Table Of ContentFundamental Principles of Radar
Fundamental Principles of Radar
Habibur Rahman
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2019 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Printed on acid-free paper
International Standard Book Number-13: 978-1-138-38779-9 (Hardback)
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made
to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all
materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all
material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not
been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any
future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or uti-
lized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopy-
ing, microfilming, and recording, or in any information storage or retrieval system, without written permission from the
publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://
www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923,
978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organi-
zations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for iden-
tification and explanation without intent to infringe.
Library of Congress Cataloging‑in‑Publication Data
Names: Rahman, Habib, author.
Title: Fundamental principles of radar / authored by Habib Rahman.
Description: Boca Raton : Taylor & Francis, [2019] | Includes bibliographical references.
Identifiers: LCCN 2019001998| ISBN 9781138387799 (hardback) | ISBN 9780429279478 (ebook)
Subjects: LCSH: Radar.
Classification: LCC TK6575 .R324 2019 | DDC 621.3848—dc23
LC record available at https://lccn.loc.gov/2019001998
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
eResource material is available for this title at https://www.crcpress.com/9781138387799.
Dedication
To our grandson ZADE
for the joy he brings to our lives, and
to our son TANVIR
who is a beacon to reconciliation and social justice.
Contents
Preface ...........................................................................................................................................xiii
Author ...........................................................................................................................................xvii
Chapter 1 Introduction ..................................................................................................................1
1.1 Historical Notes .................................................................................................1
1.2 Elementary Electromagnetic Waves ..................................................................3
1.3 Radar Principles ................................................................................................3
1.4 Basic Radar Block Diagram and Operation ......................................................4
1.5 Basic Elements of Radar System .......................................................................5
1.6 Types of Radar Systems ....................................................................................7
1.6.1 Primary and Secondary Radar .............................................................7
1.6.2 Monostatic, Bistatic, and MIMO Radars .............................................7
1.6.3 Search Radars .......................................................................................8
1.6.4 Tracking Radars ...................................................................................8
1.6.5 Classification by Frequency Band ........................................................8
1.6.6 Classification by Waveforms and Pulse Rates .....................................8
1.6.7 Classification by Specific Applications ................................................9
Notes and References .................................................................................................10
Chapter 2 Radar Fundamentals ..................................................................................................11
2.1 Introduction .....................................................................................................11
2.2 Detection..........................................................................................................11
2.3 Range ...............................................................................................................11
2.3.1 Range Ambiguity ...............................................................................12
2.3.2 Range Resolution ................................................................................13
2.4 Velocity Measurement .....................................................................................14
2.5 Target Location Measurement .........................................................................18
2.6 Signature Reflectivity and Imaging .................................................................18
Problems .....................................................................................................................19
Chapter 3 Radar Equations .........................................................................................................21
3.1 The Radar Equations: An Introduction ...........................................................21
3.2 The Pulse Radar Equation ...............................................................................25
3.2.1 SNR in Low PRF Radars ...................................................................25
3.2.2 SNR in High PRF Radars ..................................................................27
3.3 The Search Radar Equation .............................................................................28
3.4 The Tracking Radar Equation .........................................................................30
3.5 The Bistatic Radar Equation ...........................................................................30
3.6 The Radar Equation with Pulse Compression .................................................32
3.7 Radar Equation with Jamming ........................................................................33
3.7.1 Self-Screening Jamming (SSJ) ...........................................................34
3.7.2 Stand-Off Jamming (SOJ) ..................................................................36
3.8 The Beacon Radar Equation ............................................................................37
Problems .....................................................................................................................40
vii
viii Contents
Chapter 4 Targets and Interference .............................................................................................43
4.1 Introduction .....................................................................................................43
4.2 Radar Cross Section (RCS) .............................................................................43
4.2.1 RCS of Sphere ....................................................................................44
4.2.2 RCS of Cylinder .................................................................................47
4.2.3 RCS of Planar Surfaces ......................................................................47
4.2.4 RCS of Corner Reflectors ...................................................................48
4.2.5 RCS of a Dipole ..................................................................................49
4.2.6 RCS of Complex Objects ....................................................................50
4.3 RCS Fluctuations and Statistical Models ........................................................51
4.4 Radar Clutter ...................................................................................................53
4.4.1 Surface Clutter ...................................................................................54
4.4.2 Volume Clutter ...................................................................................57
4.4.3 Point (Discrete) Clutters .....................................................................61
4.5 Clutter Statistical Distributions .......................................................................62
4.6 Clutter Spectrum .............................................................................................64
4.7 Radar Receiver Noise ......................................................................................64
4.7.1 Noise Factor and Effective Temperature of a System ........................66
4.7.2 Noise Temperature of Absorptive Network........................................68
4.7.3 Overall Effective Temperature of a Composite System .....................69
4.8 System Losses ..................................................................................................70
4.8.1 Design Losses .....................................................................................70
4.8.2 Operational Losses .............................................................................71
4.8.3 Propagation Losses .............................................................................72
Problems .....................................................................................................................73
References ..................................................................................................................73
Chapter 5 Propagation of Radar Waves ......................................................................................75
5.1 Introduction .....................................................................................................75
5.2 Reflection Effects due to Multipath Phenomena .............................................75
5.2.1 Reflection from a Plane Flat Earth .....................................................75
5.2.2 Reflection from a Smooth Spherical Earth ........................................80
5.3 Refraction of EM Waves..................................................................................84
5.3.1 Four-Thirds Earth Model ...................................................................85
5.3.2 Anomalous Propagation .....................................................................86
5.4 Diffraction of EM Wave ..................................................................................88
5.5 Attenuation by Atmospheric Gases .................................................................89
5.6 Ionospheric Attenuation ..................................................................................92
Problems .....................................................................................................................93
References ..................................................................................................................94
Chapter 6 Continuous Wave (CW) Radars .................................................................................97
6.1 Introduction .....................................................................................................97
6.2 Unmodulated Continuous Wave (CW) Radar .................................................98
6.2.1 Homodyne Receiver ...........................................................................98
6.2.2 Doppler Shift and Range Rate............................................................98
6.2.3 Superheterodyne Receiver ................................................................100
6.2.4 Sign of the Radial Velocity .............................................................101
Contents ix
6.3 Frequency Modulated CW Radars ................................................................102
6.3.1 Linear Frequency-Modulated CW Radars .......................................102
6.3.2 Sinusoidal Frequency-Modulated CW Radars .................................105
6.4 Multiple-Frequency CW Radar .....................................................................107
6.5 Phase-Modulated CW Radar .........................................................................108
Problems ...................................................................................................................110
References ................................................................................................................111
Chapter 7 MTI and Pulse Doppler Radars ...............................................................................113
7.1 Introduction ...................................................................................................113
7.2 Description of Operation ...............................................................................113
7.3 Single Delay-Line Canceler ...........................................................................117
7.4 Double Delay-Line Canceler .........................................................................119
7.5 MTI Recursive Filter .....................................................................................120
7.6 MTI Nonrecursive Filter ...............................................................................121
7.7 Staggered Pulse Repetition Frequencies .......................................................122
7.8 Pulse Doppler Radar......................................................................................124
7.9 Range and Doppler Ambiguities ...................................................................125
7.9.1 Resolution of Range Ambiguity .......................................................125
7.9.2 Resolution of Doppler Ambiguity ....................................................127
Problems ...................................................................................................................129
References ................................................................................................................129
Chapter 8 Pulse Compression Radar ........................................................................................131
8.1 Introduction ...................................................................................................131
8.2 The Matched Filter ........................................................................................131
8.3 The Radar Ambiguity Function ....................................................................135
8.4 Pulse Compression in Radars ........................................................................138
8.5 Frequency Modulation in Pulse Compression ...............................................138
8.5.1 LFM in Pulse Compression ..............................................................138
8.5.2 Frequency Stepping in Pulse Compression ......................................143
8.5.3 Active Processing in LFM Pulse Compression ................................144
8.6 Phase-Coded Modulation in Pulse Compression ..........................................149
8.6.1 Barker Coding for Pulse Compression .............................................150
8.6.2 Frank Coding for Pulse Compression ..............................................151
Problems ...................................................................................................................153
References ................................................................................................................153
Chapter 9 Synthetic Aperture Radars .......................................................................................155
9.1 Introduction ...................................................................................................155
9.2 SAR History ..................................................................................................155
9.3 SAR General Description ..............................................................................157
9.3.1 Resolution along the LOS Axis ........................................................157
9.3.2 Resolution along the XLOS Axis .....................................................159
9.4 SAR Signal Processing ..................................................................................162
9.5 Radar Equation of the SAR System ..............................................................163
9.6 SAR System Design Consideration ...............................................................165
Problems ...................................................................................................................166
References ................................................................................................................167
