Principles of modern radar edited by jerry l eaves, edward k reedy

PRINCIPLES OF MODERN RADAR PRINCIPLES OF MODERN RADAR Edited by Jerry L Eaves and Edward K Reedy CHAPMAN & HALL I ® J:f International Thomson Publishing New York' Albany' Bonn • Boston' Cincinnati Detroit London' Madrid' Melbourne Mexico City • Pacific Grove • Paris • San Francisco • Singapore Tokyo • Toronto • Washington Copyright" 1987 by Van Nostrand Reinhold Softeover reprint of the hardcover 1st edition 1987 This edition published by Chapman & Hall, New York For more information contact: Chapman & Hall I 15 Fifth Avenue New York, NY 10003 Chapman & Hall 2-6 Boundary Row London SEI 8HN England Thomas Nelson Australia I02 Dodds Street South Melbourne, 3205 Victoria, Australia Chapman & Hall GmbH Postfach 100 263 0-69442 Weinheim Germany International Thomson Editores Campos Eliseos 385, Piso International Thomson Publishing - Japan Hirakawaeho-cho Kyowa Building, 3F Col Polanco 1-2-1 Hirakawacho-cho 11560 Mexico D.F Mexico Chiyoda-ku, 102 Tokyo Japan International Thomson Publishing Asia 221 Henderson Road #05-10 Henderson Building Singapore 0315 All rights reserved No part of this book covered by the copyright hereon may be reproduced or used in any form or by any means graphic, electronic, or mechanical, including photocopying recording, taping or information storage and retrieval systems without the written permission of the publisher XXX 01 00 99 98 97 Library of Congress Cataloging-in-Publication Data Principles of modem radar Includes index ISBN-I3: 978-1-4612-9170-1 e-ISBN-I3: 978-1-4613-1971-9 001: 10.1007/978-1-4613-1971-9 I Radar I Eaves, Jerry L II Reedy, Edward K TK6575.P74 1987 86-11144 CIP 621.3848 Visit Chapman & Hall on the Internet http://www.chaphaILcomichaphaILhtml To order this or any other Chapman & Hall book, please contact International Thomson Publishing, 7625 Empire Drive, Florence, KY 41042 Phone (606) 525-6600 or 1-800-842-3636 Fax: (606) 525-7778 E-mail: order@chaphall.com For a complete listing of Chapman & Hall titles, send your request to Chapman & Hall, Dept BC, 115 Fifth Avenue, New York, NY 10003 PREFACE This book, Principles of Modern Radar, has as its genesis a Georgia Tech short course of the same title This short course has been presented annually at Georgia Tech since 1969, and a very comprehensive set of course notes has evolved during that seventeen year period The 1986 edition of these notes ran to 22 chapters, and all of the authors involved, except Mr Barrett, were full time members of the Georgia Tech research faculty After considerable encouragement from various persons at the university and within the radar community, we undertook the task of editing the course notes for formal publication The contents of the book that ensued tend to be practical in nature, since each contributing author is a practicing engineer or scientist and each was selected to write on a topic embraced by his area(s) of expertise Prime examples are Chaps 2, 5, and 10, which were authored by E F Knott, G W Ewell, and N C Currie, respectively Each of these three researchers is recognized in the radar community as an expert in the technical area that his chapter addresses, and each had already authored and published a major book on his subject Several other contributing authors, including Dr Bodnar, Mr Bruder, Mr Corriher, Dr Reedy, Dr Trebits, and Mr Scheer, also have major book publications to their credit Principles of Modern Radar is organized into an introductory chapter and seven parts PART addresses the "Factors External to the Radar," including electromagnetic wave reflectivity and propagation processes and the multipath phenomenon and effects In PART 2, the "Basic Elements of the Radar System" are discussed The basic radar task and objective of "Detection in a Contaminated Environment" of noise and clutter is the subject of PART 3, which includes chapters on noise, clutter, target models, and threshold detection techniques PART is titled "Radar Waveforms and Applications," and these four chapters address special techniques that can result in improved radar performance by introducing waveform conditioning and signal processing trades among the time, frequency, and spatial domains The subjects of tracking in range, angle, and Doppler frequency are presented in PART 5, "Tracking Radar Techniques and Applications." Finally, PART and PART 7-"Target Discrimination and Recognition" and "Radar ECCM", respectively-present important subjects not included in most books on radar Chapters 20 and 21 address polarimetric techniques for target recognition, a very important radar v vi PREFACE topic of the 1980s, and Chap 22 discusses electronic counter countermeasures (ECCM) that should be an integral part of any radar but often are ignored/ overlooked by radar designers and authors of radar books Many people have made contributions to the publication of this book, and we thank them all Among these are those who encouraged us to take on the task of editorship, including all of the contributing authors without whom there would be no book A very special thank-you is extended to Mr Melvin McGee and to his staff, Mr Joseph McKee, and Ms Melanie Luke, for their help in generating and refining the manuscript Also, Ms Shirley Washington is due a special thanks for her support of the short course and the book Finally, we thank Dr H Allen Ecker, formally of Georgia Tech and now with ScientificAtlanta, for he organized and coordinated the first edition of the Principles of Modem Radar short course back in 1969 and started us all on the course that eventually led to the publication of this book JERRY L EAVES K REEDY EDWARD CONTENTS Preface \ v Introduction to Radar, J L Eaves \ PART 1: FACTORS EXTERNAL TO THE RADAR \ 29 EM Waves and the Reflectivity Process, E F Knott \ 31 The Propagation Process, D G Bodnar \ 51 Multipath Phenomena and Effects, H A Corriher \ 72 PART 2: BASIC ELEMENTS OF THE RADAR SYSTEM \ 105 Radar Transmiters, G W Ewell \ 107 Radar Antennas, D G Bodnar \ 148 Radar Receivers, T L Lane \ 182 Radar Indicators and Displays, J A Scheer \ 233 PART 3: DETECTION IN A CONTAMINATED ENVIRONMENT \ 251 10 11 12 Detection in Noise, J D Echard \ 253 Clutter Characteristics and Effects, N C Currie \ 281 Target Models, C R Barrett \ 343 Adaptive Threshold and Automatic Detection Techniques, C R Barrett \ 368 PART 4: RADAR WAVEFORMS AND APPLICATIONS \ 395 13 14 15 16 Continuous Wave Radar, W A Holm \ 397 MTI and Pulsed Doppler Radar, C R Barrett \ 422 Pulse Compression in Radar Systems, M N Cohen \ 465 Synthetic Aperture Radar, R N Trebits \ 502 vii viii CONTENTS PART 5: TRACKING RADAR TECHNIQUES AND APPLICATIONS \ 539 17 Range Tracking, J A Bruder \ 541 18 Angle Tracking, G W Ewell and N T Alexander \ 567 19 Doppler Frequency Tracking, G V Morris \ 598 PART 6: TARGET DISCRIMINATION AND RECOGNITION \ 619 20 Polarimetric Fundamentals and Techniques, W A Holm \ 621 21 Target Recognition Considerations, N F Ezquerra \ 646 PART 7: RADAR ECCM \ 679 22 Radar ECCM Considerations and Techniques, E K Reedy \ 681 INDEX \ 701 INTRODUCTION TO RADAR Jerry L Eaves 1.1 INTRODUCTION The word radar was a code name used by the u.s Navy in 1940, early in World War II, and is an acronym derived from the phrase radio detection and ranging Radar has many uses, and a particular application can involve extremely complex and sophisticated engineering techniques and designs; however, radar is very simple in its most basic form, as shown in Figure 1-1 Its basic objectives are to detect targets of interest and to derive information such as range, angular coordinates, velocity, and reflectivity signature from the detection Electromagnetic (EM) energy generated within the transmitter unit is routed to the antenna via the duplexer, a device that permits both transmission and reception of EM waves with a single antenna The antenna serves as a transducer to couple the EM energy into the atmosphere, where it propagates as an EM wave at the speed of light (approximately X 108 m/s) Generally, the radar antenna will form a beam of EM energy that concentrates the propagating EM wave in a given direction Thus, the beam can be directed to desired angular coordinates by effectively pointing the antenna in that direction through a combination of mechanical and electrical means An object or target located within the antenna beam will intercept a portion of the propagating energy The intercepted energy will then be scattered in various directions from the target and, in general, some of it will be backscattered in the direction of the radar The time delay between transmission by the radar and reception of the signal reflected by a target located at a range R is found from the relationship td = distance velocity 2R c (1-1) where c is the velocity of light This retroreflected energy is called backscatter, as opposed to bistatic scatter or EM scatter in other directions A portion of the backscattered wave is intercepted by the radar antenna, and the collected energy is transduced from the atmosphere or propagation medium into the radar receiver via the transmission lines and the duplexer INTRODUCTION TO RADAR ANTENNA TRANSMITTED EM WAVE S Transmitter s REFLECTED EM WAVE R Figure 1-1 Radar principle and basic system elements The receiver amplifies the weak received signals and translates the information contained at the radio frequency (RF) to video and/or baseband frequencies Signals processed by the receiver are then routed to the radar indicator or display, where the data (range, velocity, amplitude, direction, etc.) that were derived within the receiver (signal processor) are presented to the radar operator In general, the radar derives target information by correlating the received signal with the transmitted signal Target information that can be obtained by radar is given in Table 1-1, along with the correlation process from which it is derived 1.2 BASIC ELEMENTS OF THE RADAR SYSTEM There are four basic elements in any functional radar: a transmitter, an antenna, a receiver, and an indicator The basic configuration is illustrated in Figure Table 1-1 The Derivation of Target Data Target Information Size (radar cross section) Range Angular coordinates Radial velocity (Doppler) Scattering signature Identification Derived by Correlating: Received Signal Strength Time delay Antenna beam position Radio frequency Polarization scattering matrix (PSM) Measured PSM with stored signature Transmitted Signal with with with with Power Time reference Antenna beam reference Frequency reference with EM wave reference for EM wave reference Table 22-2 ECM Versus ECCM Generic ECM A Active Denial Typical ECM Jamming CW Long pulse Spot noise Barrage noise Medium and fast sweep jamming Impulse jamming Short pulse jamming Sidelobe repeaters B Passive Denial Chaff C Active Deception Radar absorbing materials Repeaters False target generator CIl Il:: A Active Denial Jamming (various) B Passive Denial Chaff C Active Deception Radar absorbing materials Repeaters D Passive Deception Range and velocity gate stealers Inverse gain modulation (scan modulation jamming) Angle gate stealers (TWS radars) Decoys ~ ~ t.:l Z ~ u < Il:: E- Chaff Forward chaff ECCM Frequency diversity, frequency agility, fast time constant, gain controls, pulse width discrimination, bistatic radar, triangulation, spread spectrum, low sidelobe antenna, passive correlation All of the above plus integration Frequency diversity, frequency agility, integration, Dicke-Fix, CFAR, bistatic radar Dicke-Fix, CFAR, log FTC, automatic video noise level, local oscillator off, higher ERP, longer time on target Dicke-Fix, CFAR, variable IF bandwidth, integration, pulse compression, frequency agility, guard band blanking Dicke-Fix, CFAR Integration, pulse compression PRF jitter and integration, pulse compression, sidelobe blanking, bistatic radar MTI, Doppler radar, improved resolution (narrow beamwidth, short pulse, pulse compression) log FTC, gain controls, low scan rate on search Higher ERP, longer time on target Complex radar waveform, spread spectrum technique, frequency agility, PRF jitter and integration, sidelobe blanking PRF jitter, frequency agility, lobe sidelobe antenna, diplexing Frequency agility, frequency diversity (diplexing), higher ERP, pulse compression, angle track on jam MTI in angle track, Doppler radar, improved resolution (narrow bandwidth, short pulse, pulse compression) Higher ERP, frequency diversity Complex radar waveform, spread spectrum techniques, frequency agility, PRF jitter and integration PRF jitter, leading edge tracking, acceleration limiting, Doppler/range rate checking Monopulse, lobe on receive only, variable conical scan frequency, CONOPULSE Lobe on receive only Target/decoy trajectory characteristics, multistatic radars, bistatic operations Higher resolution in range and angle, speedgate loop, MTI in angle tracking, leading/trailing edge range tracking ECCM guard gates/coast (By permission, from Johnston, ref 17; © 1978 Horison House) 697 698 22.9 RADAR ECCM SUMMARY Radar counter-countenneasures are included in the radar to reduce radar vulnerability to all types of ECM In general, ECCM works to avoid the jammer frequency, reduce the jammer signal reaching the receiver, prevent receiver saturation, decrease the liS ratio in a noise environment, discriminate between true and false targets, and provide a CFAR To accomplish these objectives, ECCM must be considered during the radar system synthesis and design phase and designed into the radar, not added as an afterthought One of the areas of future emphasis in the development and evaluation of radar ECCM techniques and applications is sure to involve the exploitation of the millimeter wavelength (MMW) frequency spectrum (30-300 MHz) and its inherent advantages from an ECCM standpoint l4 • Indeed, one author has recently tenned millimeter wave radar as "the new ECM/ECCM frontier" 15.16 In particular, MMW radar has unique capabilities to provide narrow beamwidths and high antenna gain, extremely covert operation by proper selection of the operating frequency, the opportunity to incorporate widely differing operating frequencies in dual mode, dual band sensors, and small size and high mobility A more extensive development of MMW radar's inherent ECCM properties is given in References 15 and 16 As this chapter indicates, specific radar ECCM is nonnally required to counter specific ECM Table 22-2 illustrates this principle by identifying ECCM techniques which are effective against specific ECM types 17 22.10 REFERENCES S L Johnston, Radar Electronic Counter-Countermeasures Artech House, Dedham, Mass., 1979 M V Maksimov et aI., Radar Anti-Jamming Techniques, Artech House, Dedham, Mass., 1979 L B Van Brunt, Applied ECM, EW Engineering, Inc., Dunn Loring, Va., 1978 J A Boyd et aI., Electronic Countermeasures, Peninsula Publishing, Los Altos, Calif., 1978 H F Eustace, The International Countermeasures Handbook, 1979-1980, EW Communications, Palo Alto, Calif., 1980 P Tsipouras, et aI., "ECM Technique Generation," Microwave Journal, vol 27, no 9, September 1984, pp 38-74 U.S Army Field Manual, FM 100-5, Operations, Headquarters, Department of the Army, July 1976 S L Johnston, "ECCM Improvement Factors (ElF)," Electronic Waifare, vol 6, no 3, May-June, 1974, pp 41-45 P Klass, "GAO Study Expands AWACS Data," Aviation Week and Space Technology, September 15, 1975, pp 47-51 10 P R Dax, "Noise Jamming of Long Range Search Radars," Microwaves, vol 14, no 9, September 1975, pp 52-60 11 M A Johnson and D C Stoner, "ECCM From the Radar Designer's Viewpoint," Microwave Journal, vol 21, no 3, March 1978, pp 59-63 RADAR ECCM CONSIDERATIONS AND TECHNIQUES 699 12 J V Difranco and C Kaiteris, "Radar Performance Review in Clear and Jamming Environments," IEEE Transactions on Aerospace and Electronic Systems, vol AES-17, no 5, September 1981, pp 701-710 13 S L Johnston, "Hostile ECCM/ESM-Potential Achilles Heel for U.S EW," Journal of the Electronic Defense, vol 7, no 6, June 1984, pp 41-48 14 E K Reedy, "Millimeter Radar, Fundamentals and Applications," Military Electronics and Countermeasures, vol 6, no 8, August 1980, pp 62-65 15 S L Johnston, "MM-Wave Radar Challenges and Benefits EW Applications," Microwave Systems News and Communications Technology, vol 16, no 6, June 1986, pp 95-110 16 S L Johnston, "MM-Wave Radar: The New ECM/ECCM Frontier," Proceedings of Military Microwaves Conference (MM-84), London, October 1984, pp 424-435 17 S L Johnston, "Guided Missile System ECM/ECCM," Microwave Journal, vol 21, no 9, September 1978, pp 20-24 INDEX "A" scope display, 233, 234, 448 Accuracy angle measurement, 387, 584 frequency measurement, 601 range measurement, 561 Active arrays, 172 AFC (see Automatic frequency control) AGC (see Automatic gain control) Agility, frequency, 442 Air-to-ground applications, 399, 502, 560 Alpha-beta (a-{3) filter, 584 tracker, 609 Altimeter, 542, 551 Altitude effect on sidelobe clutter, 420 return, 426 Ambiguities consideration in choice of PRF, 419, 519, 524 Doppler, 420, 425, 433, 494 range, 420, 430, 494 resolution, Doppler, 430, 431 Ambiguity function, 425, 434, 438 Amplifier crossed field, 110, 116, 117, 118, 119, 120 extended interaction, 127, 132 IF (Intermediate Frequency), 208, 209, 218,219,262,403,404,406 IMPATT, 110 klystron, 110, 121, 122, 123 low noise preamplifier, 220, 221, 222 traveling wave tube, 110, 123, 124, 125, 126, 128, 129 Amplitude-comparison monopulse, 569 Amplitude scintillation, 586 Analog filters, 445, 457 signal processing, 513 AN/FPS-85,475 AN/FPS-115,475 Angle gate, 582 measurement, 387 noise, 586 resolution, 504 scintillation, 586 tracking, 567 tracking error, 584 tracking error measurement, 386 tracking filter, 584 AN nomenclature system, 23, 24 Antenna, 3, 9, 148 aperture, array, 172, 504 (see also Array) beam, 152 blockage, 159 effective area, 9, 11 electronic counter-countermeasures (ECCM), 686, 691 gain, 9, 150 radiation explained, 148 radiation pattern, 148 search scan, 433 sidelobes, 152, 688 size, limitations on, 151 tolerance effects, 162, 180 tracking control, 567 tracking feeds, 568, 571 Antiradiation missile (ARM), 681, 692 Aperture definition of, 151 effective area of (Ae), 151, 522 efficiency (11), 149 Area of radar cell, beam limited, 286 pulse limited, 286 ARM (see Antiradiation missile) 701 702 INDEX Array antennas, 172 active, 172 bandwidth, 178 feed networks, 174 linear, 172 planar, 174, 574 synthetic, 505 Artificial intelligence, 652, 654, 670, 671, 673, 674 Atmospheric attenuation, 66 Autocorrelation, 260 function, 416, 417 Automatic frequency control, 438 Automatic gain control, 188 Automatic tracking, 541, 567 Average power, 398, 408 Azimuth compression, 505, 524 "B" scope, 235, 236 Back heating, 113 Backscatter, atmospheric, 51 target, 343 Bandwidth, 189, 194, 196, 197, 198,407, 408,410,411 filter, 197, 198, 386, 407 Phased array, 177 pulsed signal, 197, 198 time-bandwidth product, 466, 511 Barker phase codes, 480 Beam antenna, 152 area, 285 Beamwidth, 504 circular aperture, 157 definition of, 153 effect on tracking error, 584 focused synthetic array, 507 rectangular aperture, 155 unfocused synthetic array, 507 Beaufort sea chart, 323 Bessel function, 413, 414 Binary phase coding, 416, 478 Bistatic radar, 86 Bistatic scatter, Blind zones Doppler, 399 Blip-scan ratio, 99 Boltzmann constant, 521 Brightness, 242 Burnthrough, 687, 692 Carrier frequency, 402 Cassegrain antenna, 169, 570 Cassegrain twist reflector, 573 Cathode, 237 Cathode ray tube (CRT), 233, 237 CFA (see Crossed field amplifier) CFAR (see Constant false alarm rate) Chaff,594 Chirp, 469 Circular polarization, 490 Classification, 647, 666 CloSing rate, 399 Clustering, 659, 664, 666 Clutter, 621, 638, 639, 640, 641 amplitude return, 289, 423, 426, 432 canceller, 444, 451 definition, 281 discrimination (see Target discrimination) effect of ambiguities on, 423 frequency dependence, 291 mainlobe, 426, 458 models, 334 rejection, 451, 453 sidelobe, 423 temporal properties, 292 Clutter referenced MTI, 449, 453 Coherent detection, 223, 224, 226, 227, 228 Coherent interference, 81 Coherent on receive (COR), 224, 225, 449 reference oscillator, 443 Coherent sidelobe canceller (CSLC), 690 Combined Barker codes, 481 Complementary phase codes, 486 Conical scan tracking, 568 antenna feeds, 568 Conical-scan-on-receive-only (COSRO), 576 Constant false alarm rate (CFAR), 354, 362, 368,621,693 determining noise level for, 349, 370 distribution free, 369, 373 multicell, 362, 370, 387 Constants (physical), 397 Continuous Wave (CW) radars, 397, 419 altimeters, 399 comparison with pulsed radars, 398 definition of, 398 Doppler tracking, 602 frequency-modulated, 414 multiple-frequency, 414 phase modulated, 416 proximity fuzes, 399 INDEX radar range equation, 407 range measurement in, 398,409,430 separation of transmitted and received signals in, 399,403,413 simple systems, 402 spectrum, 404 Correlation process (TWS), 385 Cosine-squared weighting, 492 COSRO (see conical-scan-on-receive-only) Covariance matrix, 638 Crossed field amplifier (CFA), 110, 116 circular format, 117 debunching in, 117 linear format, 117 modulator interaction, 119 operating characteristics, 118 self-pulsing, 119 types, 116, 117 typical characteristics, 120 Cross section, radar (a), 343 effective (aeff), 86, 101 effect on detection range, 352 effect on tracking error, 584 fluctuations in, 343 CSLC (see Coherent sidelobe canceller) Cumulative probability of detection (see Probability) Decay time, 238 Decorrelation time definition, 300 foliage, 321 rain, 302 Delay-line clutter canceller, 446, 452 Delta function, 404, 405 Density matrix, 638 Detection (target), 183, 184, 253, 254, 648 automatic, 279, 349, 364, 368 cathode ray tube (CRT), 278 coherent, 254, 268, 269 correlation, 253, 265 criteria, 266 curves, 270, 274, 276, 277 envelope, 268 zero-crossing, 268 errors, 266 human operator, 278 in-phase and quadrature phase (I&Q), 254 laws, 268, 269 linear-law, 269, 270 703 logarithmic, 269 Neyman-Pearson, 267 probability (see probability), process, 348, 368 range definition of, effect of postdetection integration, 349, 352 equations for, 349 factors governing, 96 threshold (see threshold detector), 349, 368, 387 square-law, 269 synchronous, 254, 268, 269 Detectors, 185, 186, 187,213,214,349,370 DFT (see Fourier transform) Dicke fix, 694 Diffraction, 52 Digital filter advantages, 447 bank,446 coefficients, 447, 455 forming (general), 445 multipulse canceller, 442, 456 nonrecursive, 455 recursive, 455 Digital scan conversion, 246 Digital signal processing, 404, 647 (see also Fourier transform) Doppler filter bank, 404, 446 synthetic array radar, 516 Digital signal processors basic functions, 368 evolution, 647 Directivity angle measurement, 174 antenna, 150 Discrete Fourier Transform (see Fourier transform) Discriminants depolarization, 639 matrix, 638, 640, 641 odd/even bounce, 639 polarization ratio, 639 pseudocoherent detection, 639 scalar, 638 vector, 638, 639, 640 Discriminant (in tracking loops), angle (see error slope) range, 544, 549 Discrimination (target), 648 704 INDEX Display, 233 controls, 241 formats, 233 radar, 233 system, 239 tactical situation, 234 timing, 241 Distribution free CF AR (see Constant false alarm rate) Divergence factor, 76, 77 Dolph-Chebyshev weighting, 492 Doppler ambiguities, 494 causes, 421 effect of PRF on, 419 in ground return, 423, 434 resolution of, 430 effect, 399 equation, 332 filters, 444, 446, 454, 456, 457, 499 frequency of ground return, 421 isodops, 423 profile, 430 shift distinguishing direction of, 405, 406 explanation of, 399 spectra of ground return, 430 tracking loop, 601 Douglas sea state, 323 Duplexer, 187, 198, 199,200,398 Duty factor, 398 Dynamic range, 196,203,204,206,219,220 "E" scope, 235, 237 ECCM (see Electronic counter-countermeasures) ECM (see Electronic countermeasures) Effective earth model, 57 Effective radiated power, 691 Electrical noise, 253, 403 Electromagnetic (EM) waves, 31, 397, 398, 414,622, 634 circular polarized, 34 cylindrical wave, 34 elliptically polarized, 34 hierarchy of scattering shapes, 42, 43 linearly polarized, 34 plane wave, 33 spherical wave, 34 wave equation, 42 Electron beam, 237 Electron gun, 237 Electronic beam steering (active arrays), 172 Electronic counter-countermeasures (ECCM), 468, 594, 681 Electronic countermeasures (ECM), 594, 682, 697 angle deception, 595 barrage noise, 595 chaff, 594 spot noise, 594 swept noise, 595 Electronic intelligence (ELINT), 681 Electronic scanning, 172, 687 Electronic support measures (ESM), 682, 692 Electronic warfare (EW), 681, 682 Electrostatic deflection, 237 Elevation coverage (in multipath), 100 ELINT (see Electronic intelligence) EM waves (see Electromagnetic waves) Emission control (EMCON), 695 Ergodic, 260 ERP (see Effective radiated power) Error slope, 571 ESM (see Electronic support measures) Eta (1/) (radar cross section per unit volume), 284 EW (see Electronic warfare) Extended interaction devices, 127, 132 False alarms, 254, 266 False-alarm rate (see Probability), Far field, 148 Fast Fourier transform (FFT) (see Fourier transform) Feature (target), 649, 662 dimensionality, 655, 659 extraction, 655, 656, 663 space, 659, 664, 665 vector, 658, 667 Feature space, 642, 643 FTT (see Fourier transform) Field strength, 85, 91 Filter alpha-beta, 584 analog, 445, 457 bandwidth, 197, 198 Chirp (pulse compression), 477 delay line canceller, 446 digital, 442, 445, 446, 447, 455, 456 Doppler, 444, 446, 454, 456, 499 matched, 197, 198,385,407,467 INDEX Flat earth approximation, 75 Fluctuating (see target) Focused synthetic array, 507 azimuth resolution, 508 Fog, attenuation by, 69 Fourier Transform, 405, 406 discrete (DFT), 457, 499 fast (FFT), 404, 656 for pulse modulated carrier, 433 Frank codes, 487 Frequency agility, 442, 692 bands ECM, 23, 26 radar, 23, 26 diversity, 692 image, 194, 195 influence on radar performance, 67 measurement accuracy, 601 modulation, CW 409 translation, 402, 606 Frequency modulated continuous wave (FMCW) radar, 409 Frequency modulation (FM) ranging basic principle, 430 spreading of clutter, 431 Fresnel reflection coefficient, 76 Fast time constant (FTC), 694 Gain antenna, 151 definition, 150 for circular aperture, 158 for rectangular aperture, 156 Gating, Track-While-Scan, 579 Gaussian distribution, 293 GH filter, 584 Glint, 586 Golay codes, 487 Grating lobes, 174 Ground mapping (see Mapping), 560 SAR display of, 526 Gyratrons, 132, 133 operating conditions, 134 Hamming weighting, 492 Harmonics, 202, 203, 204, 206, 413 705 Hartree voltage, 111 Height-gain curve, 85 High PRF operation definition of, 420 Doppler profile, 430, 439 Doppler tracking, 605 range measurement, 430 High resolution ground mapping, applications, 526 Horizontal sweep, deflection, 240 Huynen decomposition, 637, 638 Hybrid tracking radars, 576 I&Q (see In-phase and quadrature-phase) Identification (target), 647, 648 Identification friend or foe (IFF), frequencies, 194, 195 IF (see Intermediate frequency) Improvement factor, 451 Indicator, 23 In-phase and quadrature-phase (I&Q) components, 189,214,271,254,405,406, 606 Integrated sidelobe levels, 467 Integration, 408 binary, 278 coherent, 272, 273, 274, 275 noncoherent, 273, 274, 275 postdetection, 274, 349, 352, 368 predetection, 274 pulse, 272 time influence on SNR, 273 limitations on, 368 trade-offs in ranging, 559 Interference pattern, 84 Intermediate frequency (IF), 188, 218 explanation of, 403 gain, 243 translation to, 197,201,202,203,403,404 value used for analog Doppler filtering, 197, 198 Inverse synthetic aperture radar (ISAR) (see synthetic aperture radar) Ionospheric propagation, 63 Intrapulse modulation, 467, 478 (see also Pulse compression) Intrapulse polarization agile radar (IPAR), 490 Isodop, 420 706 INDEX Jammer equation, 686 Jamming, 594, 686 barrage noise, 595 cross polarization, 596 spot noise, 594 swept noise, 595 Jamming-to-signal (J/S) ratio, 686 Jones calculus, 627 Kalman Filter, 609 Klystron, 110, 121 characteristics, 123 focusing, 122 general characteristics, 121 gridded, 122 noise in, 123 operating characteristics, 122 principal parts, 121 sensitivities, 123 Leading edge range tracker, 550 Light, velocity of, 397 Light Emitting Diode (LED), 243 Linear frequency modulation, 469 Local oscillator (LO), 216, 217, 218 Loss, 408 antenna (gain), 149, 151, 156, 158, 160, 161, 178 atmospheric, 66 beamshape, 385 constant false alarm rate (CFAR), 354, 362 distribution free, 377, 383 nonparametric processes, 377, 383 Low pulse repetition frequency (PRF) operation definition of, 420 Doppler profile, 430, 439 detection threshold setting, 349, 364 (see also Doppler filters) Low probability of intercept radar (LPIR), 468 Magnetic deflection, 237 Magnetrons, 110 cavity, 110 characteristics, 116 coaxial, 110 continuous wave (CW), 115 frequency agile, 114 heater schedule, 114 moding, 111 principal parts, 11 0, 111 pulling, 114 pushing, 114 rising sun, 110, 116 Mainlobe clutter rejection, 445 low pulse repetition frequency (PRF), 451 spectrum, 420, 458 effects of ambiguities on, 423 Mapping geographic/geological applications, 526 range resolution, 560 strip mapping, 526 Master oscillator power amplifier (MOPA), 107 Matched filter, 197, 198,253,262,263,264, 385, 407, 467, 495 (see also Filter) Maximal length binary code, 417, 418 Maximum detection range, 15 multipath effects on, 96 single pulse, 352 single scan, 352 statistical nature of, 352 Maximum length sequences, 483 Medium PRF operation definition of, 420 Doppler, profile, 430, 439 range, profile, 430 Microwave resolver, 576 Millimeter wave (MMW), 698 Minimum detectable signal (Sm'n)' 182, 183, 255 Mismatch filtering, 492 Mixer, 186,201,402,403 Modulation phase and frequency modulation, 409, 416, 465 pulse compression, binary phase, 478 linear FM (chirp), 469 polyphase, 486 stepped frequency, 475 ranging (FM), 430 Modulators floating deck, 138, 139 hard tube, 138, 139 important factors, 137 line-type, 139 PFN,140 solid-state, 141 stability, 142 type comparisons, 143, 144 Molecular absorption, 66 INDEX Monopulse, 567 amplitude comparison, 569 antenna feeds, 571 phase comparison, 574 single channel, 576 two channel, 579 Moving Target Indication (MTI), 419, 444, 449,621,693 clutter referenced, 449 coherent-on-receive, 449 externally coherent, 449 improvement factor, 451 phase sensitive, 449 Mueller calculus, 627 Mueller matrix, 636, 637, 638, 641, 643 Huynen decomposition, 637, 638 in terms of RCS, 636 Multimode Doppler radar, 468 Multipath propagation, 72, 591 Multiple frequency CW radar, 414 Natural decomposition, 638 Near field, 148 Neyman-Pearson, 254, 267 Noise, 254, 256 atmospheric, 253 bandwidth, 189, 194, 253 electrical, 184, 190, 195, 196, 197,403 factor, 12 figure (Fn), 12, 190, 191, 192 double sideband noise figure (DSBNF), 194, 195 single sideband noise figure (SSBNF), 194, 195 flicker, 403 jamming, 686 mixer, 192, 193 receiver, 191, 192, 193, 194, 195 temperature, 191 thermal, 184, 189 white, 261, 262 Nonfluctuating (see target) Nonparametric CFAR, 369, 373 Nonuniform field (in multi path), 91 Nutation, 568 Offset PPI, 234 Optical SAR processor, 513 Optimal mismatch filter, 493 Over the horizon (OTH) radars, 63 Parabolic antenna, 165 707 Path length difference (., 387 detection (Pd), 20, 269, 275, 348, 352, 374, 377 factors affecting, 21 density function, 18, 256, 257 false alarm (Pfa), 20, 275, 348, 349 definition, 20 single pulse, 20 histogram, 18 Propagation, 51 anomalous, 62 ducting, 63 effective earth, 57 ionospheric, 63 standard, 58 Proximity fuze, 399 Pseudo-Brewster angle, 77 Pseudo conical scan, 576 Pseudorandom binary codes, 417, 418 Pseudorandom sequences, 483 Pulse compression, 226, 465, 693 binary phase coding, 478 combined Barker codes, 481 complementary phase codes, 486 limitations, 468 sidelobes, 466, 480, 484, 492, 496 chirp (linear frequency modulation), 469, 477 pulse compression ratio, 473 range sidelobes, 472 sidelobe reduction, 492 time-bandwidth product, 466 polyphase coding, 487 Pulse delay ranging, 541 basic technique, 541 display, 233, 234 maximum unambiguous range, Ru , 519, 525 Pulse repetition frequency (PRF) discrimination, 694 high,419 low, 419 medium, 419 relation to Doppler ambiguities, 423 Doppler profile, 423 range ambiguities, 430, 434 range profile, 423 selection for synthetic aperture radar (SAR), 519, 524 Pulsed Doppler, 419 Pulsers (see Modulators) Pulse width discrimination, 694, 695 Pulling figure, 113 Pushing figure, 113 Radar, 1,2 antenna, basic elements, antenna, indicator, receiver, transmitter, blinking, 696 continuous wave (CW), 397 decoys, 696 definition of, detection, 16 historical developments, history of, indicator, nomenclature, 23, 25 police, 408 receiver, 2, some major functions, 22 synthetic aperture (SAR), 502 tracking, 567 transmitter, Radar cross section (RCS), 9, 38 clutter, 283 commercial jetliner, 47 INDEX definition, 9, 39 equivalent flat plate area, geometric, in terms of polarization scattering matrix, 628 large ship, 48 null, 631 optimum, 629 per unit area, 284 per unit volume, 284 scattering centers, 47 scintillation, 47 Radar Data Processor (RDP), 373 Radar equation,S, 407, 408 forms of, 70, 441 simple form, II single pulse, 182 Radiation pattern, 152 Radiators (antenna) array elements, 172 active array, 172 linear array, 172 planar array, 174 Radio frequency, influence on performance, 67 Random process, 253, 255, 257, 260 Range accuracy, 561 ambiguity, 419 detection, probabilities of, 352, 373 discriminant, 544, 549 dynamic (see Dynamic range) gate/gating, 545, 548, 550, 555 analog system, 446, 544 digital system, 552 Doppler tracking, 607 gate pull off (RGPO), 595 measurement, 398, 541 resolution, 226, 227, 228, 560 frequency modulated continuous wave (FMCW), 410, 411 ground mapping, 560 improvement through pulse compression, 465 sidelobes, 152,467,479 sweep, 235 tracking, 541 analog, 544 digital, 552 Range rate measurement, 544, 549, 552 concept, 559 Doppler method, 399 velocity tracking loop, 607 709 Raster scan, 244 Rayleigh distribution, 292 Rayleigh roughness criteria, 77, 289 Ray paths (in multipath), 78 RCS (see Radar cross section) Receiver, 182 correlation, 265 electronic counter-countermeasures (ECCM),693 logarithmic, 269 noise, 403 protection device, 198, 199, 200, 201, 202 radar example of, 185, 186, 187, 188,223, 224, 225, 226, 227, 228, 229 role of, 183, 184 simple, 184, 185, 186 superheterodyne, 185, 186, 187,403 Recognition, 646, 647, 648, 671, 673 Reflection, 52 Reflectivity ground, 76 target, 343, 345 Reflectivity process, 31, 35 boundary conditions, 35 geometric optics, 36 geometric theory of diffraction, 37 physical optics, 36, 40 Refraction, 54 Resolution along-track (see cross range) cross range, 504, 511, 523 distance (mapping), synthetic aperture radar (SAR), focused, 507 synthetic aperture radar (SAR), unfocused,507 range, 560 frequency modulated continuous wave (FMCW), 410, 411 ground mapping, 560 improvement through pulse compression, 465 Resolver, 576 Response, impulse, 264 Return power vs range, 92 RGPO (see Range gate pull off) Rician distribution, 292 Robustness, 655, 656, 672 Roughness factor, 76, 77 SAR (see Synthetic aperture radar) 710 INDEX Scan, antenna electronic, 172 tracking, 567 track-while-scan, 562, 567 Scan conversion, 246 digital, 247 optical, 246, 247 scan-on-receive-only (SORO), 596 scan with compensation (SWC), 576 Scatter/scattering, backscattering atmospheric, 295 ground, from, 303 amplitude, 303 depression angle effect on, 290 spatial, 312 temporal, 316 scattering matrix, definition, 288 sea, from, 321 Scattering length, 91 Scintillation concept, 343 effect on detection range, 352 tracking error due to, 586 Scope displays formats ("A," "B," etc.), 233,448 scan converter, 246 Screening range, 686, 693, 694 SEASAT, 527, 530 Sea state, 323 Self-screening jammer (SSJ), 688 Sensitivity Time Control (STC), 188, 196, 243 Sequential lobing, 567 Shift registers, 417, 418 Sidelobes antenna, 152 range, 467, 478 reduction of, antenna, 154 Sidelobe blanker, 690 Sidelobe blanking, 688 Sidelobe canceller, 690 Sidelobe cancelling, 688 Sidelobe clutter, 421 amplitude return, 425 general characteristics, 421 Sigma zero «(To), definition, 294 Signal minimum detectable (Sm;n), 182, 183, 193, 196 spectral width, 406, 407 Signal processing, synthetic aperture radar (SAR),512 Signal processor digital, 369 digital (synthetic aperture radar), 516 electronic counter-countermeasures (ECCM),693 optical (SAR), 513 Signal-to-Noise Ratio (SNR), 12, 183, 193, 259,275,407,408 improvement though integration, 228, 275 input, 12 output, 12, 14, 15 required for detection, 352 reduced through post detection integration (PDI), 352 vs detection probability, 352 single-channel monopulse, 576 synthetic aperture radar (SAR), clutter, 522 target, 521 Signature (target), 653 Sin xix shape, 407 antenna pattern, 155 chirp, compressed pulse, 470 Site selection for electronic counter-countermeasures (ECCM), 696 Situation display, 234 Solid state transmitters, 133 SORO (see Scan-on-receive-only), Spectral line width, 407 Spectrum component parts internal motion, 420 plot formation, 420 scanning modulation, 420 stability, 421 frequency modulated continuous wave (FMCW),413 Speed of light, 54, 397 Split gate range tracker, 545 Spread spectrum electronic counter-countermeasures (ECCM), 692 Squint mode (synthetic aperture radar), 523 Stable local oscillator (STALO), 445 Stand-off jammer (SOJ), 688, 693 Stepped frequency technique, 226, 227, 228 Stokes reflection matrix (see Mueller matrix) Stokes vector, 634, 635, 636 Stretch radar, comparison with synthetic aperture radar (SAR) processing, 512 Strip mapping, 526, 560 SWC (see Scan With Compensation), INDEX Synchronous (I1Q) detector, 405, 406 operation of, 254, 405, 406 use in CW radars, 405, 406 Synthetic aperture radar, 502 advantages of, 504 applications, 526 aperture time, 510 array length, 506 basic concept, 505 compression, azimuth, 514, 517 Doppler processing, Doppler frequency vs, angle, 421 focused array phase correction, 507 resolution, 508 signal processing, 514, 516 grating lobes, 174 map quality, shadows, 527 modes ISAR,528 spotlight, 526 squint, 523 strip map, 526 motion compensation, 516 noise, effects of, 521 operational modes, spotlighting, 526 squint, 523 strip mapping, 526 phase correction, focusing, 507 correction, motion compensation, 516 errors, uncompensated, 518, 523 PRF selection, 419, 519, 524 resolution focused array, 507 unfocused array, 507 sidelobes reduction of, 154 weighting, 512 signal processing, Doppler (see Doppler filtering) unfocused array, 507 limitations of, 507 maximum effective length, 508 minimum resolution distance, 508 Tapered illumination, 154 Target, 254 detection, 621 discrimination, 621, 638, 639, 640, 641 discriminants (see Discriminants) 711 enhancement, 451 identification, 621 information, derivation of, models, 343, 345, 362 nonfiuctuating, 258, 269 odd/even bounce characteristics, 629 optimum RCS of, 629 orientation of, 629 polarizability of, 629 recognition of, 621, 641, 642, 643 symmetry of, 629 track, 567 vertically extensive, 86, 92 Target identification/classification, 647, 648, 666 noncooperative techniques, 343 recognition, 646, 647, 648, 671, 673 Terrain following, 237 Threshold detector, determining noise level for, 368 general approach, 348, 364 Thumbtack ambiguity, 495 Time-bandwidth product, 511 Time-on-target (Td ), 406 Time relationships (in muitipath), 79 Tracking angle, 569 basic concepts, 567 conical scan, 568 filter, 584 hybrid, 576 lobing, sequential, 567 monopulse, 569 multipath effects on, 100 sequential lobing, 567 track-while-scan (TWS), 579 point tracking, 567 range, 541 analog systems, 544 digital systems, 552 concepts, 552, 556 discriminant, 553, 557 filter, 554 gating, 555, 556 loop, 553, 557 single target track (STT), 565 analog systems, 544 digital systems, 552 track-while-scan (TWS), 562 concept, 562, 579 correlation, 563 filtering, 563, 584 712 INDEX Tracking (Cont.) gating, 581 track initiation/deletion, 563 velocity (Doppler) airborne, 614 CW,602 general, 598 high PRF, 605 loop, 604 range gated, 607 Tracking errors due to noise, 561, 584 Trailing edge range tracker, 552 Transform, Fourier, 405, 406 applied to pulse-modulated carrier, 433 fast (FFT), 404 use in synthetic aperture radar, 517 Transition range, 90 Transmitter, 107 characteristics, 108 comparison of types, 135 electronic counter-countermeasures (ECCM),691 Traveling wave phenomenon, 48 Traveling wave tube (TWT), 110, characteristics, 126, 128, 129 general characteristics, 123 interaction circuits, 125 principal parts, 124 sensitivities, 126 Twist-reflector antenna, 573 Two-channel monopulse, 579 TWS (see Track-While Scan), 562 TWT (see Traveling wave tube) Twystron, 127 commercially available, 131 frequency characteristics, 130 Unfocused synthetic array description, 507 limitations, 507 Velocity (Doppler), 399 discriminant, 438 gate pull off (VGPO), 595 tracking loop, 604 Vertical interference lobes, 84, 85 Vertically extensive targets, 86, 92 Vertical sweep, deflection, 240 Velocity gate pull off (VGPO), 595 Video, 241 gain, 242 Volume or radar cell, 287 Waveform coding, electronic counter-countermeasures (ECCM), 693 Waveform parameters, 397, 398 Waveform, pulsed categories of (PRF), 419 characteristics of, 420 choice of, 420, 498 frequency modulated, 468 phase coded, 478 Wave height, 321 Weather attenuation by, 68 radars, synthetic aperture radar (SAR) 532 Weibull distribution, 293 Weighting amplitude, 154, 385 Welti codes, 487 Yoke, 238 ... ONLY (FABRICATED DATA, NOT TO SCALE) N = 100 SAMPLES Ll V = 0.1 VOLTS L ALL V L 'llyiLl V LlV=1 N 'll =1 ALL V N 'lly/Ll V N 0.2 0.6 0.4 V Figure 1-6 Probability histogram for measurements described.. .PRINCIPLES OF MODERN RADAR PRINCIPLES OF MODERN RADAR Edited by Jerry L Eaves and Edward K Reedy CHAPMAN & HALL I ® J:f International Thomson Publishing New York' Albany' Bonn •... first edition of the Principles of Modem Radar short course back in 1969 and started us all on the course that eventually led to the publication of this book JERRY L EAVES K REEDY EDWARD CONTENTS