Table Of Content

Motion and Gesture Sensing with Radar For a complete listing of titles in the Artech House Radar Library, turn to the back of this book. Motion and Gesture Sensing with Radar Jian Wang Jaime Lien Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the U.S. Library of Congress. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Cover design by Andy Meaden Creative ISBN 13: 978-1-63081-823-4 © 2022 ARTECH HOUSE 685 Canton Street Norwood, MA 02062 All rights reserved. Printed and bound in the United States of America. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Artech House cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark. 10 9 8 7 6 5 4 3 2 1 To my wife, Xiaoli; my children, Grace, Karlos, and Victoria; as well as my mom, Yunfeng; and in memory of my father, Chenghong Wang —Jian Wang For Chris and Theo —Jaime Lien Contents Preface xiii 1 Introduction 1 1.1 Radar Basics and Types 2 1.2 Frequency Bands and Civil Applications 5 1.3 Radar Standardization 8 1.4 Book Outline 8 References 9 2 Radar System Architecture and Range Equation 11 2.1 Basic Hardware Components of Radar 11 2.1.1 Transmitter/Receiver (Transceiver) 12 2.1.2 Waveform Generator 15 2.1.3 Antennas 16 2.2 LFM Radar Architecture 19 2.3 Receiver Noise 19 2.4 Dynamic Range 21 vii viii Motion and Gesture Sensing with Radar Contents ix 2.5 Radar Range Equation 22 2.6 Radar System Integration 27 References 28 3 Radar Signal Model and Demodulation 31 3.1 Signal Modeling 31 3.1.1 Point Target 34 3.1.2 Distributed Target 35 3.2 Radar Waveforms and Demodulation 36 3.2.1 Matched Filter 38 3.2.2 Ambiguity Function 43 3.3 Frequency Modulated Waveforms 53 3.3.1 Conventional FMCW Waveforms 56 3.3.2 LFM Chirp Train (Fast Chirp) 62 3.3.3 Stretch Processing 63 3.4 Phase Coded Waveforms 66 3.4.1 Golay Codes 69 3.5 Summary 71 References 72 4 Radar Signal Processing 75 4.1 Range Processing (Fast Time Processing) 77 4.1.1 Minimum Range and Maximum Unambiguous Range 78 4.1.2 Pulse Compression 78 4.1.3 Range Resolution 79 4.1.4 Range Accuracy 83 4.1.5 Time Sidelobes Control 85 4.2 Doppler Processing (Slow Time Processing) 88 4.2.1 Sampling Frequency in Slow Time Domain 92 4.2.2 CIT Window Size 96 4.2.3 MTI and Clutter Cancellation 97 4.2.4 Moving Target Detector (Filter Bank) 101 4.2.5 Doppler (Radial Velocity) Resolution 102 4.2.6 Doppler (Radial Velocity) Accuracy 103 4.2.7 Doppler Sidelobes Control 104 viii Motion and Gesture Sensing with Radar Contents ix 4.3 Summary 105 References 105 5 Array Signal Processing 109 5.1 Array Manifold and Model 110 5.2 Conventional Beamforming 116 5.2.1 Uniform Array and FFT Based Beamforming 118 5.2.2 Array Resolution, Accuracy, and Sidelobes Control 120 5.2.3 Digital Beamforming Versus Analog Beamforming 122 5.3 High-Resolution Methods 122 5.4 MIMO 126 5.4.1 Virtual Array 126 5.4.2 Basic MIMO Waveforms 129 5.4.3 Summary 132 References 133 6 Motion and Presence Detection 135 6.1 Introduction 135 6.2 Detection Theory 136 6.2.1 Hypothesis Testing and Decision Rules 136 6.2.2 Neyman-Pearson Criterion and Likelihood Ratio Test 139 6.3 Signal and Noise Models 140 6.3.1 Target RCS Fluctuations 140 6.3.2 Noise 143 6.4 Threshold Detection 144 6.4.1 Optimal Detection of Nonfluctuating Target 144 6.4.2 Detection Performance 146 6.4.3 Impact of Target Fluctuation 148 6.5 Constant False Alarm Rate Detection 149 6.5.1 Cell-Averaging CFAR 151 6.5.2 Greatest-of and Least-of CFAR 152 6.5.3 Ordered Statistics CFAR 153 6.6 Clutter Rejection 153 6.6.1 Regions of Interest 154