or equivalent) entering the avionics industry who hme been educated in a wide variety of disciplines. for example. electronic engineering. computer science. mathematics. physics. mechanical and aeronautical engineering. The book also aims to meet the needs of engineers at all levels working in particular areas of avionics who require an appreciation and understanding of other areas and disciplines and the latest technology implementations.

A further objective is to show the \'e~ wide range of disciplines "hich arc involved in avionic systems. as this makes the subject an interesting and challenging field. Apart from the interest inherent in aircraft. the range of disciplines and technologies which arc exploited covers satellite navigation. optical gyroscopes. man~machine interaction. speech recognition. advanced display systems. holographic optics. intelligent knowledge based systems. closed loop control systems. high integrity failure survival systems. high integrity software. VLSI design and data bus systems.

The technology used to implement avionic systems is subject to a process of continual change as improved performance and lower cost is sought. Ne\\ technologies and systems which offer significant imprmelllents arc introduced mer relatively short time scales "hich. in fact. arc tending to get shorter particularly in respect of electronic implementation and integrated circuit technology.

The basic philosophY adopted in this book has. therefore. been to concentrate 011

the underhing principles and basic theon imolved in the avionic sYStems as this is unchanging. The latest means. however. for implementing the mionic systems hme been explained Future technologies and systems which arc still in the advanced de\cloprnent stages and not yet in senice ha\e been revie\\ed. My recent background and responsibility for advanced avionic systems research has also enabled me to comment from the basis of first hand experience.

Personall). I have found avionics a fascinating subject throughout my career and I hope the reader will be able to share this interest.

Dick Collinson July 1995

Acknowledgements

I would like to thank the management of GEC-Marconi Avionics Ltd .. Rochester for their assistance in writing this book and their permission to use a number of the illustrations showing GEC-Marconi Avionics systems and concepts. In particularly. I would like to express my appreciation to Brian Tucker. Director and General ManageL and Robin Sleight. Director of Marketing and Technology of the Displays and New Ventures Division. for their encouragement and assistance. I would also like to thank my former boss. Ron Howard. formerly Managing Director and later Chairman of GEC Avionics (now retired) for his help and encouragement. My thanks and appreciation to my fonner colleagues in the Company. Chris Bartlett. Gordon BelcheL John Corney. Andrew Gibson. Derek Hamlin and Dme Jibb for their help in obtaining information. checking the draft chapters and providing helpful and constructive comments.

I \\ould also like to thank Professor David Allerton. of Cranfield University for his help and support.

My thanks and appreciation also to Peter Potocki. Department Manager/Cockpit Avionics. and Gerard PeilleL Senior Engineer/ Automatic Flight Systems of Airbus Industrie for their advice and assistance on flight management systems.

The excellent \'\ork carried out by Bob and Jean Ellwood and Andy Poad in producing this book is gratefully acknowledged. Bob and Jean for producing the typed and formatted text including all the equations to the 'camera ready copy' stage and Andy for producing most of the computer-generated illustrations from hand drawn diagrams.

Grateful ackno\\1cdgelllent is made to the follo\\ing companies for permission to lise their illustrations.

Airbus Industrie. British Aerospace Defence Ltd. GEC -Marconi Avionics Ltd. GEC -Marconi Defence Systems Ltd. Litton Industries. Canada. Lockheed Advanced Development Company. Rockwell International. Collins Avionics Division. Schlumberger Industries. Smiths Industries.

Finally. I would like to thank my wife and family for their whole-hearted support and encouragement in \"riting this book.