A comprehensive resource that explores electromagnetic compatibility (EMC) for aerospace systems
Handbook of Aerospace Electromagnetic Compatibility is a groundbreaking book on EMC for aerospace systems that addresses both aircraft and space vehicles. With contributions from an international panel of aerospace EMC experts, this important text deals with the testing of spacecraft components and subsystems, analysis of crosstalk and field coupling, aircraft communication systems, and much more. The text also includes information on lightning effects and testing, as well as guidance on design principles and techniques for lightning protection.
The book offers an introduction to E3 models and techniques in aerospace systems and explores EMP effects on and technology for aerospace systems. Filled with the most up-to-date information, illustrative examples, descriptive figures, and helpful scenarios, Handbook of Aerospace Electromagnetic Compatibility is designed to be a practical information source. This vital guide to electromagnetic compatibility:
• Provides information on a range of topics including grounding, coupling, test procedures, standards, and requirements
• Offers discussions on standards for aerospace applications
• Addresses aerospace EMC through the use of testing and theoretical approaches
Written for EMC engineers and practitioners, Handbook of Aerospace Electromagnetic Compatibility is a critical text for understanding EMC for aerospace systems.
REINALDO J. PEREZ, PHD, MBA is a hardware and software engineer with 30 years of industrial experience in electronic engineering design and development, reliability engineering, electromagnetic compatibility, software engineering, and applied research. He has participated in the reliable design, development, manufacture and tests of avionics hardware for many aerospace applications at the board, assembly, subsystems, and system levels. He has been involved in IEEE for many years and has occupied many managerial and technical positions in IEEE. He has published extensively in peer reviewed journals and conferences in the fields of electrical, software, and aerospace engineering. He has taught as an adjunct several engineering disciplines at engineering colleges.
Introduction to E3 Models and Techniques in Aerospace Systems
1.1 Introduction and Topics of Interest
This chapter renders an overview and perspective of electromagnetic compatibility (EMC) and electromagnetic environmental effects' (E3) theoretical considerations for current, near-term, and future aerospace systems. Our starting point extends in part from the current MIL-STD-464C, MIL-STD-461, and MIL-STD-3023 (all discussed in Section 1.5) baseline threats and technologies that include analytical models, testing techniques' measurements, shielding, numerical techniques, transients, antennas, power modulators, printed circuit board, cables, subsystems, individual limited-size systems, etc. By providing relevant academic and industrial educational resources (conferences, courses, journals, etc.), the EMC and E3 community supports the creation of standards and the development of new components and systems.
The role of EMC and E3 for aerospace systems is to not only maintain high standards, but also to improve the reliability and survivability of complex time-dependent networks that are susceptible to catastrophic failures. Survivability is enhanced by increasing the timeliness of delivery and reliability of long messages, improving reception for multiple multicast networks during link failure, and increasing robustness of heterogeneous networks through advanced communication techniques such as network coding.
It is absolutely essential that certified aerospace EMC and E3 hardware and software are trustworthy. In addition to this mainstream bread-and-butter activity, it is also desirable and necessary to probe in the near term and future and prepare the theoretical foundations upon which to build robust analytical and testing techniques to meet new requirements. The need for new EMC and E3 techniques arises because of increasingly complex emerging systems that, in large measure, will focus on:
- Testing techniques for autonomous systems that rely on dimensional analyses and stability theory
- Air-to-ground and space-to-ground and space-to-atmosphere communication and radar networks that contain combinations of random nondirect and direct communication electromagnetic propagation links
- New-generation aircraft that employ increasingly susceptible electronic components that may require advanced nonlinear control analyses and control systems, and advanced signal analyses that can identify and manage chaos signals and high-power microwaves (HPM) waveforms.
We assert that the EMC and E3 technologies discussed in detail in Sections 1.2-1.5 meet the aforementioned "a-to-d" challenges.
1.1.2 Autonomous Systems
As pointed out in Section 1.2, an autonomous system is composed of three major functions: perception-sensing the environment, decision-making-selecting the best course of action, and execution-implementing the best course of action. The ultimate goal of an autonomous system is to provide the operating conditions and performance standards for each decision-making algorithm. Complex adaptive systems (CAS) that will include both human and software components need to be developed and tested to ensure that the autonomous system will perform its function as required within the system as a whole. Related control theory is routinely used to design electromechanical algorithms employed in the system while ensuring that the algorithms work effectively in a stable manner in response to their stimulation and interactions with other components in the overall system.
Figure 1.1 shows models of autonomous systems currently under development. The elements of these autonomous systems are discussed in Section 1.2. These systems must operate in the presence of strong electromagnetic interference, which plays a critical role in system performance since they are often the principal generator of unwanted electromagnetic signals. The creation of unwanted signals due to interference may require nonlinear control functions, which create undesirable complications.
Figure 1.1 Models of the autonomous system.
1.1.3 Networks of Coupled Air and Space Systems
Today, the number of nodes in a network can be in the hundreds of thousands to over a million. Current networks have great connectivity for large numbers of nodes and include a mixture of deterministically positioned nodes, and randomly located nodes spread out over land, sea, atmosphere, and space. A key example is the class of mobil ad hoc networks (MANETs) involving directed and nondirected random graphs. Variables of modern networks include number of nodes and links, the probability density function of links connected to nodes, the probability density function of distance between node pairs, and selected system-unique parameters. Figure 1.2 illustrates a model of a MANET-type land system coupled to an airborne system having a relatively small (e.g., 1-100) number of platforms and possibly a few satellites.
Figure 1.2 Illustration of land/airborne communication system.
Intentional electromagnetic interference effects (IEMIs) range from direct jamming and interference of nodes to the creation of fading dispersive channels that can limit both the coherence time and the coherence bandwidth. All these effects can reduce the information rate and, if bad enough, can cause the network to break into isolated clusters-possibly the most serious adverse effect. It is necessary to define the mathematical structure of these networks and the mathematical tools that are necessary to perform the communication survivability assessments. Section 1.3 discusses these issues in more detail.
1.1.4 EMC Considerations of Chaos and Related Waveforms
A technology that needs to be better understood in the aerospace EMC and E3 community is a spectrum of anomalous waveforms that are embraced by the term "chaos," discussed in Section 18.104.22.168. There is currently much interest in quantifying, predicting, and measuring these effects on electronic and hybrid control systems, power electronics and power supplies generated by high-power electronics (HPE), and high power microwaves (HPM), which can cause temporary upset to permanent damage. These unwanted signals arise in multidimensional nonlinear dynamic systems and can manifest themselves as being extremely sensitive to initial conditions, splitting apart (unbounded), exhibiting unanticipated periodic/quasiperiodic motion and strange attractors, creating power spectrum with continuous parts, etc. Unfortunately, in many laboratory cases, the unwanted signals are not recognized as chaos but as "not understood" interference.
Researchers attempt to explain observations in terms of system variables such as microwave frequency, pulse duration, pulse repletion rate, peak power, average power, type of equipment, computer clock rate, and the number of components used in the experiment. Proposed connections between chaos and stochastic processes have been suggested with only modest success. As systems become more complicated, it will be necessary to have measurement algorithms that predict aerospace performance, especially for autonomous systems.
Much of what we have sketched out in this section can be visualized with the aid of Figure 1.3. This figure depicts a single system under attack by an HPE threat such as HPM, IEME, and chaos. The Xs are the assumed spots where the significant interactions are assumed to occur. Using the mathematical tools and theories developed in Section 1.5, we will be able to predict the output signal and the effect on critical aeronautical systems.
Figure 1.3 Example of electronic threat on the electronic system.
1.1.5 EMC Effects on and Technology for Aerospace Systems
22.214.171.124 Testing and Hardening Aerospace Systems
Section 1.5 embraces traditional advanced topics used in aerospace systems such as nonlinear control systems, multiple input multiple output (MIMO) control systems, and scaling theory and testing. While these are not necessarily new topics, their technologies need to be kept current in lieu of advancements being made in information theory, nanomaterials, metasurfaces, etc. Our goal is that given a testing resource of several facilities that collectively cover the spectrum of threat waveforms applied to different targets over defined time interval, what is the most effective way by which we can assess the hardness, survivability, and reliability of the system. As a starting point, we assume that we know (1) the baseline cost and testing time for testing a single hypothetical object against a specified threat waveform in every relevant facility and (2) the total time for testing in a specified facility. The baseline threats include but are not limited to those identified in MIL-STD-461, MIL-STD-464C, and MIL-STD-3023, but do not include chaotic waveforms. In addition, special testing consideration may need to be given for simulating aircraft stability under threat conditions.
The primary goal of Section 1.5 is to provide techniques that will reduce testing and hardening costs while...