Pulse Doppler Radar: Principles, Technology, Applications

Pulse Doppler Radar: Principles, Technology, Applications......Page 4
Brief Contents......Page 6
Contents......Page 8
Preface......Page 12
Author Acknowledgements......Page 14
Publisher Acknowledgements......Page 15
PART I: Basic Concepts......Page 16
1 Historical Justification for Pulse Doppler Radar......Page 18
2.1.1 Derivation of the Basic Radar Range Equation......Page 22
2.1.2 Losses......Page 24
2.2.1 Threshold Detection......Page 25
2.2.2 Cumulative Probability of Detection......Page 28
2.3.2 Noise Figure......Page 29
2.3.3 Minimum Input Signal......Page 30
2.4.3 Quantifying the Benefits of Integration......Page 31
2.4.4 Integration Improvements in the Radar Range Equation......Page 34
2.5.1 Definition......Page 35
2.5.2 Factors Determining RCS......Page 36
2.5.4 The Swerling Models of RCS Fluctuation......Page 37
2.5.5 SNR Requirements as a Result of Target Fluctuation......Page 38
3.1.1 Pulse Repetition Frequency......Page 40
3.3.1 Range as a Measure of Time Delay......Page 41
3.3.4 Range Gating......Page 42
3.4.1 Range Ambiguity......Page 43
3.5.1 Theory of the Spectrum of a Pulsed Carrier......Page 44
3.5.2 Spectral Containment......Page 45
3.6.1 Theory of Matched Reception......Page 46
3.6.2 Ideal and Practical Matched Filtering......Page 48
3.7.1 Factors Degrading Range Resolution......Page 50
3.7.2 Terminology......Page 51
3.8.3 Accuracy and Resolution......Page 52
3.9.2 Pulse Compression Waveforms......Page 53
3.9.3 Theory of Pulse Compression......Page 54
3.9.5 Compression Ratio......Page 55
3.9.6 Range Sidelobes......Page 56
3.9.8 Doppler Corruption......Page 57
4.1.1 The Doppler Shift......Page 58
4.1.3 The Doppler Shift for Pulsed Radar......Page 59
4.1.5 Proportional Doppler Shift......Page 60
4.2 Doppler Discrimination......Page 61
4.3.2 Ground Referenced Velocities......Page 62
4.4.2 Ground-to-Air Case of Blindness at the Zero Crossing Point......Page 63
4.5.1 Doppler Sensing CW Systems......Page 64
4.5.3 Doppler/Velocity Gating......Page 66
4.6.1 Baseband Waveform......Page 67
4.6.2 Doppler Ambiguity......Page 68
5.1 Ambiguity Diagrams......Page 70
5.1.2 Ambiguity Diagram for Linear Frequency Modulation Chirp......Page 71
5.1.3 Ambiguity Diagram for a 13-Bit Barker Coded Biphase Modulated Pulse......Page 73
5.1.4 Ambiguity Diagram for Low Pulse Repetition Frequency Pulse Train......Page 74
5.2 Peak and Integrated Sidelobe Levels......Page 75
6.1 Concepts of Clutter......Page 76
6.2.2 Surface Roughness......Page 77
6.2.3 Sea Surface Backscatter......Page 78
6.2.5 Sea Surface Backscatter as a Function of Grazing Angle......Page 79
6.3.2 Rician Clutter......Page 82
6.3.3 Log-Normal Clutter......Page 84
6.3.4 Weibull Clutter......Page 86
6.3.6 Cumulative Probability Density Functions......Page 88
6.4.1 The Airborne Scenario......Page 89
6.4.2 Clutter Spread in the Range and Velocity Dimensions......Page 90
6.4.3 The Ideal Clutter Map......Page 91
6.4.4.1 Effect of Main Beam Beamwidth......Page 92
6.4.4.2 Internal Clutter Motion......Page 93
6.5.1 Clutter Decorrelation with Time......Page 94
6.6.2 Low PRF Response to Clutter in the Velocity Domain......Page 96
6.7 Clutter-Limited Detection Range......Page 97
6.7.1 Range Resolution-Limited Case......Page 98
6.7.2 Beamwidth-Limited Case......Page 99
6.8 Clutter for a Surface-Based Radar......Page 100
6.9 Volume Clutter......Page 101
7.4 Constant False Alarm Rate Detection......Page 104
7.2.1 The Baseband Signal......Page 105
7.2.2 Single Delay Line Canceler......Page 106
7.2.3 Double Delay Line Canceler......Page 111
7.2.4 Multiple Delay Line Cancelers......Page 112
7.2.5 Three-Pulse Canceler......Page 113
7.2.6 Transversal Filters......Page 114
7.2.7 Digital MTI Cancellation......Page 116
7.2.8 Quantifying MTI Performance......Page 117
7.3 FFT Processing......Page 119
7.3.1 Intuitive Approach to the DFT......Page 120
7.3.2 Analytical Approach to the DFT......Page 122
7.3.3 The Fast Fourier Transform......Page 125
7.3.4 The Windowed Discrete Fourier Transform......Page 131
7.3.6 Zero Padding and DFT Size......Page 133
7.4.1 The Limitations of Fixed Threshold Detection......Page 134
7.4.3 CFAR Loss......Page 135
7.4.4 Cell Averaging CFAR (CACFAR)......Page 136
7.4.5 Greatest-of CFAR (GOCFAR)......Page 140
7.4.7 Ordered Statistic CFAR (OSCFAR)......Page 141
7.4.8 Clutter Maps......Page 142
7.4.9 Binary Integrator......Page 144
7.4.10 Hybrid Approaches......Page 145
8.1 Introduction......Page 146
8.2 Radar Transmitters......Page 147
8.2.1 The Necessity for Coherency......Page 148
8.2.2.1 Spectrum Analysis......Page 149
8.2.2.3 Origin of Close-to-Carrier Noise......Page 150
8.2.2.5 Close-to-Carrier Phase Noise Measurement......Page 151
8.2.2.7 Delay Line Frequency Discriminator Technique......Page 153
8.2.2.9 Setting the Specification......Page 154
8.2.2.10 Example......Page 156
8.2.3.1 Structure......Page 158
8.2.3.2 Operation......Page 160
8.2.3.5 Modes of Oscillation......Page 161
8.2.4.2 Operation......Page 163
8.2.4.5 The Extended Interaction Klystron, EIK......Page 165
8.2.5.2 Operation......Page 166
8.2.6 Comparison of High-Power Tubes......Page 167
8.2.9 The Gallium Arsenide (GaAs) Field Effect Transistor (FET)......Page 168
8.2.13 Gunn Diode......Page 169
8.3 Frequency Synthesizers......Page 170
8.3.1 Direct Digital Synthesizers......Page 171
8.3.2 Direct Analog Synthesizers......Page 172
8.3.3 Indirect Synthesizers, Phase-Locked Loops......Page 173
8.4.1 The Superheterodyne Receiver......Page 176
8.4.1.2 Blind Phases......Page 183
8.4.1.3 The Quadrature Detector......Page 184
8.4.2.1 Introduction......Page 186
8.4.2.2 Thermal Noise......Page 187
8.4.2.5 Noise Figure......Page 188
8.4.2.6 Added Noise......Page 190
8.4.2.8 Cascaded Noise Figure......Page 191
8.4.2.9 Noise Figure of a Passive Device......Page 192
8.5.1 Basic Concepts......Page 193
8.5.1.1 Antenna Gain......Page 194
8.5.1.4 Radiation Pattern......Page 195
8.5.1.5 Tapered Illumination Functions......Page 196
8.5.1.8 Polarization......Page 197
8.5.2.1 Waveguide Horns......Page 198
8.5.2.3 Cassegrain Antenna......Page 199
8.5.3.1 Two-Element Linear Array......Page 200
8.5.3.3 N-Element Linear Array......Page 201
8.5.3.4 Planar Arrays......Page 202
8.5.3.5 Conformal Arrays......Page 203
8.5.4.2 Phase Shifters......Page 204
8.5.4.4 Beam Dilation......Page 205
8.5.4.5 Transmit/Receive Modules......Page 206
8.5.4.6 Advantages of AESA Antennas over Conventional Mechanically Steered Antennas......Page 207
References......Page 209
PART IIA: High Pulse Repetition Frequency Pulse Doppler Radar......Page 212
9.1.1 A Review of the Problems of Low Pulse Repetition Frequency......Page 214
9.1.2 A Brief Overview of High PRF Pulse Doppler......Page 215
9.2.1 The Doppler Band......Page 216
9.2.3 Maximum Unambiguous Doppler/Velocity......Page 218
9.2.6 High PRF Ambiguity Diagram......Page 219
9.2.7 Offsetting the Doppler Band......Page 220
9.2.8 Dependence on Carrier Frequency......Page 221
9.3.1 Duty Ratio......Page 223
9.3.2 Eclipsing Losses and Blind Ranges......Page 224
9.3.3 Ranging in High PRF......Page 226
9.3.4 Range Gated High PRF......Page 227
9.3.6 Other High PRF Ranging Techniques......Page 228
9.4.1 Distribution of Clutter in the Doppler Domain......Page 229
9.4.2 Distribution of Clutter in the Range Domain......Page 233
9.4.3 Distribution of Clutter in Range and Doppler......Page 234
9.5 Surface-Based High PRF Radars......Page 237
9.6 Summary of the Characteristics of High PRF......Page 240
10.1.1 Linear Frequency Modulation Ranging......Page 242
10.1.2 Stepped Frequency Continuous Wave......Page 244
10.1.3 Two-Phase Linear FM Ranging......Page 245
10.1.4 Space Charging......Page 247
10.1.5 Two Phase Linear FM with Doppler......Page 248
10.1.6 Selecting the Modulation Parameters......Page 250
10.1.7 Problems of CW Systems......Page 252
10.2.1 Three-Phase FM Interrupted Continuous Wave......Page 253
10.2.2 Sine Wave FM Ranging (Sine FM)......Page 255
References......Page 261
PART IIB: Medium Pulse Repetition Frequency Pulse Doppler Radar......Page 262
11.1.2 Use of Multiple Coherent Processing Intervals......Page 264
11.1.3 Detection Criterion......Page 265
11.2.1 Maximum Unambiguous Range and Velocity......Page 266
11.2.2 Range and Velocity Space of Interest......Page 267
11.2.4 Range and Velocity Ambiguities......Page 268
11.3.1 Distribution of Clutter in the Doppler Domain......Page 270
11.3.2 Distribution of Clutter in the Range Domain......Page 271
11.3.3 Distribution of Clutter in Range and Doppler......Page 273
11.4 Blindness in Medium PRF Radar......Page 277
11.5 Multiple PRF Schedules......Page 278
12.1.1 Introduction......Page 280
12.1.2 Decodability Constraints......Page 281
12.1.4 Decodability Using Two and Three PRFs—Decodability Margins......Page 282
12.1.5 The Coincidence Algorithm......Page 285
12.1.6 The Chinese Remainder Algorithm......Page 288
12.2.1 Blind Zone Maps......Page 291
12.2.3 Blindness Margins......Page 293
12.3.1.2 Eclipsing Losses......Page 297
12.3.3 Mean PRF......Page 298
12.4.2 Cross-Correlation of Multiple Targets......Page 300
12.4.3 Noise-Generated Ghosts......Page 304
12.4.4 Self-Ghosting Due to Extended Target Responses......Page 305
12.4.5 Decodability Margins and their Depiction Using Skyline Diagrams......Page 306
12.4.6 PRF Selection to Minimize Ghosting......Page 309
12.4.7 Orbits of Ghosts......Page 310
12.4.8.2 Formations of Multiple Targets with Similar Velocities Moving Radially......Page 311
12.5.2 Combating Ghosting via the Correlation in Range and Velocity......Page 312
12.5.3 Target Clustering and Extraction Algorithms Using a Maximum Likelihood Method......Page 313
12.5.4 Combating Ghosting via the Target Extraction Algorithm......Page 314
12.5.5 Target Extraction Algorithms Based on Non-Coherent Integration......Page 316
12.5.6 Combating Ghosting via Target Data Consistency......Page 317
12.5.7 Decorrelating Ghost Tracks Using Multiple PRF Schedules......Page 318
12.5.8 Summary of Ghosting......Page 319
13.1.1 Introduction......Page 322
13.1.2 Selection of M......Page 323
13.1.3 Selection of N......Page 324
13.2.1 Introduction......Page 325
13.2.2 Decodability......Page 326
13.2.3 Blindness......Page 327
13.2.4 Ghosting......Page 330
13.2.5 Clutter-Limited versus Noise-Limited Cases......Page 332
13.3.1 Implications for Single Target Tracking Radars......Page 333
13.3.2 Frequency Agility......Page 335
14.1.1 Classical Detection Theory......Page 338
14.1.2 Effect of Blindness......Page 339
14.1.3 Effects of Target Scintillation......Page 342
14.1.6 Optimum Duty Ratio......Page 343
14.2.2 Optimal Constant False Alarm Rate Design......Page 346
14.2.2.2 Optimum CFAR Window......Page 347
14.2.2.3 CFAR Performance Variation with M = 3, 4 for Realistic Data......Page 348
14.2.2.4 CACFAR versus OSCFAR......Page 349
14.2.3 Detectability Maps......Page 350
14.2.4 Optimization for Clutter Statistics......Page 351
14.2.5 Aperture Illumination Function......Page 352
15.1 A Brief Review of the Pulse Repetition Frequency Selection Requirements......Page 354
15.2 PRF Selection for Maximum Visibility......Page 355
15.3 Major–Minor Method of PRF Selection......Page 356
15.4 M:N Method of PRF Selection......Page 359
15.5 Exhaustive Search......Page 361
15.7.1 Introduction to Evolutionary Algorithms......Page 363
15.7.1.4 Evolutionary Strategies......Page 365
15.7.2 PRF Selection for Minimal Blindness Using Evolutionary Algorithms......Page 366
15.7.3 PRF Selection for Optimal Target Detectability Using Evolutionary Algorithms......Page 368
15.7.4 PRF Selection Using Multi-Objective Evolutionary Algorithms......Page 369
15.8 Concluding Remarks......Page 371
References......Page 372
PART III: Case Studies......Page 376
16.1 Introduction......Page 378
16.2.2 Techniques......Page 379
16.2.3.2 Antenna......Page 381
16.3.1 Typical Radar Parameters......Page 382
16.3.2 Blindness Performance......Page 383
16.3.3 Decodability Margins......Page 384
17.1.2 Problems of AEW Systems......Page 386
17.1.4 Example AEW Systems......Page 387
17.2 AEW Radar for Fleet Protection......Page 388
17.3 AEW Radar for Long-Range Air Surveillance......Page 389
18.1 Introduction......Page 392
18.2.1 Medium-Range Air-to-Air (Semi-active Homing)......Page 393
18.2.2 Medium-Range Air-to-Air (Active Homing)......Page 394
18.2.4 Air-Launched Anti-armor Missiles......Page 395
18.2.6 Gun-Launched Antia-Armor Munitions......Page 396
18.3.1.1 Pursuit Guidance......Page 397
18.3.1.2 Proportional Navigation (PN)......Page 398
18.3.2 Warhead......Page 399
18.4.2 Seeker Parameters......Page 400
18.4.4 Range Walk......Page 401
19.1 Introduction......Page 404
19.2 Differences in the Clutter Situation between Airborne and Ground-Based Pulse Doppler Radars......Page 405
19.3.2 Stacked Beams......Page 406
19.3.3 Cosecant Squared Radiation Pattern......Page 407
19.4.3 Threat Evaluation......Page 409
19.4.4 Radar Parameters......Page 410
References......Page 411
Closing Remarks......Page 412
Index......Page 414