bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Modification of Space Materials
Authors: Kleiman Jacob I. 
Published: December 2010

AbstractSurface engineering techniques are being used extensively in the aerospace and space industries as well as a variety of other industries to develop, maintain, or change a wide range of functional properties, including physical, chemical, electrical, electronic, magnetic, mechanical, wear‐resistant and corrosion‐resistant properties. An overview of the present, state‐of‐the‐art, situation in the field of surface modification of space materials is presented. A number of surface modification technological solutions that differ from the traditional protective coating approaches are discussed that change the surface properties of treated materials thus protecting them from the hazards of low earth orbit (LEO) and geostationary orbit (GEO) environments or impairing new functional properties to space materials used in LEO/GEO, with examples of their testing, characterization and applications provided.
Space Environment Simulation and Materials Testing
Authors: Tighe Adrian P. 
Published: December 2010

Abstract
This chapter describes the design and types of ground‐based test facilities used to simulate the effects of the space environment on materials. The ability of the facilities to replicate the environment is discussed. First, an overview is given of the design and operational requirements common to most types of facility, including the design of the vacuum facility, the requirements for the test environment, sampling handling and storage requirements, as well as cleanliness and contamination control requirements. Various measurement philosophies are also discussed. The different test facilities most commonly used are described, covering vacuum outgassing, atomic oxygen simulation, thermal testing, electromagnetic radiation and charged particle testing, micrometeoroid and orbital debris simulation, and testing in a pressurized environment. In each case, the facility design, test standards, and data analysis methodology are discussed. Other environments that are also mentioned briefly are planetary environments, spacecraft launch and re‐entry environments, synergistic test environments, and on‐ground environments.
Cruise Performance of Fixed‐wing Aircraft
Authors: Young Trevor M. 
Published: December 2010

AbstractMethods are presented for the determination of the range and endurance of fixed‐wing airplanes with thrust‐rated powerplants (e.g. turbo‐jets and turbofans) and power‐rated powerplants (e.g. piston‐propeller and turbo‐propeller). Range and endurance integral expressions are derived, and numerical techniques for their evaluation outlined. Analytical solutions for the integral expressions are presented based on the following sets of assumptions: (i) cruise at constant height and constant lift coefficient, (ii) cruise at constant airspeed and constant lift coefficient (i.e. the Breguet solution), and (iii) cruise at constant height and constant airspeed. There are two conventions for the definition of the specific fuel consumption (SFC): it can be defined either in terms of the mass flow rate or the weight flow rate of the fuel. This leads to two sets of expressions for range and endurance; both conventions are covered in this chapter. The determination of the fuel required for an airplane to fly a complete mission – which includes the takeoff, climb, cruise, descent, approach and land – is a relatively complex calculation; however, considerable insight into an airplane's range is achieved by studying the cruise segment in isolation – this approach is outlined.
Static Lateral Stability
Authors: Filippone Antonio 
Published: December 2010

Abstract
This chapter deals with the static lateral stability and trim conditions for a fixed‐wing aircraft having a conventional geometry (wing, horizontal, and vertical tail plane). The aircraft is considered as a rigid body. The basic control systems are shown for a conventional vehicle consisting of a wing with aileron, a horizontal tail with elevator, and a vertical tail with rudder. The simple case of a banked turn is presented.Then the pitching moment equations are derived for the wing alone and the full aircraft. Two particular cases are considered: (i) minimum control speed in air for a flight with asymmetric thrust; (ii) aircraft in straight rolling motion without inertia coupling.The lateral stability conditions in roll are derived and the main parametric effects are discussed.
Longitudinal Dynamic Stability
Authors: Yechout Thomas R. 
Published: December 2010

Abstract
Longitudinal dynamic stability addresses the time history of motion following a disturbance in pitch. This chapter summarizes the most commonly used approach to analyze the two predominant longitudinal dynamic stability modes, usually referred to as the short period and phugoid. A review of the development of the six non‐linear aircraft equations of motion, along with a review of the three linearized longitudinal equations is a realistic prerequisite for the reader. A significant degree of importance is placed on obtaining excellent longitudinal dynamic stability characteristics in an aircraft design, with special emphasis on the short period mode, since the pilot's ability to accomplish tracking and maneuvering tasks is directly affected by these characteristics. In recent decades, baseline aircraft dynamic stability characteristics have been typically compromised in aircraft designs. This design compromise has been chosen in favor of decreased drag to obtain performance improvements such as increased range, endurance, and turning performance, with the knowledge that feedback control systems will be added to the design to “modify” the baseline dynamic stability and obtain excellent dynamic stability or handling quality characteristics.
Rotary‐Wing Dynamic Stability
Authors: Lee David A. 
Published: December 2010

Abstract
The dynamic stability of a rotary‐wing aircraft is assessed by predicting and observing the aircraft motion following a disturbance from trimmed flight. Varying time scales for the dynamic stability assessment separate the stability modes. A short time scale of 2–3 s highlights the control response. A longer time scale up to a maximum of typically 60 s describes the “classical” dynamic stability. For a conventional helicopter, the effects of the main rotor dominate the control response and dynamic stability characteristics, although other key contributions must be considered. These contributions can be quantified via stability and control derivative sets enabling estimates of engineering parameters. Comparisons can be made of these parameters against handling quality metrics to predict handling quality rating (HQR) levels. Flight testing involving longitudinal and lateral‐directional control response tests and dynamic stability tests are relatively straightforward but will always be supported by mission‐related handling tasks, where HQR values are assigned by qualified test pilots. Cross‐coupling assessments are a significant feature of control response and dynamic stability testing. The principles and practices of dynamic stability modeling and flight testing have applications to unconventional rotary‐wing configurations but only after cautious appraisal of the likely outcomes.
Fixed‐Wing Control and Handling Qualities
Authors: Hess Ronald A. 
Published: December 2010

AbstractAn introduction into the control and handling qualities of fixed‐wing aircraft is presented. Military handling qualities specifications are discussed followed by examples of specification requirements for aircraft longitudinal and lateral/directional modes of motion. Lower‐order equivalent systems are introduced as a means for accommodating the higher‐order, nonclassical dynamics that accompany the introduction of stability and command augmentation systems. Other frequency domain handling qualities criteria such as bandwidth/phase delay are introduced. Techniques that have their basis in control theoretic models of the human pilot complete the chapter.
Rotary‐Wing Control and Handling Qualities
Authors: Cooke Alastair K. 
Published: December 2010

Abstract
The conventional helicopter is controlled by altering the pitch of the rotor blades (feather angle) in a suitable manner to change the magnitude and, in the case of the main rotor, alter the orientation of the thrust vector. The orientation of the main rotor should ideally mirror the position of the cyclic stick in the cockpit and this is usually achieved by providing a suitable mix of longitudinal and lateral feather commands. A study of the flapping dynamics provides insight into how this mixing is accomplished for rotors with different amounts of flapping stiffness and hinge offset.
As the handling qualities of the typical helicopter are less than ideal most are fitted with a command and stability augmentation system which permits some tailoring of the response characteristics. The determination of the best mix of handling qualities was the subject of much international research in the late twentieth century; resulting in the publication of the USAMC's Technical Report ADS‐33E‐PRF, “Handling Qualities Requirements for Military Rotorcraft,” which is considered to be a seminal document by many within the rotorcraft community.
Special Features of Guided Weapon Stability and Control
Authors: Bray Derek 
Published: December 2010

Abstract
The fundamental principles of aerodynamic stability and control are just as applicable to guided weapons (GWs) as to the more commonly understood fixed‐wing aircraft. The different operational characteristics, however, result in distinct nuances between the two classes. For instance, many GWs, especially those designed for fighter aircraft attack, have relatively high lateral acceleration requirements. The majority of GWs also operate in the supersonic regime, often well above the speeds typically encountered by even the fastest aircraft. Additionally, most GWs are of axisymmetric designs. All of this, and more besides, means that GW stability and control merits specialized treatment.
This chapter provides a detailed overview and analysis of aerodynamic stability and control, as applied specifically to the case of GWs (missiles). The principal subjects covered in this chapter include trim, static and dynamic stability considerations, stability derivatives, airframe configurations, and aerodynamic control methods.
Nonlinear Flight Control Systems
Authors: Kim Seungkeun , Tsourdos Antonios , White Brian A. 
Published: December 2010

AbstractThis chapter aims to provide the reader with a basic understanding of nonlinear control theory and its applicability to flight control system design. To begin with the limitation of the gain‐scheduling technique widely used for flight control is discussed, and subsequently the taxonomy of the system dynamics is touched in order to help understand how the model characteristics affects the nonlinear controller design. Then nonlinear control theories attractive to flight control system are briefly introduced with tutorials and control law derivations based on aircraft dynamics, which includes feedback linearization, sliding mode control, backstepping control, receding horizon control and other approaches. This chapter finishes with giving conclusions and perspectives of the nonlinear flight control systems.
Flight Formation Control
Authors: Innocenti Mario , Pollini Lorenzo 
Published: December 2010

AbstractThis chapter presents an overview of the main issues relating to guidance and control of aircraft flying in a formation. Formation flight is a demanding task when performed manually, and it is a challenge for the flight control engineer, when performed in an automated fashion or by autonomous unmanned vehicles. The chapter focuses primarily on the investigation of possible formation structures to be used in an operational environment, with emphasis on optimization with respect to data information transfer among the elements (nodes) of the formation itself. The final objective is the capability of maintaining a formation in the presence of a failure of one of the vehicles/components, such as the loss of an aircraft, with a high degree of autonomy and possibly without intervention from ground and/or command operators. Although the emphasis is on unmanned aircraft, the principles could be extended to automated manned formation flight as well.
Antennas and Electromagnetic Wave Propagation: Radar, Seekers and Sensors, Tracking, and Target Recognition
Authors: Hall Peter S. 
Published: December 2010

AbstractRadars use controlled beams of electromagnetic energy to detect or track targets. The antenna is the device that controls the energy projection. It is necessary to study antenna types and designs to understand the limitations on this control and, in particular, how narrow a beam can be at the operating frequency. In general, the higher the frequency, the narrower the beamwidth. In addition, the properties of the atmosphere can affect the propagation of the energy, and in general the energy is more heavily attenuated at higher frequencies. It is clear that one cannot easily have long range and narrow beamwidths from the same equipment, and thus the design of the antenna and an appreciation of radio wave propagation become central to the operation of radar systems. This chapter gives an overview of how antennas operate, the various types of antennas that have been developed and describes the principles of radio wave propagation.
Radar Basics and Applications
Authors: Stove Andrew G. 
Published: December 2010

Abstract
The chapter provides a brief outline of the theory of radar and illustrations of the range of applications of radar in aerospace systems. An outline of the derivation and application of the radar range equation is provided, together with basic detection curves and rules of thumb to use these in simple performance calculations. The effects of clutter and multipath are also briefly discussed. Besides the discussion of conventional radar designs, synthetic aperture radars and electronically scanned arrays are briefly introduced. Applications of ground‐based radars to observe aircraft and of airborne radars are briefly described. A very brief introduction to countermeasures to radar is also included. It is intended that this introduction will be supplemented by the more detailed discussion of many of these topics in other chapters of the encyclopedia.
Backscatter from Land and Sea
Authors: Watts Simon , Ward Keith D. 
Published: December 2010

Abstract

An important factor influencing the performance of radar systems is the nature of the signal scattered back from the land and sea. Much research has been undertaken on this topic of radar clutter since the invention of radar, and there remains much to be done to understand clutter and its effect on radar behavior. This chapter presents an overview of the current state of knowledge and gives detailed examples of some aspects. First, the calculation of radar backscatter is considered using a description of the scattering surface (the land or sea) and the equations governing electromagnetic fields. It is shown that in order to obtain useful quantitative results it is necessary to apply approximations to the surface description and the scattering calculations, and this limits the progress that can be made. For this reason many of the advances to date have been made through analysis of radar data. Radar clutter characteristics derived from this analysis are shown here, such as normalized radar cross section (

), amplitude statistics, temporal fluctuations, the Doppler spectrum, and spatial correlation. This is followed by a description of these characteristics for land and sea clutter, and how they change with radar parameters, geometry, and environmental conditions.
Synthetic Aperture Radar
Authors: Moccia Antonio 
Published: December 2010

Abstract
Since its appearance in the 1950s, synthetic aperture radar (SAR) has been experiencing a continuous growth in systems, performance, and applications. Thanks to its possibility of any‐weather and any‐time operation, SAR became rapidly a primary remote sensing system for Earth and planetary observation, and, today, a widening of its application in more demanding fields, such as natural hazards or surveillance, is noticeable: as an example, by using airborne SAR, it is possible to obtain 3‐D images of a surface with centimeter resolution, detect surface variation, and indicate moving targets. This chapter intends to give an overview of SAR operation and performance, with special emphasis on aspects related to aerospace engineering. Basic geometry to define SAR observation is introduced, illustrating how dynamics of the aerospace platform embarking SAR is fundamental to image formation. It is explained how SAR operates by exploiting the range‐Doppler approach and how a noteworthy increase of azimuth resolution is achievable. Multistatic configurations are then presented with special emphasis on cross‐track and along‐track SAR interferometry, showing how digital elevation model and moving target identification can be obtained. The principles of SAR processing are outlined, and the orders of magnitude of overall configurations and achievable performance are given. Finally, a brief introduction to future SAR systems is given, discussing potentialities of multiple antennas distributed on aerospace platforms flying in formations.
Radar Missile Seekers
Authors: Baker Chris J. , Zyweck Anthony 
Published: December 2010

AbstractModern missiles represent an example of a highly integrated set of subsystems that all interact cooperatively to guide the missile to its target. The key to intercepting moving targets is the missile seeker, and for all weather, day/night, and long‐range performance, the RF seeker is the preferred option. RF seekers are often viewed as “little” airborne intercept (AI) radars. There are considerable functional differences between RF seekers and their larger cousins because of the different requirements for missile guidance when compared to airborne surveillance. This chapter begins by reviewing the characteristics of a modern RF missile, which impact the RF seeker requirements. The role of the RF seeker is then explored and differences between RF seekers and AI radars are highlighted. The key figures of merit for RF seeker performance are reviewed and their effects on modern RF seeker design are explained. There have been many different RF seeker designs over the years but the modern active coherent seeker is currently prevalent. The key aspects of a generic active RF seeker configuration are discussed. Finally, some advanced RF seeker trends are discussed. The benefits of increased operating frequency and instantaneous bandwidth are covered as well as the emerging requirement to reduce seeker signatures for improved effective engagement range and compatibility with low observable launch platforms. Several aspects of seeker design that improve electronic protection are also discussed.
Global Navigation Satellite Systems
Authors: Axelrad Penina 
Published: December 2010

Abstract
A Global Navigation Satellite System (GNSS) enables continuous positioning anywhere on or near the Earth surface by means of radio signals transmitted from orbiting satellites. The system comprises a constellation of about 20 or more satellites, a network of ground stations for monitoring and control of the satellites, and an unlimited number of users who passively receive the signals and employ them for positioning and other applications. GNSS satellites transmit carrier signals in the range of 1.1–1.8 GHz, which are modulated by digital codes, termed pseudo‐random noise (PRN) codes. The codes are selected so as to enable all satellites in the constellation to transmit at the same frequency with minimal interference, and to permit range measurements to be made. Given information on the satellite locations and measurements of range to at least four satellites, a receiver on or near the surface of the Earth can solve for its three dimensional position and time. GNSS is widely used for navigation and positioning of aircraft and satellites. Aviation users in particular, have very stringent requirements that are driving current augmentation and modernization efforts.
High‐Precision Three‐Axis Pointing and Control
Authors: Bayard David S. 
Published: December 2010

AbstractThis chapter discusses spacecraft precision three‐axis attitude control based on reaction wheel actuation and star tracker and gyro sensing. The nonlinear dynamics and kinematics associated with a rigid body withnreaction wheels are presented. A linearized controller usingnreaction wheels is designed that stabilizes the three‐axis attitude dynamics, while commanding desired spacecraft attitude, rate, and acceleration. Properties of the attitude controller are discussed including its stability, command tracking, and disturbance rejection properties. Sensor errors and reaction wheel disturbances are discussed as the two main sources of pointing error. Methods are presented to model these errors and to deal with their effects.
Efficient Models of Multi‐body Dynamics
Authors: Skelton Robert E. 
Published: December 2010

AbstractSpacecraft can be large and flexible, with articulated elements. Multi‐body models of these dynamics are often used in space structure design and analysis. This chapter presents multi‐body dynamics in a new form, as amatrixdifferential equation, rather than the traditionalvectordifferential equation. The model has a constant mass matrix, and the equations are non‐minimal. A specific focus of this chapter is tensegrity systems. A tensegrity system requires prestress for stabilization of the configuration of rigid bodies and tensile members. This chapter provides an efficient model for both static and dynamic behavior of such systems, specialized for the case when the rigid bodies are axisymmetric rods.
Launch Vehicle Operational Environments
Authors: Kabe Alvar M. , Kendall Randolph L. 
Published: December 2010

AbstractThere are numerous operational environments that a launch vehicle and its payload are subjected to during launch and flight. These include both external environments, such as ground wind loading and atmospheric pressure, as well as self‐induced, such as vibration due to engine thrust. The relative influence of these environments varies significantly during the different phases of flight, necessitating multi‐disciplinary design and analysis approaches. This chapter describes the various environments, as well as the approaches used to establish the viability of launch vehicle and spacecraft designs to survive the launch and flight environments. In addition, day‐of‐launch operational considerations for flying a launch vehicle safely through the atmosphere, while staying within its structural and control system design limits are also discussed.