Radar Principles for the NonSpecialist
Radar Principles for the Nonspecialist, Third Edition continues its popular tradition: to distil the very complex technology of radar into its fundamentals, tying them to the laws of nature on one end and to the most modern and complex systems on the other. It starts with electromagnetic propagation, describes a radar of the utmost simplicity, and derives the radar range equation from that simple radar. Once the radar range equation is available, the book attacks the meaning of each term in it, moving through antennas, detection and tracking, radar crosssections, waveforms and signal processing, and systems applications. At the finish, the reader should be able to do an acceptable, first order radar design and to critique the design of others. Students, engineers, scientists and managers will benefit from this book. The more noticeable enhancements to the third edition are the additions of equation numbers, more numerical examples, tables and figures showing many of the concepts numerically, and exercises for almost all of the concepts. These enhancements make the book easier to learn from and easier to teach out of.
Other keywords: radar lore; ECM; electronic countermeasures; radar potentials; radar range equation; waveforms; non specialist; tracking; antennas; radar principles; systems applications; signal processing; radar cross section; elementary electromagnetics; radar limitations
 Book DOI: 10.1049/SBRA032E
 Chapter DOI: 10.1049/SBRA032E
 ISBN: 9781891121340
 eISBN: 9781613531594
 Format: PDF

Front Matter
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1 Elementary Electromagnetics and the Radar Range Equation
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Chapter 1 discusses some fundamentals of radio waves from Faraday, Maxwell, and Hertz; putting together a simple radar and discussing its principal parts; deriving the radar range equation from first principles; discovering special features of surveillance and tracking radars. Radar is an acronym for RAdio Detection And Ranging. Before we develop the principles of radar, the authors will review the characteristics of radio waves.

2 Antennas
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An antenna is the mechanism by which the electromagnetic signal is radiated and received. For radars (although not necessarily for antennas in other electromagnetic applications), it is essential that the antenna enhance performance. A radar antenna has three roles: to be a major contributor to the radar's detection performance, to provide the required surveillance, and to allow measurements of angle of sufficient accuracy and precision. A reasonable place to begin is with the two expressions used to derive the radar range equation: antenna gain and effective area. For a transmitting antenna, antenna gain is simply a measure of how much focusing of the transmitted waveform is being accomplished by the antenna. Focusing is the ability to add up energy preferentially. Energy arriving at the antenna from a given direction is integrated; that arriving from elsewhere is not. It is assumed that energy arriving at the antenna is in the form of plane waves, that is, the phase of the arriving energy is constant over any plane perpendicular to the direction of arrival.

3 Detection and Tracking
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Assume that radars having some of the parameters described in the preceding chapters can be built and operated. A vitally important question is how the operator decides when he sees a target. He has found out quickly from experience that he can turn up the gain on his radar display and completely fill his field of view with false targets (noise), or he can turn down the gain and eliminate all targets. How does he decide where to set the threshold to optimize his ability to detect? Likewise, how do we set the threshold for the automatic detection systems used by the majority of modern radar systems?

4 Radar Cross Section
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Radar cross section (RCS) is a measure of the electromagnetic energy intercepted and reradiated at the same wavelength by any object. The dimensions are those of an area, usually square meters (m^{2}) or decibels relative to a square meter (dBsm). The relationship between square meters and dBsm. The RCS of an object is a complex combination of multiple factors: size, shape, material, edges, wavelength, and polarization. Simple objects tend to have a single, or few, scattering sources. Complex objects (such as airplanes) tend to have multiple scattering sources (e.g., nose, fuselage, inlet, wing root, wing, and so forth). Thus, for complex objects, the RCS is the complex (amplitude and phase) combination of contributions from each scattering source.

5 Waveforms and Signal Processing
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This chapter highlights the following: analyzing the simple pulse in both time and frequency domains; matched filtering to optimize signaltonoise ratio; measuring range with a radar; the Doppler phenomenon; measuring range rate with Doppler ; acceleration measurements; measuring angle; pulse compression; features of FM chirp; time sidelobes in compressed pulses and weighting functions to mitigate them; pulse burst waveforms; ambiguities and their elimination; signal processing, basic receiver chain; and integration and Doppler processing digital filters.

6 Electronic Countermeasures (ECM)
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The paper is about defining and discussing ECM and ECCM. Developing the basic relationships in mainlobe jamming. Expanding to the sidelobe jamming case. Sidelobe canceling, concepts of adaptivity. The low probability of intercept (LPI) radar and radar warning receivers (RWRs). Active ECM techniques and their countercountermeasures. Passive ECM techniques and their countercountermeasures.

7 Systems Applications
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Radar is pervasive in modern life. Although military applications dominate, at least as far as big complex systems are concerned, nonmilitary applications are legion. Many mediumsized private boats and airplanes are radar equipped, the former for navigation and the latter for obtaining accurate altitude. Commercial airlines and ships are almost all radar equipped. Radars are much used in law enforcement. Traffic officers have them, as do the border patrol and others. The Federal Aviation Administration operates at least 40 large radars and numerous small ones to keep track of the nation's air traffic, with the higher altitudes being under radar control at all times. Many companies and individuals with highvalue facilities use radars for security.

8 Loose Ends of Radar Lore
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Several other brief quantitative notions and a list of rules of thumb should be included in any set of radar fundamentals. Some are good for general daytoday use; others are important to detailed radar design calculations. They are pulled together in this chapter without concern for their relevance to each other and only because they are valid radar lore.

9 Radar Potentials and Limitations
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To summarize, the qualities that make radar essential to modern life also limit its utility. The fact that it furnishes its own illumination makes it valuable for obtaining almost instantaneous range and range rate data on targets and for night operations against passive or noncooperative targets, but this limits its ultimate range. The fact that the frequencies at which radars operate can penetrate bad weather, smoke, and dust and can see over the Earth's horizon makes them essential to emergency operations, particularly military operations, but prevents them from obtaining the high resolution they need to get finegrained images. The vigorous application of new technology and human ingenuity will tend to expand radar's applications and mitigate its shortcomings. However, the natural laws cannot be overcome, inevitably consigning radar to its niche: an interesting and important technology with multifaceted but limited uses.

Appendix 1: Conversion to Decibels
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Because radar engineers often deal in power, decibels relative to a watt or decibels relative to a milliwatt are used. Another common use of decibels is for RCS, decibels relative to a square meter. Some approximate decibel values usually memorized by radar people are shown in this appendix.

Appendix 2: The Radar Spectrum
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Appendix 2 provides a diagram of the radar spectrum.

Appendix 3: Fourier Series and Transforms
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Working in the field of heat transfer in the early nineteenth century, Jean B. S. Fourier found that virtually all functions of time, particularly repetitive ones, could be described in a series of sine and cosine waves of various frequencies and amplitudes. His work has been described as one of the most elegant developments in modern mathematics. Whatever its stature for the world, the benefits for the radar engineer are epic.

Appendix 4: Answers to Exercises
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This appendix provides the answers (rounded to two decimal places) to the questions set at the end of each chapter.

Appendix 5: Glossary
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This glossary provides assistance in understanding terms used in this book. There may be more general, more specific, or entirely different meanings for these terms when they are used elsewhere.

Back Matter
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Supplementary material

Supplementary Material for Toomay "Radar Principles for the NonSpecialist, 3rd edition", SBRA032

The supplementary material for this book consists of an errata sheet.
Solutions to exercises are available for instructors who have adopted this text for their classes. Please email [email protected] with your details for further information.

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