Flight Simulation Software

David Allerton is an Emeritus Professor at the University of Sheffield and Visiting Professor for Flight Simulation at Cranfield University, UK. He is currently a consultant to CnTech, a global developer of flight simulation software. Professor Allerton was a member of the Royal Aeronautical Society (RAeS) Flight Simulation Group for 25 years, serving 2 years as its chairman. He is the author of Principles of Flight Simulation.

• Preface xiiiAerospace Series Preface xviiGlossary xixAbout the Author xxiiiAbout the Companion Website xxv1 Design of an Engineering Flight Simulator 11.1 The Evolution of Flight Simulation 11.2 Structure of a Flight Simulator 31.3 Real-time Flight Simulation 61.3.1 The Concept of Real-time Computing 61.3.2 Operating Systems 81.3.3 Latency 91.4 Distributed Computing 101.5 Processes and Threads 151.5.1 Multi-tasking 151.5.2 Semaphores 161.5.3 Asynchronous Input 181.5.4 Real-time Scheduling 211.6 Software Partitioning 221.7 Simulator Data 241.8 Input and Output 291.8.1 Data Acquisition 291.8.2 Digital-to-Analogue Conversion 301.8.3 Analogue-to-Digital Conversion 311.8.4 Multiplexing 331.8.5 Encoders 331.8.6 Digital Input/Output 341.8.7 Signal Conditioning 351.8.8 Embedded Systems 361.8.9 USB Interfacing 40References 422 Software Methods in Simulation 452.1 The Laplace Transform 452.2 Transfer Functions 472.3 Discrete-event Systems 542.4 Data Fitting 582.4.1 Data Sources 582.4.2 Least-squares Method 602.4.3 Spline Methods 632.4.4 Extrapolation 702.4.5 Observations on Data Fitting 722.5 Numerical Methods 722.6 Numerical Stability and Accuracy 802.6.1 Numerical Stability 802.6.2 Numerical Accuracy 822.7 Timing Analysis 842.8 Simulation Packages 87References 923 Aircraft Equations of Motion 933.1 Atmospheric Model 933.1.1 The Atmosphere 933.1.2 Wind 963.1.3 Turbulence 963.1.4 Wind Shear 983.2 Axes 993.2.1 Body Axes 993.2.2 Stability Axes 1013.2.3 Local Frame 1013.2.4 Earth-centred Earth-fixed Frame 1043.2.5 Rotating Earth Frame 1043.3 Quaternions 1053.4 Aerodynamics 1083.4.1 Performance and Handling 1093.4.2 Coefficient of Lift 1103.4.3 Coefficient of Drag 1123.4.4 Coefficient of Side Force 1133.4.5 Pitching Moment Coefficients 1143.4.6 Rolling Moment Coefficients 1153.4.7 Yawing Moment Coefficients 1153.4.8 Mach Number 1163.4.9 Observations 1173.5 Equations of Motion 1183.5.1 Forces 1203.5.2 Moments 1223.5.3 Long-Range Navigation 1253.6 Propulsion 1263.6.1 Piston Engines 1273.6.2 Turbofans 1343.7 Landing Gear 137References 1444 Flight Control Systems 1474.1 Automatic Flight Control 1474.2 Development of Flight Control Laws 1484.2.1 The Case for Offline Development and Testing 1484.2.2 SimPlot 1504.2.3 Trimming 1524.3 PID Control 1544.4 Automatic Modes 1574.4.1 Turn Coordinator 1574.4.2 Yaw Damper 1584.4.3 Pitch Rate Controller 1604.4.4 Auto-throttle 1634.4.5 Vertical Speed Hold 1654.4.6 Altitude Hold 1654.4.7 Heading Hold 1664.4.8 Observations on Automatic Modes 1704.5 Airbus Control Laws 1704.5.1 Pitch Normal Law 1714.5.2 Roll Rate Law 1734.6 Tracking 1744.7 Auto-land 1774.8 Flight Director 1804.9 Flight Management Systems 1814.9.1 Flight Control Unit 1824.9.2 Flight Management Systems Simulation 182References 1875 Navigation Systems 1895.1 The Earth 1895.1.1 Gravity 1895.1.2 Magnetic Variation 1905.2 Sensor Modelling 1915.3 Navigation Principles 1925.3.1 Position 1925.3.2 Airspeed 1945.3.3 Altitude 1955.3.4 Heading 1955.3.5 Distance and Bearing 1975.4 Navigation Databases 1995.5 Map Projections and Charts 2035.6 Navigation Computations 2075.7 Radio Navigation Aids 2125.7.1 Automatic Direction Finding (ADF) 2125.7.2 VHF Omni-directional Range 2145.7.3 Distance Measuring Equipment 2175.7.4 Instrument Landing System 2185.8 Traffic Collision Avoidance Systems 2215.9 Inertial Navigation Systems 2235.10 Satellite Navigation 230References 2416 Aircraft Displays 2436.1 OpenGL 2436.1.1 The Development of OpenGL 2436.1.2 Legacy OpenGL 2446.1.3 OpenGL Version 4 2456.2 glib – A 2D Graphics Library for Flight Simulation 2536.2.1 GPU Software Interface 2546.2.2 Dots, Vectors and Triangles 2566.2.3 Textures 2606.2.4 Fonts 2646.2.5 Matrix Transformations 2736.2.6 Summary of glib Functions 2756.3 Graphics Libraries 2756.3.1 GLFW 2776.3.2 cglm 2786.3.3 PngLib 2786.3.4 FreeImage 2796.3.5 FreeType 2816.3.6 Compiling, Linking and Loading Shader Programs 2816.3.7 Svg 2816.4 Design Considerations 2846.4.1 Absolute and Relative Rendering 2846.4.2 Memory Organisation 2866.5 EFIS Displays 2876.5.1 Primary Flight Display 2886.5.2 Navigation Flight Display 2926.5.3 EICAS Display 2946.6 Flight Instruments 2966.7 Soft Panels 303References 3087 Image Generation Systems 3097.1 IG Pipeline 3097.2 Visual Databases 3117.2.1 Constructing Visual Databases 3117.2.2 Visual Database Standards 3137.2.3 Visual Database Editing Tools 3147.2.4 Representative Visual Databases 3167.2.5 Visual Database Organisation 3197.2.6 Binary-spaced Partition Trees 3227.3 OpenSceneGraph 3237.4 X-Plane 11 3297.4.1 X-Plane 11 API 3297.4.2 An X-Plane 11 Plug-in 3307.4.3 OSG versus X-Plane 11 3337.5 Head-up Displays 3357.6 Digital Terrain Elevation Data 3377.7 Visualisation 3437.8 Observations 343References 3458 Sound Generation 3478.1 Sound Waveforms 3478.2 Sound Generation Methods 3508.2.1 WAV Format 3518.2.2 Fast Fourier Transform 3528.2.3 FFTW 3548.2.4 Filters 3568.3 OpenAL 3598.3.1 OpenAL Application Programming Interface 3598.3.2 Loading Sound Files 3608.3.3 Dynamic Sounds 3638.4 Tones 3648.4.1 Outer Marker 3658.4.2 Middle Marker 3678.4.3 Morse Code 3678.4.4 Warnings 3688.4.5 Background Sounds 3698.4.6 Turbofan Sounds 3698.4.7 Real-time Sound Generation 3718.5 Recordings 3728.5.1 Airspeed-related Sound 3728.5.2 Turbofan Engines 3738.6 Observations 373References 3749 The Instructor Station 3759.1 Requirements 3759.1.1 User Interfaces 3759.1.2 Instructor Station Requirements 3779.2 GUIs 3809.2.1 User Inputs 3809.2.2 Colour 3819.2.3 Prototyping 3819.2.4 User Actions 3849.2.5 Software Considerations 3849.3 Design of the User Interface 3879.3.1 Classification of Operations 3879.3.2 Design and Implementation of Menus 3909.3.3 Widgets 3959.3.4 Mouse Events 4009.4 Real-time Operation 4029.5 Charts and Maps 4059.6 Flight Data Recording 4089.6.1 Data Recording 4099.6.2 Data Display 4119.7 Scripting 4119.7.1 A Simple Scripting Language 4139.7.2 A Stack Machine 414References 42110 Validation 42310.1 Software Verification 42310.2 Static Validation 42410.2.1 I/O Systems 42510.2.2 Control Loading Systems 42610.2.3 Weather Module 42710.2.4 Navigation Systems 42810.2.5 Display Modules 42810.2.6 Visual Systems 43010.2.7 The Instructor Station 43210.2.8 Networking 43310.3 Aircraft Performance 43510.3.1 Taxiing 43610.3.2 Take-off 43610.3.3 Level Flight 43610.3.4 Climbing Flight 44010.3.5 Approach and Touchdown 44010.3.6 Turning Flight 44210.3.7 Sideslip 44410.3.8 Observations 44510.4 Dynamic Response 44510.4.1 Longitudinal Dynamics 44510.4.2 Lateral Dynamics 44710.4.3 Engine Failure 44910.4.4 Observations 45010.5 Octave and MATLAB 45110.5.1 Longitudinal Model 45210.5.2 Lateral Model 45610.6 Simulator Qualification 45910.6.1 Aeroplane Flight Simulator Evaluation Handbook – Volume I 46110.6.2 Aeroplane Flight Simulator Evaluation Handbook – Volume II 462References 463Appendix 465A1 System-wide #include files 465A2 Libraries 466A3 Boeing 747-100 466A4 Cessna- 172 468A5 Supporting Files 469A6 SimPlot 470A7 Raspberry Pi 470A8 Diagnostics 471A9 MSYS2 471A10 Miscellaneous 472Index 473