Introduction to UAV Systems

Preface Aerospace Series List Acknowledgments List of Acronyms Part One Introduction 1. History and Overview 1.1. Overview 1.2. History 1.2.1. Early History 1.2.2. The Vietnam War 1.2.3. Resurgence 1.2.4. Joint Operations 1.2.5. Desert Storm 1.2.6. Bosnia 1.2.7. Afghanistan and Iraq 1.2.8. Long-Range Long-Endurance Operations 1.3. Overview of UAV Systems 1.3.1. Air Vehicle 1.3.2. Mission Planning and Control Station 1.3.3. Launch and Recovery Equipment 1.3.4. Payloads 1.3.5. Data Links 1.3.6. Ground Support Equipment 1.4. The Aquila 1.4.1. Aquila Mission and Requirements 1.4.2. Air Vehicle 1.4.3. Ground Control Station 1.4.4. Launch and Recovery 1.4.5. Payload 1.4.6. Other Equipment 1.4.7. Summary 1.5. Global Hawk 1.5.1. Mission Requirements and Development 1.5.2. Air Vehicle 1.5.3. Payloads 1.5.4. Communications System 1.5.5. Development Setbacks 1.5. Predator Family 1.5.1. Predator Development 1.5.2. Reaper 1.5.3. Features 1.6. Top UAV Manufacturers 1.7. Ethical Concerns of UAVs Questions 2 Classes and Missions of UAVs 2.1. Overview 2.2. Classes of UAV Systems 2.2.1. Classification Criteria 2.2.2. Classification by Range and Endurance 2.2.3. Classification by Missions 2.2.4. The Tier System 2.3. Examples of UAVs by Size Group 2.3.1. Micro UAVs 2.3.2. Mini UAVs 2.3.3. Very Small UAVs 2.3.4. Small UAVs 2.3.5. Medium UAVs 2.3.6. Large UAVs 2.4. Expendable UAVs Questions Part Two The Air Vehicle 3 Aerodynamics 3.1. Overview 3.2. Aerodynamic Forces 3.3. Mach Number 3.4. Airfoil 3.5. Pressure Distribution 3.6. Drag Polar 3.7. The Real Wing and Airplane 3.8. Induced Drag 3.9. Boundary Layer 3.10. Friction Drag 3.11. Total Air-Vehicle Drag 3.12. Flapping Wings 3.13. Aerodynamic Efficiency Questions 4 Performance 4.1. Overview 4.2. Cruising Flight 4.3. Range 4.3.1. Range for a Non-Electric-Engine Propeller-Driven Aircraft 4.3.2. Range for a Jet-Propelled Aircraft 4.4. Endurance 4.4.1. Endurance for a Non-Electric-Engine Propeller-Driven Aircraft 4.4.2. Endurance for a Jet-Propelled Aircraft 4.5. Climbing Flight 4.6. Gliding Flight 4.7. Launch 4.8. Recovery Questions 5 Flight Stability and Control 5.1. Overview 5.2. Trim 5.2.1. Longitudinal Trim 5.2.2. Directional Trim 5.2.3. Lateral Trim 5.2.4. Summary 5.3. Stability 5.3.1. Longitudinal Static Stability 5.3.2. Directional Static Stability 5.3.3. Lateral Static Stability 5.3.4. Dynamic Stability 5.4. Control 5.4.1. Aerodynamic Control 5.4.2. Pitch Control 5.4.3. Directional Control 5.4.4. Lateral Control Questions 6 Propulsion 6.1. Overview 6.2. Propulsion Systems Classification 6.3. Thrust Generation 6.4. Powered Lift 6.5. Sources of Power 6.5.1. Four-Cycle Engine 6.5.2. Two-Cycle Engine 6.5.3. Rotary Engine 6.5.4. Gas Turbine Engines 6.5.5. Electric Motors 6.6. Sources of Electric Energy 6.6.1. Batteries 6.6.2. Solar Cells 6.6.3. Fuel Cells 6.7. Power and Thrust 6.7.1. Relation between Power and Thrust 6.7.2. Propeller 6.7.3. Variations of Power and Thrust with Altitude Questions 7 Air Vehicle Structures 7.1. Overview 7.2. Structural Members 7.2.1. Skin 7.2.3. Fuselage Structural Members 7.2.3. Wing and Tail Structural Members 7.2.4. Other Structural Members 7.3. Basic Flight Loads 7.4. Dynamic Loads 7.5. Structural Materials 7.5.1. Overview 7.5.2. Aluminum 7.6. Composite Materials 7.6.1. Sandwich Construction 7.6.2. Skin or Reinforcing Materials 7.6.3 Resin Materials 7.6.4. Core Materials 7.7. Construction Techniques 7.8. Basic Structural Calculations 7.8.1. Normal and Shear Stress 7.8.2. Deflection 7.8.3. Bulking load 7.8.4. Factor of Safety 7.8.5. Structural Fatigue Questions Part Three Mission Planning and Control 8 Mission Planning and Control Station 8.1. Introduction 8.2. MPCS Subsystems 8.3. MPCS Physical Configuration 8.4. MPCS Interfaces 8.5. MPCS Architecture 8.5.1. Fundamentals 8.5.2. Local Area Networks 8.5.3. Levels of Communication 8.5.4. Bridges and Gateways 8.6. Elements of a LAN 8.6.1. Layout and Logical Structure (Topology) 8.6.2. Communications Medium 8.6.3. Network Transmission and Access 8.7. OSI Standard 8.7.1. Physical Layer 8.7.2. Data-Link Layer 8.7.3. Network Layer 8.7.4. Transport Layer 8.7.5. Session Layer 8.7.6. Presentation Layer 8.7.7. Application Layer 8.8. Mission Planning 8.9. Pilot-In-Command Questions 9 Control of Air Vehicle and Payload 9.1. Overview 9.2. Levels of Control 9.3. Remote Piloting the Air Vehicle 9.3.1. Remote Manual Piloting 9.3.2. Autopilot-Assisted Control 9.3.3. Complete Automation 9.3.4. Summary 9.4. Autopilot 9.4.1. Fundamental 9.4.2. Autopilot Categories 9.4.3. Inner and Outer Loops 9.4.4. Overall Modes of Operation 9.4.5. Control Process 9.4.6. Control Axes 9.4.7. Controller 9.4.8. Actuator 9.4.9. Open-Source Commercial Autopilots 9.5. Sensors Supporting the Autopilot 9.5.1. Altimeter 9.5.2. Airspeed Sensor 9.5.3. Attitude Sensors 9.5.4. GPS 9.5.5. Accelerometers 9.6. Navigation and Target Location 9.7. Controlling Payloads 9.7.1. Signal Relay Payloads 9.7.2. Atmospheric, Radiological, and Environmental Monitoring 9.7.3. Imaging and Pseudo-Imaging Payloads 9.8. Controlling the Mission 9.9. Autonomy Questions Part Four Payloads 10 Reconnaissance/Surveillance Payloads 10.1. Overview 10.2. Imaging Sensors 10.3. Target Detection, Recognition, and Identification 10.3.1. Sensor Resolution 10.3.2. Target Contrast 10.3.3. Transmission through the Atmosphere 10.3.4. Target Signature 10.3.5. Display Characteristics 10.3.6. Range Prediction Procedure 10.3.7. A few Considerations 10.3.8. Pitfalls 10.4. The Search Process 10.4.1. Types of Search 10.4.2. Field of View 10.4.3. Search Pattern 10.4.4. Search Time 10.5. Other Considerations 10.5.1. Location and Installation 10.5.2. Stabilization of the Line of Sight 10.5.3. Gyroscope and Gimbal 10.5.4. Gimbal-Gyro Configuration 10.5.5. Thermal Design 10.5.6. Environmental Conditions Affecting Stabilization 10.5.7. Boresight 10.5.8. Stabilization Design Questions 11 Weapon Payloads 11.1. Overview 11.2. History of Lethal Unmanned Aircraft 11.3. Mission Requirements for Armed Utility UAVs 11.4. Design Issues Related to Carriage and Delivery of Weapons 11.4.1. Payload Capacity 11.4.2. Structural Issues 11.4.3. Electrical Interfaces 11.4.4. Electromagnetic Interference 11.4.5. Launch Constraints for Legacy Weapons 11.4.6. Safe Separation 11.4.7. Data Links 11.4.8. Payload Location 11.5. Signature Reduction 11.5.1. Acoustical Signatures 11.5.2. Visual Signatures 11.5.3. Infrared Signatures 11.5.4. Radar Signatures 11.5.5. Emitted Signals 11.5.6. Active Susceptibility Reduction Measures 11.6. Autonomy for Weapon Payloads 11.6.1. Fundamental Concept 11.6.2. Rules of Engagement Questions 12 Other Payloads 12.1. Overview 12.2. Radar 12.2.1. General Radar Considerations 12.2.2. Synthetic Aperture Radar 12.3. Electronic Warfare 12.4. Chemical Detection 12.5. Nuclear Radiation Sensors 12.6. Meteorological and Environmental Sensors 12.7. Pseudo-Satellites 12.8. Robotic Arm 12.9. Package and Cargo 12.10. Urban Air Mobility Questions Part Five Data Links 13 Data-Link Functions and Attributes 13.1. Overview 13.2. Background 13.3. Data-Link Functions 13.4. Desirable Data-Link Attributes 13.4.1. Worldwide Availability 13.4.2. Resistance to Unintentional Interference 13.4.3. Low Probability of Intercept (LPI) 13.4.4. Security 13.4.5. Resistance to Deception 13.4.6. Anti-ARM 13.4.7. Anti-Jam 13.4.8. Digital Data Links 13.4.9. Signal Strength 13.5. System Interface Issues 13.5.1. Mechanical and Electrical 13.5.2. Data-Rate Restrictions 13.5.3. Control-Loop Delays 13.5.4. Interoperability, Interchangeability, and Commonality 13.6. Antennas 13.6.1. Omnidirectional Antenna 13.6.2. Parabolic Reflectors 13.6.3. Array/Directional Antennas 13.6.4. Lens Antennas 13.7. Data Link Frequency Questions 14 Data-Link Margin 14.1. Overview 14.2. Sources of Data-Link Margin 14.2.1. Transmitter Power 14.2.2. Antenna Gain 14.2.3. Processing Gain 14.3. Anti-Jam Margin 14.3.1. Definition of Anti-Jam Margin 14.3.2. Jammer Geometry 14.3.3. System Implications of AJ Capability 14.3.4. Anti-Jam Uplinks 14.4. Propagation 14.4.1. Obstruction of the Propagation Path 14.4.2. Atmospheric Absorption 14.4.3. Precipitation Losses 14.5. Data-Link Signal-to-Noise Budget Questions 15 Data-Rate Reduction 15.1. Overview 15.2. Compression Versus Truncation 15.3. Video Data 15.3.1. Gray Scale 15.3.2. Encoding of Gray Scale 15.3.3. Effects of Bandwidth Compression on Operator Performance 15.3.4. Frame Rate 15.3.5. Control Loop Mode 15.3.6. Forms of Truncation 15.3.7. Summary 15.4. Non-Video Data 15.5. Location of the Data-Rate Reduction Function Questions 16 Data-Link Tradeoffs 16.1. Overview 16.2 Basic Tradeoffs 16.3. Pitfalls of “Putting Off” Data-Link Issues 16.4. Future Technology Questions Part Six Launch and Recovery 17 Launch Systems 17.1. Overview 17.2. Conventional Takeoff XXX 17.3. Basic Considerations 17.4. Launch Methods for Fixed-Wing Air Vehicles 14.4.1. Overview 17.4.2. Rail Launchers 17.4.3. Pneumatic Launchers 17.4.4. Hydraulic-Pneumatic Launchers 17.4.5. Zero Length RATO Launch of UAVs 17.4.6. Tube Launch 17.5. Rocket Assisted Takeoff xxx 17.5.1. RATO Configuration 17.5.2. Ignition Systems 17.5.3. Expended RATO Separation 17.5.4. Other Launch Equipment 17.5.5. Energy (Impulse) Required 17.5.6. Propellant Weight Required 17.5.7. Thrust, Burning Time, and Acceleration 17.6. Vertical Takeoff Questions 18 Recovery Systems 18.1. Overview 18.2. Conventional Landing 18.3. Vertical Net Systems 18.4. Parachute Recovery 18.5. VTOL UAVs 18.6. Mid-Air Retrieval 18.7. Shipboard Recovery 18.8. Break-Apart Landing 18.9. Skid and Belly Landing 18.10. Suspended Cables Questions 19 Launch and Recovery Tradeoffs 19.1. UAV Launch Method Tradeoffs 19.2. Recovery Method Tradeoffs 19.3. Overall Conclusions Questions 20 Rotary-Wing UAVs and Quadcopters 20.1. Overview 20.2. Rotary-Wing Configurations 20.2.1. Single Rotor 20.2.2. Twin Co-axial Rotors 20.2.3. Twin Tandem Rotors 20.2.4. Multi-copter 20.3. Hybrid UAVs 20.3.1. Tilt Rotor 20.3.2. Tilt Wing 20.3.3. Thrust Vectoring 20.3.4. Fixed-Wing Quadcopter Combination 20.4. Quadcopters 20.4.1. Overview 20.4.2. Aerodynamics 20.4.3. Control Questions References