Fundamentals of Radar Signal Processing

Preface......Page 15
Acknowledgments......Page 19
Symbols......Page 20
Acronyms......Page 30
1.1    History and Applications of Radar......Page 35
1.2    Basic Radar Functions......Page 37
1.3    Elements of a Pulsed Radar......Page 40
1.3.1    Transmitter and Waveform Generator......Page 41
1.3.2    Antennas......Page 45
1.3.3    Receivers......Page 53
1.4.1    Signal-to-Interference Ratio and Integration......Page 58
1.4.2    Resolution......Page 59
1.4.3    Data Integration and Phase History Modeling......Page 63
1.4.4    Bandwidth Expansion......Page 66
1.5    A Preview of Basic Radar Signal Processing......Page 68
1.5.1    Radar Time Scales......Page 69
1.5.3    Signal Conditioning and Interference Suppression......Page 71
1.5.4    Imaging......Page 76
1.5.5    Detection......Page 78
1.5.6    Measurements and Track Filtering......Page 80
1.6.1    Radar Systems and Components......Page 81
1.6.3    Advanced Radar Signal Processing......Page 82
References......Page 83
Problems......Page 85
2.1    Components of a Radar Signal......Page 89
2.2.1    Simple Point Target Radar Range Equation......Page 90
2.2.2    Distributed Target Forms of the Range Equation......Page 94
2.2.3    Radar Cross Section......Page 101
2.2.4    Radar Cross Section for Meteorological Targets......Page 104
2.2.5    Statistical Description of Radar Cross Section......Page 106
2.2.6    Target Fluctuation Models......Page 125
2.2.7    Swerling Models......Page 129
2.2.8    Effect of Target Fluctuations on Doppler Spectrum......Page 131
2.3    Clutter......Page 132
2.3.1    Behavior of σ 0......Page 133
2.3.3    Temporal and Spatial Correlation of Clutter......Page 136
2.3.4    Compound Models of Radar Cross Section......Page 140
2.4    Noise Model and Signal-to-Noise Ratio......Page 142
2.6.1    Doppler Shift......Page 147
2.6.2    The Stop-and-Hop Approximation and Phase History......Page 152
2.6.3    Measuring Doppler Shift: Spatial Doppler......Page 155
2.7.1    Coherent Scattering......Page 157
2.7.2    Variation with Angle......Page 160
2.7.3    Variation with Range......Page 163
2.7.4    Noncoherent Scattering......Page 164
2.7.5    Projections......Page 165
2.7.6    Multipath......Page 166
2.8    Spectral Model......Page 167
2.9    Summary......Page 169
References......Page 170
Problems......Page 172
3.1.1    One Pulse: Fast Time......Page 180
3.1.2    Multiple Pulses: Slow Time and the CPI......Page 184
3.1.3    Doppler and Range Ambiguities......Page 188
3.1.4    Multiple Channels: The Datacube......Page 192
3.1.5    Dwells......Page 194
3.2.1    The Nyquist Rate in Doppler......Page 195
3.2.2    Straddle Loss......Page 198
3.3.1    Spatial Array Sampling......Page 203
3.3.2    Sampling in Angle......Page 205
3.4.1    I/Q Imbalance and Offset......Page 208
3.4.2    Correcting I/Q Errors......Page 212
3.4.3    Digital I/Q......Page 215
Problems......Page 222
4.1    Introduction......Page 226
4.2.1    The Matched Filter......Page 228
4.2.2    Matched Filter for the Simple Pulse......Page 231
4.2.3    All-Range Matched Filtering......Page 233
4.2.4    Straddle Loss......Page 234
4.2.5    Range Resolution of the Matched Filter......Page 235
4.3    Matched Filtering of Moving Targets......Page 236
4.4.1    Definition and Properties of the Ambiguity Function......Page 239
4.4.2    Ambiguity Function of the Simple Pulse......Page 243
4.5    The Pulse Burst Waveform......Page 247
4.5.1    Matched Filter for the Pulse Burst Waveform......Page 248
4.5.2    Pulse-by-Pulse Processing......Page 250
4.5.3    Range Ambiguity......Page 252
4.5.4    Doppler Response of the Pulse Burst Waveform......Page 255
4.5.5    Ambiguity Function for the Pulse Burst Waveform......Page 257
4.5.6    The Slow-Time Spectrum and the Periodic Ambiguity Function......Page 263
4.6    Frequency-Modulated Pulse Compression Waveforms......Page 264
4.6.1    Linear Frequency Modulation......Page 265
4.6.2    The Principle of Stationary Phase......Page 270
4.6.3    Ambiguity Function of the LFM Waveform......Page 272
4.6.4    Range-Doppler Coupling......Page 276
4.6.5    Stretch Processing......Page 277
4.7    Range Sidelobe Control for FM Waveforms......Page 283
4.7.1    Matched Filter Frequency Response Shaping......Page 284
4.7.2    Matched Filter Impulse Response Shaping......Page 288
4.7.3    Waveform Spectrum Shaping......Page 289
4.8    The Stepped Frequency Waveform......Page 294
4.10    Phase-Modulated Pulse Compression Waveforms......Page 300
4.10.1    Biphase Codes......Page 301
4.10.2    Polyphase Codes......Page 310
4.10.3    Mismatched Phase Code Filters......Page 316
4.11    Costas Frequency Codes......Page 317
References......Page 319
Problems......Page 321
5    Doppler Processing......Page 327
5.1    Moving Platform Effects on the Doppler Spectrum......Page 329
5.2    Moving Target Indication......Page 335
5.2.1    Pulse Cancellers......Page 338
5.2.2    Vector Formulation of the Matched Filter......Page 342
5.2.3    Matched Filters for Clutter Suppression......Page 344
5.2.4    Blind Speeds and Staggered PRFs......Page 349
5.2.5    MTI Figures of Merit......Page 357
5.2.6    Limitations to MTI Performance......Page 363
5.3    Pulse Doppler Processing......Page 367
5.3.1    The Discrete-Time Fourier Transform of a Moving Target......Page 369
5.3.2    Sampling the DTFT: The Discrete Fourier Transform......Page 374
5.3.3    The DFT of Noise......Page 376
5.3.5    Matched Filter and Filterbank Interpretations of Pulse Doppler Processing with the DF T......Page 377
5.3.6    Fine Doppler Estimation......Page 381
5.3.7    Modern Spectral Estimation in Pulse Doppler Processing......Page 389
5.3.8    CPI-to-CPI Stagger and Blind Zone Maps......Page 391
5.4    Pulse Pair Processing......Page 398
5.5.1    Combined MTI and Pulse Doppler Processing......Page 405
5.5.2    Transient Effects......Page 406
5.5.3    PRF Regimes......Page 407
5.5.4    Ambiguity Resolution......Page 415
5.6.1    Clutter Mapping......Page 419
5.6.2    The Moving Target Detector......Page 421
5.7    MTI for Moving Platforms: Adaptive Displaced Phase Center Antenna Processing......Page 422
5.7.1    The DPCA Concept......Page 423
5.7.2    Adaptive DPCA......Page 426
References......Page 431
Problems......Page 433
6    Detection Fundamentals......Page 440
6.1    Radar Detection as Hypothesis Testing......Page 441
6.1.1    The Neyman-Pearson Detection Rule......Page 442
6.1.2    The Likelihood Ratio Test......Page 443
6.2    Threshold Detection in Coherent Systems......Page 454
6.2.1    The Gaussian Case for Coherent Receivers......Page 456
6.2.2    Unknown Parameters and Threshold Detection......Page 460
6.2.3    Linear and Square-Law Detectors......Page 468
6.2.4    Other Unknown Parameters......Page 470
6.3    Threshold Detection of Radar Signals......Page 471
6.3.1    Coherent, Noncoherent, and Binary Integration......Page 472
6.3.2    Nonfluctuating Targets......Page 474
6.3.3    Albersheim’s Equation......Page 480
6.3.4    Fluctuating Targets......Page 483
6.3.5    Shnidman’s Equation......Page 489
6.4    Binary Integration......Page 492
6.5.1    The Effect of Unknown Interference Power on False Alarm Probability......Page 496
6.5.2    Cell-Averaging CFAR......Page 499
6.5.3    Analysis of Cell-Averaging CFAR......Page 503
6.5.4    CA CFAR Limitations......Page 509
6.5.5    Extensions to Cell-Averaging CFAR......Page 516
6.5.6    Order Statistic CFAR......Page 523
6.5.7    Additional CFAR Topics......Page 528
6.6    System-Level Control of False Alarms......Page 535
References......Page 536
Problems......Page 539
7    Measurements and Tracking......Page 544
7.1.1    Estimator Properties......Page 548
7.1.2    The Cramèr-Rao Lower Bound......Page 551
7.1.3    The CRLB and Signal-to-Noise Ratio......Page 553
7.1.4    Maximum Likelihood Estimators......Page 555
7.2.1    Range Estimators......Page 556
7.2.2    Doppler Signal Estimators......Page 573
7.2.3    Angle Estimators......Page 584
7.3.1    Sequential Least Squares Estimation......Page 606
7.3.2    The α – β Filter......Page 614
7.3.3    The Kalman Filter......Page 620
7.3.4    The Tracking Cycle......Page 628
References......Page 635
Problems......Page 636
8    Introduction to Synthetic Aperture Imaging......Page 643
8.1.1    Cross-Range Resolution in Radar......Page 648
8.1.2    The Synthetic Aperture Viewpoint......Page 651
8.1.3    Doppler Viewpoint......Page 661
8.1.4    SAR Coverage and Sampling......Page 663
8.2.1    Stripmap SAR Geometry......Page 668
8.2.2    Stripmap SAR Data Set......Page 672
8.3    Stripmap SAR Image Formation Algorithms......Page 676
8.3.1    Doppler Beam Sharpening......Page 678
8.3.2    Quadratic Phase Error Effects......Page 682
8.3.3    Range-Doppler Algorithms......Page 690
8.3.4    Depth of Focus......Page 698
8.4    Spotlight SAR Data Characteristics......Page 699
8.5    The Polar Format Image Formation Algorithm for Spotlight SAR......Page 706
8.6.1    The Effect of Height on a SAR Image......Page 709
8.6.2    IFSAR Processing Steps......Page 713
8.7.1    Motion Compensation and Autofocus......Page 719
8.7.2    Autofocus......Page 723
8.7.3    Speckle Reduction......Page 734
References......Page 736
Problems......Page 739
9    Introduction to Beamforming and Space-Time Adaptive Processing......Page 744
9.1.1    Beamforming......Page 745
9.1.2    Adaptive Beamforming......Page 749
9.1.3    Adaptive Beamforming with Preprocessing......Page 756
9.2    Space-Time Signal Environment......Page 759
9.3    Space-Time Signal Modeling......Page 764
9.4.1    Optimum Matched Filtering......Page 769
9.4.2    STAP Metrics......Page 770
9.4.3    Relation to Displaced Phase Center Antenna Processing......Page 777
9.4.4    Adaptive Matched Filtering......Page 781
9.5    Reduced-Dimension STAP......Page 784
9.6    Advanced STAP Algorithms and Analysis......Page 786
9.7    Limitations to STAP......Page 788
References......Page 790
Problems......Page 791
A   Selected Topics in Probability and Random Processes......Page 795
B   Selected Topics in Digital Signal Processing......Page 834
Index......Page 868