Combat System Sensors – Volume 1
This section addresses those attributes which are common to broad classes of sensor system. For example, the external environment dramatically affects the performance of all sensor systems. Similarly, the ability to perform critical functions such as detection or tracking, can be related to certain universal sensor characteristics in an unambiguous fashion. Among these common attributes are the characteristics of observable signals, the effects of propagation through the environment, and the functions desired to be performed. Other than their use as examples, specific sensor technologies are not discussed until Part II. Specifically, this section describes a set of tools that can be used by the analyst to predict and compare the performance of any kinds of sensor systems. Use of these tools permits apples to apples trade studies to be made between sensors with little or no physical similarity.
In addition, it will become apparent that even after a detailed discussion of radar or sonar components, integration, and operation, the student will be unable to predict the performance of any radar or sonar until after he has learned how to obtain and incorporate the results of detection theory, estimation theory, and propagation theory, among others.
This material is presented first in the hopes of instilling a recognition that sensors can be studied as a unified topic. In this context, attempts to impart special status to certain sensors such as radar or sonar will be seen to be not only superficial and but also potential causes of less–than–optimal designs.
Contents:
Volume I
Sensor Elements.
Part I.
Sensor Functional Characteristics
FOREWORD. INTRODUCTION TO COMBAT SYSTEMS xxv
PREFACE. SENSOR FUNCTIONAL CHARACTERISTICS 1
CHAPTER 1. SIGNATURES, OBSERVABLES, & PROPAGATORS 3
Sensors, Transducers, and Detectors 3
Observables 4
Signatures and Propagators 5
References 11
Problems 12
CHAPTER 2. PROPAGATION OF ELECTROMAGNETIC RADIATION. I.
– FUNDAMENTAL EFFECTS 13
What is Electromagnetic Radiation 13
Attenuation of Electromagnetic Radiation in Bulk Materials 20
Reflection and Refraction 23
Interference 28
Huygens’ Principle and Diffraction 30
Mie Scattering 35
References 37
Problems 38
CHAPTER 3. PROPAGATION OF ELECTROMAGNETIC RADIATION. II.
– WEATHER EFFECTS 39
Introduction 39
Structure of the Atmosphere 45
Molecular Absorption 56
Aerosol Scattering 67
Hydrometeors – Fogs and Clouds 71
Hydrometeors – Precipitation 85
Statistics of Weather Effects 89
References 100
Problems 104
iv
CHAPTER 4. PROPAGATION OF ELECTROMAGNETIC RADIATION. III.
– REFRACTIVE EFFECTS 107
Horizon Extension 107
Ducting and Mirages 114
Atmospheric Turbulence 128
Ionospheric Effects 148
References 154
Problems 156
CHAPTER 5. PROPAGATION OF ELECTROMAGNETIC RADIATION IV.
– OTHER ATMOSPHERIC AND UNDERWATER EFFECTS 159
Contrast Transmission 159
Smoke, Dust, and Battlefield Obscurants 162
Pasquill Stability and Atmospheric Diffusion 168
Transmission Through Stratified Media 176
Multipath 179
Terrain Masking 183
Underwater Propagation 187
References 190
Problems 192
CHAPTER 6. PROPAGATION OF ACOUSTIC RADIATION 195
What is Acoustic Radiation? 195
The Speed of Sound 199
Attenuation of Acoustic Radiation 204
Reflection and Refraction of Acoustic Radiation 215
Seismic Waves 228
References 234
Problems 236
CHAPTER 7. NUCLEAR RADIATION: ITS ORIGIN AND PROPAGATION 239
The Nuclear Radiation Particle Zoo 239
Nuclear Particle Reactions 247
Nuclear Particle Reaction Rates 255
Attenuation of Nuclear Radiation 257
Radiation Exposure and Dose 266
Radioactive Decay 268
References 277
Problems 279
CHAPTER 8. RADIOMETRY, PHOTOMETRY, & RADIOMETRIC ANALYSIS 281
Radiometry 281
Photometry 287
Radiometric Analysis – Range Equations 290
Blackbody Radiation 293
Reflectance 296
References 302
Problems 303
CHAPTER 9. SENSOR FUNCTIONS 305
Uses of Sensor Systems 305
Six Primary Sensor Functions 307
Incidental Sensor Functions 309
Problems 310
CHAPTER 10. SEARCH 311
Introduction to Search 311
Circle Packing 313
Area Search 319
Volume Search 327
Incorporating Effects of Non–Unity Detection Probability into Search 330
References 332
Problems 333
CHAPTER 11. DETECTION 335
What is Detection? 335
Basics of Detection Theory 336
Impact of Signal Fluctuations on Detection 345
Impact of Pulse Integration on Detection 350
Example: Turbulence Effects on Laser Radar Detection 354
System Level Concerns Involving Detection 360
Clutter and Clutter Rejection 362
References 363
Problems 364
CHAPTER 12. ESTIMATION 367
Characteristics of Measurements 367
Sensor Resolution 369
Parameter Estimation 376
Discrimination 379
Pattern Recognition 383
References 386
Problems 387
CHAPTER 13. MODULATION AND DEMODULATION 389
Modulation and Demodulation 389
Amplitude Modulation 394
Frequency Modulation 398
Phase Modulation 402
Pulse Modulation 404
Pulse Code Modulation 406
References 413
Problems 414
CHAPTER 14. IMAGING AND IMAGE–BASED PERCEPTION 415
Generalized Images 415
Resolution versus Coverage 417
Image–Based Perception 422
Johnson’s Criteria 426
Applications of Johnson’s Criteria 429
Information–Based Johnson’s Criteria 435
Example: Atmospheric Turbulence Effects on Laser Radar Images 440
References 446
Problems 448
CHAPTER 15. TRACKING 451
Tracking Systems 451
Tracking Filters 457
Fixed–Coefficient Filters 463
Kalman Filters 471
Comparison of Fixed–Coefficient and Kalman Filters 474
Multisensor, Multiplatform Tracking 475
Target Motion Analysis 479
References 493
Problems 494
APPENDIX A. UNITS, PHYSICAL CONSTANTS, AND USEFUL
CONVERSION FACTORS 497
Units 497
Non–SI Systems of Units 500
Natural Units 505
Decibels and Logarithmic Units 506
Units of Attenuation 510
Dimensional Analysis 512
Useful Physical Constants 515
Selected Conversion Factors 518
Useful Mathematical Relations 521
References 533
APPENDIX B. FINITE DIFFERENCE AND FINITE ELEMENT TECHNIQUES 535
Finite Difference Approximation of Derivatives 535
Finite Difference Solution of Differential Equations 537
Finite Element Computation of Definite Integrals 539
References 540
APPENDIX C. PROBABILITY AND STATISTICS 541
Combinatorial Analysis 541
Probability 543
Random Variables and Functions of Random Variables 546
Statistics 554
Variance and Covariance of Vector Random Functions 557
References 559
INDEX TO VOLUME 1