Introduction to UAV Systems E-Book

Paul G. Fahlstrom

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: Aerospace Series (PEP)
• Sprache: Englisch

Seitenzahl: 985

Veröffentlichungsjahr: 2022

Beschreibung

The latest edition of the leading resource on unmanned aerial vehicle systems

In the newly revised Fifth Edition of Introduction to UAV Systems, an expert team of aviators, engineers, and researchers delivers the fundamentals of UAV systems for both professionals and students in UAV courses. Suitable for students in both Aerospace Engineering programs, as well as Flight and Aeronautics programs, this new edition now includes end-of-chapter questions and online instructor ancillaries that make it an ideal textbook.

As the perfect complement to the author's Design of Unmanned Aerial Systems, this book includes the history, classes, and missions of UAVs. It covers fundamental topics, like aerodynamics, stability and control, propulsion, loads and structures, mission planning, payloads, and communication systems. Brand-new materials in areas including autopilots, quadcopters, payloads, and ground control stations highlight the latest industry technologies.

The authors also discuss:

• A thorough introduction to the history of unmanned aerial vehicles, including their use in various conflicts, an overview of critical UAV systems, and the Predator/Reaper
• A comprehensive exploration of the classes and missions of UAVs, including several examples of UAV systems, like Mini UAVs, UCAVs, and quadcopters
• Practical discussions of air vehicles, including coverage of topics like aerodynamics, flight performance, stability, and control
• In-depth examinations of propulsion, loads, structures, mission planning, control systems, and autonomy

Perfect for professional aeronautical and aerospace engineers, as well as students and instructors in courses like Unmanned Aircraft Systems Design and Introduction to Unmanned Aerial Systems, Introduction to UAV Systems is also an indispensable resource for anyone. seeking coverage of the latest industry advances and technologies in UAV and UAS technology.

Leseprobe

Table of Contents

Cover

Series Page

Title Page

Copyright Page

Dedication Page

Preface

Series Preface

Acknowledgments

List of Acronyms

About the Companion Website

Part I: Introduction

1 History and Overview

1.1 Overview

1.2 History

1.3 Overview of UAV Systems

1.4 The Aquila

1.5 Global Hawk

1.6 Predator Family

1.7 Top UAV Manufacturers

1.8 Ethical Concerns of UAVs

Questions

2 Classes and Missions of UAVs

2.1 Overview

2.2 Classes of UAV Systems

2.3 Examples of UAVs by Size Group

2.4 Expendable UAVs

Questions

Part II: 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

4.4 Endurance

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

5.3 Stability

5.4 Control

6 Propulsion

6.1 Overview

6.2 Propulsion Systems Classification

6.3 Thrust Generation

6.4 Powered Lift

6.5 Sources of Power

6.6 Sources of Electric Energy

6.7 Power and Thrust

Questions

7 Air Vehicle Structures

7.1 Overview

7.2 Structural Members

7.3 Basic Flight Loads

7.4 Dynamic Loads

7.5 Structural Materials

7.6 Composite Materials

7.7 Construction Techniques

7.8 Basic Structural Calculations

Questions

Part III: 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

8.6 Elements of a LAN

8.7 OSI Standard

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

9.4 Autopilot

9.5 Sensors Supporting the Autopilot

9.6 Navigation and Target Location

9.7 Controlling Payloads

9.8 Controlling the Mission

9.9 Autonomy

Questions

Part IV: Payloads

10 Reconnaissance/Surveillance Payloads

10.1 Overview

10.2 Imaging Sensors

10.3 Target Detection, Recognition, and Identification

10.4 The Search Process

10.5 Other Considerations

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

11.5 Signature Reduction

11.6 Autonomy for Weapon Payloads

Questions

12 Other Payloads

12.1 Overview

12.2 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 V: 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

13.5 System Interface Issues

13.6 Antennas

13.7 Data Link Frequency

Questions

14 Data‐Link Margin

14.1 Overview

14.2 Sources of Data‐Link Margin

14.3 Anti‐Jam Margin

14.4 Propagation

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

15.4 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

Questions

Part VI: Launch and Recovery

17 Launch Systems

17.1 Overview

17.2 Conventional Takeoff

17.3 Basic Considerations

17.4 Launch Methods for Fixed‐Wing Air Vehicles

17.5 Rocket‐Assisted 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

20.3 Hybrid UAVs

20.4 Quadcopters

Questions

References

Index

End User License Agreement

List of Tables

Chapter 1

Table 1.1 RQ‐4B Global Hawk data and performance

Table 1.2 Reaper data and performance

Chapter 2

Table 2.1 Criteria for classification of UAVs

Table 2.2 US Air Force tiers

Table 2.3

Marine Corps tiers

Table 2.4 Army tiers

Chapter 3

Table 3.1 Typical Reynolds numbers

Chapter 6

Table 6.1 Energy density of some rechargeable batteries

Chapter 7

Table 7.1 Reinforcing (skin) materials for sandwich construction

Table 7.2 Resin materials

Table 7.3 Foam materials

Chapter 8

Table 8.1 Functions of an MPCS

Table 8.2 Functions of an MPCS

Chapter 9

Table 9.1 Intellectual levels of autonomous flight

Table 9.2 Control elements in three control planes

Chapter 10

Table 10.1 Lines or Cycles versus Range

Table 10.2 Single‐frame display search time

Chapter 11

Table 11.1 Weapon payloads

Chapter 13

Table 13.1 Commonly used frequency bands in communications and data links

Chapter 14

Table 14.1 Summary of calculations for Example 14.3

Table 14.2 Summary of calculations for Example 14.4

Table 14.3 Format for a data‐link budget

Table 14.4 Completed data‐link budget

Chapter 15

Table 15.1 Encoding of gray scale

Table 15.2 Recommended data rate reduction techniques for UAV video data

Chapter 16

Table 16.1 Hierarchy of data‐link attributes during design tradeoff

Chapter 19

Table 19.1 Wheeled takeoff using a runway

Table 19.2

Wheeled takeoff using prepared takeoff areas (truck launch)

Table 19.3

Pneumatic rail launchers – split‐tube type

Table 19.4

Pneumatic rail launchers – air motor type

Table 19.5

Hydraulic‐pneumatic rail launchers

Table 19.6

RATO launchers

Tables 19.7 Vertical takeoff (VTOL AV)

Table 19.8

Wheel landings using a runway

Table 19.9

Skid and belly landings (prepared landing sites)

Table 19.10

Vertical‐net systems

Table 19.11

Parachute recovery

Table 19.12

Parafoil recovery

Table 19.13

VTOL – vertical landing

Table 19.14

Mid‐air retrieval

Tables 19.15

Break‐apart landing

Table 19.16

Suspended cables

Chapter 20

Table 20.1 General characteristics of a quadcopter

List of Illustrations

Chapter 1

Figure 1.1 Generic UAV system

Figure 1.2 Mission planning and control station for a long‐range UAV

Figure 1.3 Aquila air vehicle

Figure 1.4 Global Hawk

Figure 1.5 General Atomics MQ‐9 ReaperLeft: A British MQ‐9A Reaper operati...

Chapter 2

Figure 2.1 The Kratos XQ‐58 Valkyrie

Figure 2.2 Very small UAVs

Figure 2.3 Small UAVs

Figure 2.4 Boeing‐Insitu ScanEagle

Figure 2.5 Medium UAVs

Figure 2.6 Large UAVs

Figure 2.7 Switchblade UAV

Chapter 3

Figure 3.1 Forces on an air vehicle during a level flight

Figure 3.2 Aerodynamic lift, drag, and pitching moment

Figure 3.3 Airfoil geometric parameters

Figure 3.4 Infinite span wing

Figure 3.5 NACA 23021 airfoil profile

Figure 3.6 NACA 23021 airfoil coefficients versus angle of attack

Figure 3.7 NACA 23021 airfoil coefficients versus lift coefficient

Figure 3.8 Pressure distribution for an airfoil section

Figure 3.9 Northrop Grumman X‐47B UCAV

Figure 3.10 Net pressure distribution over an airfoil

Figure 3.11 Spanwise pressure distribution around a 3d wing

Figure 3.12 Downwash

Figure 3.13 Airplane drag polar

Figure 3.14 Elliptical lift distribution

Figure 3.15 Induced drag diagram

Figure 3.16 Typical boundary layer over a flat surface

Figure 3.17 Typical boundary layer over a wing/tail airfoil

Figure 3.18 Boundary layer velocity profile inside a convergent–divergent du...

Figure 3.19 Skin friction versus Reynolds number

Figure 3.20 Wing flapping diagram

Figure 3.21 Flight of a bird

Figure 3.22 Wing articulation

Chapter 4

Figure 4.1 Main phases in a typical flight mission

Figure 4.2 Forces on an air vehicle in a level flight

Figure 4.3 Range versus weight ratio for propeller‐driven aircraft

Figure 4.4 Endurance versus weight ratio for propeller‐driven aircraft

Figure 4.5 Force diagram in a climbing flight

Figure 4.6 Power versus velocity

Figure 4.7 Power versus velocity for several altitudes

Figure 4.8 Launch forces and parameters during a launch

Figure 4.9 Recovery of a UAV using a vertical net

Chapter 5

Figure 5.1 A typical flight envelope

Figure 5.2 Forces and moments in a fixed‐wing UAV in the

xz

plane

Figure 5.3 Longitudinal moment balance diagram

Figure 5.4 Pitching moment coefficient versus lift coefficient

Figure 5.5 Contributors to pitching moment

Figure 5.6 Directional stability (top view)

Figure 5.7 Directional stability

Figure 5.8 Lateral stability (front view)

Figure 5.9 Control surfaces of a fixed‐wing UAV

Figure 5.10 Longitudinal control via elevator deflection

Figure 5.11 Pitching moment coefficient versus elevator deflection – revised...

Figure 5.12 Directional control via rudder deflection (top view)

Figure 5.13 Aileron deflection to create a roll (front view)

Chapter 6

Figure 6.1 Classification of air vehicle engines

Figure 6.2 Momentum generator

Figure 6.3 Actuator disk

Figure 6.4 Disk loading versus power loading

Figure 6.5 Lift‐to‐power ratio versus exit velocity

Figure 6.6 Engine cycles

Figure 6.7 Two‐cycle process

Figure 6.8 Torque variation

Figure 6.9 Rotary engine

Figure 6.10 Gas turbine engine schematic

Figure 6.11 Turbofan (left) and turboprop (right) engines

Figure 6.12 NASA and AeroVironment’s Helios with solar‐powered engines

Figure 6.13 PIN junction

Figure 6.14 Fuel cell

Figure 6.15 Propeller efficiency and engine thrust

Figure 6.16 Propeller normal and tangential velocities

Figure 6.17 Typical variations for fixed‐pitch prop efficiencies

Figure 6.18 Typical variations for engine thrust and power versus altitude

Chapter 7

Figure 7.1 Primary structural members of a wing/fuselage for a fixed‐wing ai...

Figure 7.2 Inspection door and cutout in Fuselage of RQ‐4 Global Hawk

Figure 7.3 Aerodynamic forces and moments on an aircraft during flight

Figure 7.4 Wing lift distribution

Figure 7.5 Bending stress

Figure 7.6 Uniformly loaded wing

Figure 7.7 Shear force and bending moment diagram

Figure 7.8 Forces during roll

Figure 7.9 Maneuver load diagram

Figure 7.10 Gust diagram

Figure 7.11 Sandwich panel

Figure 7.12 Common cross‐sections of spars

Figure 7.13 Beam under normal and shear stresses

Figure 7.14 Bending moment at the wing root

Figure 7.15 Global Hawk wing tip deflection (Source: Tom Miller / NASA)

Figure 7.16 Deflection of a cantilever beam under a uniform distributed load...

Chapter 8

Figure 8.1 MPCS block diagram

Figure 8.2 A radio‐controlled model aircraft with its controller

Figure 8.3 Worthington Sharpe portable GCS (Source: Samworthington / Wikimed...

Figure 8.4 MQ‐1 Predator Operator's workstation (Source: General Atomics Aer...

Figure 8.5 Ground station setup for a MALE UAV

Chapter 9

Figure 9.1 Remote piloting of the aircraft

Figure 9.2 Block diagram of a generic closed‐loop remote flight control syst...

Figure 9.3 Signals in a remotely closed‐loop flight control system

Figure 9.4 Control, guidance, and navigation systems in an autopilot

Figure 9.5 Block diagram of the closed‐loop control system

Figure 9.6 Flight control system block diagram for a fixed‐wing UAV

Figure 9.7 Geometry of target position determination

Figure 9.8 Block diagram of a remote generic closed‐loop payload control sys...

Chapter 10

Figure 10.1 Reconnaissance/surveillance payloads general classification

Figure 10.2 Two small reconnaissance sensors

Figure 10.3 Target with resolution “lines” superimposed

Figure 10.4 Johnson Criteria for the probability of success

Figure 10.5 Angle subtended by the smallest object for an imaging sensor

Figure 10.6 Generic MRC curve

Figure 10.7 Generic MRT curve

Figure 10.8 Extinction coefficient versus visibility

Figure 10.9 Load‐line analysis

Figure 10.10 NASA Viking 400

Figure 10.11 Geometry for a typical UAV field of view on the ground

Figure 10.12 Automated search pattern

Figure 10.13 Gyroscope and gimbal

Figure 10.14 Two‐ and three‐gimbal configurations

Chapter 11

Figure 11.1 Armed Predator, showing missiles on launch rails and optical dom...

Figure 11.2 Rotary launcher retracted and extended

Figure 11.3 Fall off in perceived sound level as altitude of an overflight i...

Figure 11.4 Electromagnetic spectrum

Figure 11.5 Concept of a radar cross‐section

Figure 11.6 90‐degree dihedral and trihedral geometries

Chapter 12

Figure 12.1 Emitted and reflected signals

Figure 12.2 NASA Global Hawk

Figure 12.3 NASA Pathfinder

Figure 12.4 Amazon Prime Air UAV (Source: Amazon, Inc.)

Chapter 13

Figure 13.1 Elements of a UAS data link

Figure 13.2 Jamming via sending noise to a data link signal

Figure 13.3 Parabolic reflector antenna for a transmitter or receiver

Figure 13.4 Yagi‐Uda antenna

Figure 13.5 Lunberg lens antenna

Figure 13.6 Zoned lens antenna

Chapter 14

Figure 14.1 Definition of beam width – top or side view

Figure 14.2 Geometry for antenna gain

Figure 14.3 Antenna height and Earth radius

Figure 14.4 Line‐of‐sight range versus altitude

Figure 14.5 Direct spread‐spectrum processing gain

Figure 14.6 Schematic of a frequency‐hopping waveform

Figure 14.7 Scrambling, redundancy, and addition of error‐detection

Figure 14.8 Uplink jamming for omnidirectional receive antenna

Figure 14.9 Downlink jammer geometry

Figure 14.10 Geometry for a downlink with a high‐gain antenna

Figure 14.11 Jamming geometry for up‐ and downlinks for multiple jammers

Figure 14.12 Transmitted bandwidth versus processing gain for several data r...

Figure 14.13 Fresnel zones of an electromagnetic beam

Chapter 15

Figure 15.1 Effect of compression on probability of detecting targets

Figure 15.2 Effect of data compression on recognition of targets

Figure 15.3 Effect of frame rate on time to complete a fine‐slewing task

Figure 15.4 Effect of frame rate on probability of success for a manual sear...

Chapter 17

Figure 17.1 Velocity versus stroke

Figure 17.2 Kinetic energy versus mass

Figure 17.3 Force versus stroke for various vehicle weights

Figure 17.4 Force versus stroke for an elastic cord

Figure 17.5 Force versus stroke for a pneumatic‐hydraulic launcher

Figure 17.6 Truck launch

Figure 17.7 Boeing Insitu RQ‐21 Blackjack (Source: Lance Cpl. Rhita Daniel /...

Figure 17.8 HP 2002 launcher

Figure 17.9 Energy requirements for a zero‐length launcher

Chapter 18

Figure 18.1 Pioneer installation on USS Iowa (Reproduced by permission of En...

Figure 18.2 Cross parachute (Reproduced by permission of Engineering Arresti...

Figure 18.3 Parafoil recovery

Figure 18.4 Parafoil recovery with winch

Figure 18.5 VTOL recovery by tether

Figure 18.6 VTOL recovery by automatic landing

Figure 18.7 Launch and recovery platform

Figure 18.8 Mid‐air retrieval

Figure 18.9 Mid‐air recovery sequence – snagging

Figure 18.10 Mid‐air recovery sequence – recovery

Figure 18.11 AeroVironment RQ‐11 Raven

Figure 18.12 Recovery of an RQ‐21A Integrator at sea with a suspended cable...

Chapter 19

Figure 19.1 Cost tradeoffs for rail versus RATO launch

Chapter 20

Figure 20.1 Rotary‐wing configurations

Figure 20.2 NASA and AeroVironment Ingenuity unmanned helicopter

Figure 20.3 UAV Factory Penguin C Mk2 VTOL UAV

Figure 20.4 Quadcopter configuration

Figure 20.5 Propeller and rotary wing (top view)

Figure 20.6 Lift and thrust forces (side view)

Guide

Cover Page

Series Page

Title Page

Copyright Page

Dedication Page

Preface

Series Preface

Acknowledgments

List of Acronyms

About the Companion Website

Table of Contents

Begin Reading

Introduction To Uav Systems

Index

WILEY END USER LICENSE AGREEMENT

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Aerospace Series List

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Sustainable Aviation Technology and Operations: Research and Innovation Perspectives

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Foundations of Space Dynamics

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2020

Essentials of Supersonic Commercial Aircraft Conceptual Design

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Design of Unmanned Aerial Systems

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Future Propulsion Systems and Energy Sources in Sustainable Aviation

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Introduction to Flight Testing

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Flight Dynamics and Control of Aero and Space Vehicles

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Theory of Lift: Introductory Computational Aerodynamics with MATLAB®/Octave

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August 2012

Sense and Avoid in UAS: Research and Applications

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April 2012

Morphing Aerospace Vehicles and Structures

Valasek

April 2012

Gas Turbine Propulsion Systems

MacIsaac and Langton

July 2011

Basic Helicopter Aerodynamics, Third Edition

Seddon and Newman

July 2011

Advanced Control of Aircraft, Spacecraft, and Rockets

Tewari

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Cooperative Path Planning of Unmanned Aerial Vehicles

Tsourdos et al.

November 2010

Principles of Flight for Pilots

Swatton

October 2010

Air Travel and Health: A Systems Perspective

Seabridge et al.

September 2010

Design and Analysis of Composite Structures: With Applications to Aerospace Structures

Kassapoglou

September 2010

Unmanned Aircraft Systems: UAVS Design, Development, and Deployment

Austin

April 2010

Introduction to Antenna Placement and Installations

Macnamara

April 2010

Principles of Flight Simulation

Allerton

October 2009

Aircraft Fuel Systems

Langton et al.

May 2009

The Global Airline Industry

Belobaba

April 2009

Computational Modelling and Simulation of Aircraft and the Environment: Volume 1 – Platform Kinematics and Synthetic Environment

Diston

April 2009

Handbook of Space Technology

Ley, Wittmann, and Hallmann

April 2009

Aircraft Performance Theory and Practice for Pilots

Swatton

August 2008

Surrogate Modelling in Engineering Design: A Practical Guide

Forrester, Sobester, and Keane

August 2008

Aircraft Systems, Third Edition

Moir and Seabridge

March 2008

Introduction to Aircraft Aeroelasticity and Loads

Wright and Cooper

December 2007

Stability and Control of Aircraft Systems

Langton

September 2006

Military Avionics Systems

Moir and Seabridge

February 2006

Design and Development of Aircraft Systems

Moir and Seabridge

June 2004

Aircraft Loading and Structural Layout

Howe

May 2004

Aircraft Display Systems

Jukes

December 2003

Civil Avionics Systems

Moir and Seabridge

December 2002

Introduction to UAV Systems

Paul Gerin Fahlstrom

UAV Manager, US Army Material Command

Thomas James Gleason

Gleason Research Associates, Inc.

Mohammad H. Sadraey

Southern New Hampshire University

Fifth Edition

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Names: Fahlstrom, Paul Gerin, author. | Gleason, Thomas J., author. | Sadraey, Mohammad H., author.Title: Introduction to UAV systems / Paul Gerin Fahlstrom, Thomas James Gleason, Mohammad H. Sadraey.Description: Fifth edition. | Hoboken, NJ : Wiley, 2022. | Series: Aerospace series | Includes bibliographical references and index.Identifiers: LCCN 2022001629 (print) | LCCN 2022001630 (ebook) | ISBN 9781119802617 (cloth) | ISBN 9781119802631 (adobe pdf) | ISBN 9781119802624 (epub)Subjects: LCSH: Drone aircraft. | Cruise missiles.Classification: LCC UG1242.D7 F34 2022 (print) | LCC UG1242.D7 (ebook) | DDC 623.74/69–dc23/eng/20220202LC record available at https://lccn.loc.gov/2022001629LC ebook record available at https://lccn.loc.gov/2022001630

Cover Design: WileyCover Image: © MQ‐9 Reaper unmanned aerial vehicle, public domain, Wikimedia Commons

This book is dedicated to our wives, Beverly Ann Evans Fahlstrom, Archodessia Glyphis Gleason, and Seyedeh Zafarani, who have provided support and encouragement throughout the process of its preparation.

Preface

Introduction to UAV Systems, Fifth Edition, has been written to meet the needs of both newcomers to the world of unmanned aerial vehicle (UAV) systems and experienced members of the UAV community who desire an overview and who, though they may find the treatment of their particular discipline elementary, will gain valuable insights into the other disciplines that contribute to a UAV system. The material has been presented such that it is readily understandable to college freshman and to both technical and nontechnical persons working in the UAV field, and is based on standard engineering texts as well as material developed by the authors while working in the field. Most equations have been given without proof and the reader is encouraged to refer to standard texts of each discipline when engaging in actual design or analysis as no attempt is made to make this book a complete design handbook.

This book is also not intended to be the primary text for an introductory course in aerodynamics or imaging sensors or data links. Rather, it is intended to provide enough information in each of those areas, and others, to illustrate how they all play together to support the design of complete UAV systems and to allow the reader to understand how the technology in all of these areas affect the system‐level tradeoffs that shape the overall system design. As such, it might be used as a supplementary text for a course in any of the specialty areas to provide a system‐level context for the specialized material.

For a beginning student, we hope that it will whet the appetite for knowing more about at least one of the technology areas and demonstrate the power of even the simplest mathematical treatment of these subjects in allowing understanding of the tradeoffs that must occur during the system design process.

For a UAV user or operator, we hope that it will provide understanding of how the system technology affects the manner in which the UAV accomplishes its objectives and the techniques that the operator must use to make that happen.

For a “subject matter expert” in any of the disciplines involved in the design of a UAV system, we hope that it will allow better understanding of the context in which his or her specialty must operate to produce success for the system as a whole and why other specialists may seem preoccupied with things that seem unimportant to him or her.

Finally, for a technology manager, we hope that this book can help him or her understand how everything fits together, how important it is to consider the system‐integration issues early in the design process so that the integration issues are considered during the basic selection of subsystem designs, and help him or her understand what the specialists are talking about and, perhaps, ask the right questions at critical times in the development process.

Part One contains a brief history and overview of UAVs in Chapter 1 and a discussion of classes and missions of UAVs in Chapter 2.

Part Two is devoted to the design of the air vehicle including basic aerodynamics, performance, stability and control, propulsion and loads, structures and materials in Chapters 3 through 7.

Part Three discusses the mission planning, control function, and autopilot in Chapter 8 and operational control in Chapter 9.

Part Four has three chapters addressing payloads. Chapter 10 discusses the most universal types of payloads, reconnaissance, and surveillance sensors. Chapter 11 discusses weapons payloads, a class of payloads that has become prominent since its introduction about 10 years ago. Chapter 12 discusses a few of the many other types of payloads that may be used on UAVs.

Part Five covers data links, the communication subsystems used to connect the air vehicle to the ground controllers, and delivers the data gathered by the air‐vehicle payloads. Chapter 13 describes and discusses basic data‐link functions and attributes. Chapter 14 covers the factors that affect the performance of a data link, including the effects or intentional and unintentional interference. Chapter 15 addresses the impact on the operator and system performance of various approaches to reducing the data‐rate requirements of the data link to accommodate limitations on available bandwidth. Chapter 16 summarizes data‐link tradeoffs, which are one of the key elements in the overall system tradeoffs.

Part Six describes approaches for the launch and recovery of UAVs, including ordinary takeoff and landing, but extending to many approaches not used for manned aircraft. Chapter 17 describes launch systems and Chapter 18 recovery systems. Chapter 19 summarizes the tradeoffs between the many different launch and recovery approaches. Chapter 20 – a new chapter in this edition – is dedicated to fundamentals, control, and characteristics of rotary‐wing UAVs and quadcopters.

Introduction to UAV Systems was first published in 1992. Much has happened in the UAV world in the 30 years since the first edition was written. In the Preface to the second edition (1998), we commented that there had been further problems in the development process for tactical UAVs but that there had been some positive signs in the use of UAVs in support of the Bosnian peace‐keeping missions and that there even was some talk of the possible use of “uninhabited” combat vehicles within the US Air Force that was beginning for the first time to show some interest in UAVs. At that time, we concluded that “despite some interest, and real progress in some areas, however, we believe that the entire field continues to struggle for acceptance, and UAVs have not come of age and taken their place as proven and established tools.”

In the 30 years since we made that statement, the situation has changed dramatically. UAVs have been widely adopted in the military world, unmanned combat vehicles have been deployed and used in highly visible ways, often featured on the evening news, and unmanned systems now appear to be serious contenders for the next generation of fighters and bombers.

While civilian applications still lag, impeded by the very‐real issues related to mixing manned and unmanned aircraft in the general airspace, the success of military applications has encouraged attempts to resolve these issues and establish unmanned aircraft in nonmilitary roles.

The Fifth Edition has been extensively revised and restructured. The revisions have, we hope, made some of the material clearer and easier to understand and have added a number of new subjects in areas that have become more prominent in the UAV world during the last two decades, such as quadcopter, automatic flight control systems, new payloads, and the various levels of autonomy that may be given to an air vehicle. It also revises a number of details that have clearly been overtaken by events, and all chapters have been brought up to date to introduce some of the new terminology, concepts, and specific UAV systems that have appeared over the last 12 years. However, the basic subsystems that make up a UAV “system of systems” have not greatly changed, and at the level that this text addresses them, the basic issues and design principles have not changed since the first edition was published.

The first two authors – sadly, now deceased ‐ met while participating in a “red team” that was attempting to diagnose and solve serious problems in an early UAV program. The eventual diagnosis was that there had been far too little “systems engineering” during the design process and that various subsystems did not work together as required for system‐level success. This book grew out of a desire to write down at least some of the “lessons learned” during that experience and make them available to those who design UAV systems in the future.

Supplementary materials, including answers to end‐of‐chapter questions, are available for registered instructors who adopt this book as a course text. Please visit www.wiley.com/go/fahlstrom/uavsystems5e for information and to register for access to these resources.

We believe that most of those lessons learned are universal enough that they are just as applicable today as they were when they were learned years ago, and hope that this book can help future UAV system designers apply them and avoid having to learn them again the “hard way.”

Mohammad Hashem SadraeySeptember 2021

The Kettering Bug (Photograph courtesy of Norman C. “Dutch” Heilman)

Series Preface

This book is a welcome addition to the Aerospace Series, continuing the tradition of the Series in providing clear and practical advice to practitioners in the field of aerospace. This book will appeal to a wide readership and is an especially good introduction to the subject by extending the range of titles on the topic of unmanned air vehicles, and more importantly presenting a systems viewpoint of unmanned air systems. This is important as the range of vehicles currently available provides a diverse range of capabilities with differing structural designs, propulsions systems, payloads, ground systems, and launch/recovery mechanisms. It is difficult to see any rationalization or standardization of vehicles or support environment in the range of available solutions.

The book covers the history of unmanned flight and describes the range of solutions available world‐wide. It then addresses the key aspects of the subsystems such as structure, propulsion, navigation, sensor payloads, launch and recovery, and associated ground systems in a readable and precise manner, pulling them together as elements of a total integrated system. In this way it is complementary to other systems books in the Series.

It is important for engineers and designers to visualize the totality of a system in order to gain an understanding of all that is involved in designing new vehicles or in writing new requirements to arrive at a coherent design of vehicle and infrastructure. Even more important if the new vehicle needs to interact and inter‐operate with other vehicles or to operate from different facilities.

If unmanned air systems are going to become accepted in civilian airspace and in commercial applications then it is vital that a set of standards and design guidelines is in place to ensure consistency, to aid the certification process, and to provide a global infrastructure similar to that existing for today’s manned fleets. Without that understanding, certification of unmanned air vehicles to operate in civilian controlled airspace is going to be a long and arduous task.

This book sets the standard for a definitive work on the subject of unmanned air systems by providing a measure of consistency and a clear understanding of the topic.

Acknowledgments

We would like to thank Engineering Arresting System Corporation (ESCO) (Aston, PA), Division of Zodiac Aerospace and General Atomics Aeronautical Systems, Inc., for providing pictures and diagrams and/or other information relating to their air vehicles and equipment.

The Joint UAV Program Office (Patuxent River Naval Air Station, MD) and the US Army Aviation and Missile Command (Huntsville, AL) both provided general information during the preparation of the first edition.

We especially thank Mr. Robert Veazey, who provided the original drafts of the material on launch and recovery while an employee of ESCO, and Mr. Tom Murley, formerly of Lear Astronics, and Mr. Bob Sherman for their critical reading of the draft and constructive suggestions.

Great appreciation goes to Mrs. Lauren Poplawski, Acquisitions Editor for Mechanical and Aerospace Engineering at Wiley, who suggested the third author to prepare the Fifth Edition, and provided him with guidance through the preparation of the manuscript. We are also thankful for Kimberly Monroe‐Hill, Managing Editor and Gabby Robles, Associate Managing Editor, who provided some helpful information when the manuscript for this new edition was sculpted. The authors are also very grateful to Copy Editor Mrs. Patricia Bateson for her careful reading of the manuscript for the Fifth Edition and for many helpful suggestions related to style and grammar. People at Wiley were very patient with us throughout the process of working out the details of how that might be accomplished.

List of Acronyms

AC

alternating current, aerodynamic center

ADC

analog‐to‐digital converter

ADT

air data terminal

AFCS

automatic flight control systems

AGL

above ground level

Ah

ampere‐hours

AI

artificial intelligence

AJ

anti jam

AOA

angle of attack

AR

aspect ratio

ARM

antiradiation munition

AV

air vehicle

BD

bi‐directional

BIT

built‐in test

BVLOS

beyond visual line of sight

BLOS

beyond line of sight

C2

command and control

CARS

common automatic recovery system

CBR

chemical, biological, radiological

CCD

charge‐coupled device

CFD

computational fluid dynamics

CG

center of gravity

CLRS

central launch and recovery section

CP

center of pressure

CPU

central processing unit

COMINT

communication intelligence

CW

continuous wave

DAA

detect and avoid

DAC

digital‐to‐analog converter

dB

decibel

dBA

dBs relative to the lowest pressure difference that is audible to a person

dBmv

dBs relative to 1 mV

dBsm

dB relative to 1 m

2

DC

direct current

DF

direction finding

DOF

degrees of freedom

ECCM

electronic counter‐countermeasures

ECM

electronic countermeasure

ELINT

electronic intelligence

EMI

electromagnetic interference

EO

electro optic

ERP

effective radiated power

ESM

electronic support measure

eVTOL

electric vertical take‐off and landing

EW

electronic warfare

FAA

Federal Aviation Administration

FAR

Federal Aviation Regulations

FCS

forward control section

FEM

finite element method

FLIR

forward‐looking infrared

FLOT

Forward Line of Own Troops

FOV

field of view

fps

frames per second

FPV

first‐person view

FSED

Full Scale Engineering Development

GCS

ground control station

GDT

ground data terminal

GHz

giga hertz

GNC

Guidance‐Navigation‐Control

GPS

global positioning system

GSE

ground support equipment

Gyro

gyroscope

HALE

high‐altitude, long endurance

HELLFIRE

helicopter launched fire and forget missile

HERO

Hazards of Electromagnetic Radiation to Ordnance

HMMWV

High Mobility Multipurpose Wheeled Vehicle

HP

hydraulic‐pneumatic

HTOL

horizontal takeoff and landing

IAI

Israeli Aircraft Industries

IC

integrated circuit

IFF

identification friend or foe

IMC

Image Motion Compensation

iOS

iPhone operating system

IR

infrared

ISR

Intelligence, Surveillance, Reconnaissance

ISO

International Organization for Standardization

JATO

Jet Assisted Take‐Off

JII

Joint Integration Interface

JPEG

Joint Photographic Experts Group

JPO

joint project office

JSTARS

Joint Surveillance Target Attack Radar System

KE

kinetic energy

LAN

local area network

Li‐ion

lithium ion

Li‐poly

lithium polymer

LOS

line of sight

LPI

low‐probability of intercept

LQR

linear quadratic regulator

mAh

milli ampere hour

MALE

medium‐altitude, long endurance

MARS

mid‐air recovery system

MART

Mini Avion de Reconnaissance Telepilot

Mbps

mega bits per second

MDO

multidisciplinary design optimization

MEMS

Micro‐Eectro‐Mechanical System

MET

meteorological

MICNS

Modular Integrated Communication and Navigation System

MPCS

mission planning and control station

MRC

minimum resolvable contrast

MRDT

minimum resolvable delta in temperature

MRT

minimum resolvable temperature

MSL

mean sea level

MTF

modulation transfer function

MTI

Moving Target Indicator

NACA

National Advisory Committee for Aeronautics

NAS

National Airspace System

NASA

National Aeronautics and Space Administration

NDI

non‐developmental item

NiCd

nickel cadmium

NiMH

nickel metal hydride

nm

nautical mile

NOAA

National Oceanic and Atmospheric Administration

NP

neutral point

OBC

optical bar camera

OSD

on‐screen display

OSI

Open System Interconnection

OT

operational test

PGM

precision guided munition

PIC

Pilot In Command

PID

Proportional, Integral, Derivative

PIN

positive intrinsic negative

PLSS

Precision Location and Strike System

QFT

quantitative feedback theory

RAM

radar‐absorbing material

RAP

radar‐absorbing paint

RATO

rocket‐assisted takeoff

RC Plane

radio‐controlled airplane, remotely controlled airplane

R&D

Research and Development

RCS

radar cross‐section

RF

radio frequency

RGT

remote ground terminal

RMS

root mean square

ROC

rate of climb

RPG

rocket propelled grenade

RPM

revolutions per minute

RPA

remotely piloted aircraft

RPV

remotely piloted vehicle

SAR

synthetic aperture radar

SEAD

Suppression of Enemy Air Defense

SF

safety factor

shp

shaft horsepower

SIGINT

signal intelligence

SLAR

side‐looking airborne radar

SOTAS

Stand‐Off Target Acquisition System

SPARS

Ship Pioneer Arresting System

sUAS

small unmanned aircraft systems

TADARS

Target Acquisition/Designation and Aerial Reconnaissance System

TUAV

tactical UAV

UAM

Urban Air Mobility

UAS

unmanned aerial system

UAV

unmanned aerial vehicle

UCAV

unmanned combat aerial vehicle

UD

unidirectional

VLOS

visual line‐of‐sight

VTOL

vertical takeoff and landing

About the Companion Website

This book is accompanied by a companion website:

https://www.wiley.com/go/fahlstrom/uavsystems5e

The website includes:

Solutions manual

Part IIntroduction

Part One provides a general background for an introduction to the technology of unmanned aerial vehicle systems, called “UAV systems” or “unmanned aerial systems” (UAS). This part is comprised of two chapters, 1 and 2.

Chapter 1 presents a brief history of UAVs. It then identifies and describes the functions of the major elements (subsystems) that may be present in a generic UAS. Finally, it provides a short history of a major UAV development program that failed to produce a fielded UAS, despite significant success in many of the individual subsystems, and teaches useful lessons about the importance of understanding the inter‐relationship and interactions of the subsystems of the UAS and the implications of system performance requirements at a total‐systems level. This story is told here to emphasize the importance of the word “system” in the terms “UAV System” and “UAS.”

Chapter 2 contains a survey of UAS that have been or presently are in use and discusses various schemes that are used to classify UAV systems according to their size, endurance, and/or mission. The information in this chapter is subject to becoming dated because the technology of many of the subsystems of a UAS is evolving rapidly as they become more and more part of the mainstream after many years of being on the fringes of the aeronautical engineering world. Nonetheless, some feeling for the wide variety of UAS concepts and types is needed to put the later discussion of design and system integration issues into context. Currently about 100 countries are employing military drones.

1History and Overview

1.1 Overview

The first portion of the chapter reviews the history of UAV systems from the earliest and crudest “flying objects” through the events of the last decade, which has been a momentous period for UAV systems.

The second portion of the chapter describes the subsystems that comprise a complete UAV system configuration to provide a framework for the subsequent treatment of the various individual technologies that contribute to a complete UAS. The air vehicle itself is a complicated system including structures, aerodynamic elements (wings and control surfaces), propulsion systems, and control systems. The complete system includes, in addition, sensors and other payloads, communication packages, and launch and recovery subsystems.

Finally, a cautionary tale is presented to illustrate why it is important to consider the UAV system as a whole rather than to concentrate only on individual components and subsystems. This is the story of a UAS that was developed between about 1975 and 1985 and that may be the most ambitious attempt at completeness, from a system standpoint, that has so far been undertaken in the UAS community.

It included every key UAS element in a totally self‐contained form, all designed from scratch to work together as a portable system that required no local infrastructure beyond a relatively small open field in which a catapult launcher and a net recovery system could be located. This system, called the Aquila remotely piloted vehicle (RPV) system, was developed and tested over a period of about a decade at a cost that approached a billion dollars. It eventually could meet most of its operational requirements.

The Aquila UAS turned out to be very expensive and required a large convoy of 5‐ton trucks for transportation. Most importantly, it did not fully meet some unrealistic expectations that had been built up over the decade during which it was being developed. It was never put in production or fielded. Nonetheless, it remains the only UAS of which the authors are aware that attempted to be complete unto itself and it is worth understanding what that ambition implied and how it drove costs and complexity in a way that eventually led the system to be abandoned in favor of less complete, self‐sufficient, and capable UAV systems that cost less and required less ground support equipment.

1.2 History

1.2.1 Early History

Throughout their history, UAV systems have tended to be driven by military applications, as is true of many areas of technology, with civilian applications tending to follow once the development and testing had been accomplished in the military arena.

One could say that the first UAV was a stone thrown by a caveman in prehistoric times or perhaps a Chinese rocket launched in the thirteenth century. These “vehicles” had little or no control and essentially followed a ballistic trajectory. If we restrict ourselves to vehicles that generate aerodynamic lift and/or have a modicum of control, the kite would probably fit the definition of the first UAV.

In 1883, an Englishman named Douglas Archibald attached an anemometer to the line of a kite and measured wind velocity at altitudes up to 1,200 ft. Mr. Archibald attached cameras to kites in 1887, providing one of the world’s first reconnaissance UAVs. William Eddy took hundreds of photographs from kites during the Spanish–American war, which may have been one of the first uses of UAVs in combat.

It was not until World War I, however, that UAVs became recognized systems. Charles Kettering (of General Motors fame) developed a biplane UAV for the Army Signal Corps. It took about 3 years to develop and was called the Kettering Aerial Torpedo, but is better known as the “Kettering Bug” or just plain “Bug.” The Bug could fly nearly 40 mi at 55 mi/h and carry 180 lb of high explosives. The air vehicle was guided to the target by pre‐set controls and had detachable wings that were released when over the target, allowing the fuselage to plunge to the ground as a bomb. Also, in 1917, Lawrence Sperry developed a UAV, similar to Kettering’s, for the Navy, called the Sperry‐Curtis Aerial Torpedo. It made several successful flights out of Sperry’s Long Island airfield, but was not used in the war.

We often hear of the UAV pioneers who developed the early aircraft, but other pioneers were instrumental in inventing or developing important parts of the system. One was Archibald Montgomery Low, who developed data links. Professor Low, born in England in 1888, was known as the “Father of Radio Guidance Systems.” He developed the first data link and solved interference problems caused by the UAV engine. His first UAVs crashed, but on September 3, 1924, he made the world’s first successful radio‐controlled flight. He was a prolific writer and inventor and died in 1956.

In 1933, the British flew three refurbished Fairey Queen biplanes by remote control from a ship. Two crashed, but the third flew successfully, making Great Britain the first country to fully appreciate the value of UAVs, especially after they decided to use one as a target and couldn’t shoot it down.

In 1937 another Englishman, Reginald Leigh Denny, and two Americans, Walter Righter and Kenneth Case, developed a series of UAVs called RP‐1, RP‐2, RP‐3, and RP‐4. They formed a company in 1939 called the Radioplane Company, which later became part of the Northrop‐Ventura Division. Radioplane built thousands of target drones during World War II. (One of their early assemblers was Norma Jean Daugherty, later known as Marilyn Monroe.) Of course, the Germans used lethal UAVs (V‐1’s and V‐2’s) during the later years of the war, but it was not until the Vietnam War era that UAVs were successfully used for reconnaissance.

1.2.2 The Vietnam War

The first real use of UAVs by the United States in a combat reconnaissance role began during the Vietnam War. UAVs, such as the AQM‐34 Firebee developed by Teledyne Ryan, were used for a wide range of missions, such as intelligence gathering, decoys, and leaflet dropping.

During the Vietnam War era, UAVs were used extensively in combat, but for reconnaissance missions only. The air vehicles were usually air launched from C‐130’s and recovered by parachute. The air vehicles were what might be called deep penetrators and were developed from existing target drones.

The impetus to operations in Southeast Asia came from activities during the Cuban Missile Crisis when UAVs were developed for reconnaissance but not used because the crisis ended before they became available. One of the first contracts was between Ryan and the Air Force, known as 147A, for vehicles based on the Ryan Firebee target drone (stretched versions). This was in 1962 and they were called Fireflys. Although the Fireflys were not operational during the Cuban crisis, they set the stage for Vietnam. Northrop also improved their early designs, which were essentially model airplanes, to jet‐propelled deep penetrators, but stuck mostly to target drones. The Ryan Firefly was the primary air vehicle used in Southeast Asia.

A total of 3,435 sorties were flown, and most of these (2,873, or nearly 84%) were recovered. One air vehicle, the TOMCAT, successfully completed 68 missions before it was lost. Another vehicle completed 97.3% of its missions of low‐altitude, real‐time photography. By the end of the Vietnam War in 1972, air vehicles were experiencing 90% success rates [1].

1.2.3 Resurgence

At the end of the Vietnam War, general interest in UAVs dwindled until the Israelis neutralized the Syrian air defense system in the Bekaa Valley in 1982 using UAVs for reconnaissance, jamming, and decoys. The Israeli Air Force pioneered several UAVs in the early 1980s. In 1982, United States observers noted Israel’s use of UAVs in Lebanon and persuaded the Navy to acquire a UAV capability. One of the early UAVs acquired by the Navy was the RQ‐2 Pioneer. It was developed jointly by AAI Corporation and Israeli Aircraft Industries and became a very useful air vehicle during Desert Storm for collecting tactical intelligence.

Actually, the Israeli UAVs were not as technically successful as many people believe, with much of their operational success being achieved through the element of surprise rather than technical sophistication. The air vehicle was basically unreliable and couldn’t fly at night, and the data‐link transmissions interfered with the manned fighter communications. However, they proved that UAVs could perform valuable, real‐time combat service in an operational environment.

The United States began to work again on UAVs in August 1971 when the Defense Science Board recommended mini‐RPVs for artillery target spotting and laser designation. In February 1974, the Army’s Material Command established an RPV weapons system management office and by the end of that year (December) a “Systems Technology Demonstration” contract was awarded to Lockheed Aircraft Company, with the air vehicle subcontracted to Developmental Sciences Incorporated (later DSC, Lear Astronics, Ontario, CA). The launcher was manufactured by All American Engineering (later ESCO‐Datron), and the recovery net system by Dornier of the then still‐partitioned West Germany. Ten bidders competed for the program. The demonstration was highly successful, proving the concept to be feasible. The system was flown by Army personnel and accumulated more than 300 flight hours.

In September 1978, the so‐called Target Acquisition/Designation and Aerial Reconnaissance System (TADARS) required operational capability (ROC) was approved, and approximately 1 year later, in August 1979, a 43‐month Full Scale Engineering Development (FSED) contract was awarded to Lockheed as the sole source. The system was given the name “Aquila” and is discussed in more detail at the end of this chapter. For a number of reasons that provide important lessons to UAV system developers, Aquila development stretched out for many years and the system was never fielded.

In 1984, partly as a result of an urgent need and partly because the Army desired some competition for Aquila, the Army started a program called Gray Wolf, which demonstrated, for the first time for a UAV, hundreds of hours of night operations in what could be called “combat conditions.” This program, still partly classified, was discontinued because of inadequate funding.

1.2.4 Joint Operations

The US Navy and Marine Corps entered the UAV arena in 1985 by purchasing the Mazlat/Israeli Aircraft Industries (IAI) and AAI Pioneer system, which suffered considerable growing pains but still remains in service. However, Congress by this time became restless and demanded that a joint project office (JPO) be formed so that commonality and interoperability among the services would be maximized. The JPO was put under the administrative control of the Department of the Navy. This office has developed a master plan that not only defines the missions but also describes the desirable features for each kind of system needed by the services. Some elements of this plan will be discussed in Chapter 2 in the section called “Classes of UAV Systems.”

The US Air Force was initially reluctant to embrace UAVs, notwithstanding their wealth of experience with target‐drone unmanned aircraft. However, this attitude changed significantly during the 1990s and the Air Force not only has been very active in developing and using UAVs for a variety of purposes but also has been the most active of the four US services in attempting to take control of all UAV programs and assets within the US military.

1.2.5 Desert Storm

The invasion of Iraq to Kuwait in 1990–1991 allowed military planners an opportunity to use UAVs in combat conditions. They found them to be a highly desirable asset even though the performance of the systems then available was less than satisfactory in many ways. Five UAV systems were used in the operation: (1) the Pioneer by US forces, (2) the Ex‐Drone by US forces, (3) the Pointer by US forces, (4) the “Mini Avion de Reconnaissance Telepilot” (MART) by French forces, and (5) the CL 89, a helicopter UAV, by British forces.

Although numerous anecdotal stories and descriptions of great accomplishments have been cited, the facts are that the UAVs did not play a decisive or a pivotal role in the war. For example, the Marines did not fire upon a single UAV‐acquired target during the ground offensive according to a Naval Proceedings article published in November 1991 [2]. What was accomplished, however, was the awakening in the mind of the military community of a realization of “what could have been.” What was learned in Desert Storm was that UAVs were potentially a key weapon system, which assured their continuing development.

1.2.6 Bosnia

The NATO UAV operation in Bosnia was one of surveillance and reconnaissance. Bomb‐damage assessment was successfully accomplished after NATO’s 1995 air attacks on Bosnian‐Serb military facilities. Clearly shown in aerial photographs are Serbian tanks and bomb‐damaged buildings. Night reconnaissance was particularly important as it was under the cover of darkness that most clandestine operations took place. The Predator was the primary UAV used in Bosnia, flying from an airbase in Hungary.

1.2.7 Afghanistan and Iraq

The war in Iraq (which lasted from 2003 to 2011) has transformed the status of UAVs from a potential key weapons system searching for proponents and missions to their rightful place as key weapon systems performing many roles that are central to the operations of all four services. At the beginning of the war, UAVs were still under development and somewhat “iffy,” but many developmental UAVs were committed to Operation Iraqi Freedom.

The Global Hawk was effectively used during the first year despite being in the early stages of developmental. The Pioneer, the Shadow, the Hunter, and the Pointer were used extensively.

The Marines flew hundreds of missions using Pioneers during the battle for Fallujah in 2004 to locate and mark targets and keep track of insurgent forces. They were especially effective at night and could be considered one of the decisive weapons in that battle.

The armed version of the Predator, mini‐UAVs such as the Dragon Eye, and a wide range of other UAV systems have been used on the battlefields of Afghanistan and Iraq and have proven the military value of UAVs.

Predator UAVs have been operational in Bosnia since 1995 and as part of Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom, flying more than 500,000 flight hours on over 50,000 flights. It is interesting to know that in 2002, an Iraqi MiG‐25 intercepted an air‐to‐air equipped Predator. Both fired missiles at each other, but MiG‐25 evaded but Predator was shot down.

During Operation Iraqi Freedom, the Global Hawk flew 15 missions, collecting over 4,800 images from March 18 to April 23, 2003.

1.2.8 Long‐Range Long‐Endurance Operations