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| Preface | |
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| Acknowledgments | |
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| Abbreviations | |
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| Introduction | |
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| Background and Motivation | |
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| Line-of-Sight Radars | |
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| Coverage Limitations | |
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| Beyond the Horizon | |
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| OTH Radar Principles | |
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| Operational Concept | |
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| General Characteristics | |
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| Practical Applications | |
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| HF Radar Equation | |
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| Slant Range | |
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| Transmit Power | |
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| Antenna Gains | |
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| Target RCS | |
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| Integration Time | |
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| Total Losses | |
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| Propagation Factor | |
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| Ambient Noise | |
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| Numerical Example | |
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| Nominal System Capabilities | |
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| Minimum and Maximum Range | |
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| Dwell Illumination Region | |
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| Resolution and Accuracy | |
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| Fundamental Principles | |
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| Skywave Propagation | |
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| The Ionosphere | |
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| Historical Overview | |
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| Formation and Structure | |
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| The D-, E-, and F-Regions | |
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| Spatial and Temporal Variability | |
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| Radio Sounding at Vertical Incidence | |
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| Measurements and Models | |
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| Disturbances and Storms | |
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| Oblique Propagation | |
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| Equivalence Relationships | |
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| Point-to-Point Links | |
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| Frequency, Elevation, and Ground Range | |
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| Ionospheric Modes | |
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| Ordinary and Extraordinary Waves | |
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| Multipath Propagation | |
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| Amplitude and Phase Fading | |
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| System Characteristics | |
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| Preliminary Considerations | |
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| Configuration and Site Selection | |
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| Radar Waveforms | |
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| Out-of-Band Emissions | |
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| Radar Architecture | |
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| Transmit System | |
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| Receive System | |
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| Array Calibration | |
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| Frequency Management | |
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| Propagation-Path Assessment | |
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| Channel Occupancy and Noise | |
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| Ionospheric Mode Structure | |
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| Historical Perspective | |
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| Past and Present Systems | |
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| OTH Radar in Australia | |
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| Future Prospects | |
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| Conventional Processing | |
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| Signal Environment | |
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| Target Echoes | |
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| Clutter Returns | |
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| Noise and Interference | |
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| Standard Routines | |
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| Pulse Compression | |
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| Array Beamforming | |
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| Doppler Processing | |
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| Operational Considerations | |
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| Air and Surf ace Tasks | |
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| Transient Disturbance Mitigation | |
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| Data Extrapolation and Signal Conditioning | |
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| Detection and Tracking | |
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| Constant False-Alarm Rate Processing | |
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| Threshold Detection and Peak Estimation | |
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| Tracking and Coordinate Registration | |
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| Surface-Wave Radar | |
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| General Characteristics | |
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| Principle of Operation | |
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| Architecture and Capabilities | |
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| Practical Applications | |
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| Propagation Mechanism | |
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| Short and Long Distances | |
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| Tropospheric Refraction | |
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| Surface Roughness and Heterogeneity | |
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| Environmental Factors | |
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| Sea Clutter | |
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| Ionospheric Clutter | |
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| Interference and Noise | |
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| Practical Implementation | |
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| Configuration and Siting | |
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| Radar Subsystems | |
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| Signal and Data Processing | |
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| Operational Considerations | |
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| Radar Cross Section | |
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| Multi-Frequency Operation | |
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| Example Systems | |
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| Signal Description | |
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| Wave-Interference Model | |
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| Deterministic Description | |
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| Background and Scope | |
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| Gross Structure of Composite Wavefields | |
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| Fine Structure of Individual Modes | |
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| Channel Scattering Function | |
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| Ionospheric Mode Identification | |
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| Nominal Mode Parameters | |
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| Fine Structure Observations | |
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| Resolving Fine Structure | |
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| Signal Representation | |
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| Parameter Estimation | |
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| Space-Time MUSIC | |
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| Experimental Results | |
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| Preliminary Data Analysis | |
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| Model-Fitting Accuracy | |
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| Summary and Discussion | |
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| Statistical Signal Model | |
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| Stationary Processes | |
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| Background and Scope | |
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| Measurements on HF Signals | |
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| Extension to Antenna Arrays | |
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| Diffuse Scattering | |
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| Mathematical Representation | |
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| Varying Ionospheric Structure | |
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| Auto-Correlation Functions | |
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| Temporal Statistics | |
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| Parameter Estimation Method | |
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| Hypothesis Acceptance Test | |
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| Spatial Homogeneity Assumption | |
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| Spatial and Space-Time Statistics | |
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| Correlation Coefficients | |
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| Mean Plane Wavefront | |
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| Space-Time Separability | |
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| HF Channel Simulator | |
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| Point and Extended Sources | |
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| Traditional Array-Processing Models | |
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| Coherent and Incoherent Ray Distributions | |
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| Parametric Localization of Distributed Signals | |
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| Generalized Watterson Model | |
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| Mathematical Formulation and Interpretation | |
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| Temporal and Spatial Fluctuations | |
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| Expected Second-Order Statistics | |
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| Parameter-Estimation Techniques | |
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| Standard Identification Procedures | |
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| Matched-Field MUSIC Algorithm | |
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| Polynomial Rooting Method | |
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| Real-Data Application | |
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| Closed-Form Least Squares | |
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| Subspace-Based Approach | |
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| Summary and Discussion | |
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| Interference Cancelation Analysis | |
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| Interference and Noise Mitigation | |
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| Spatial Processing | |
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| Popular Techniques | |
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| HF Applications | |
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| Standard Adaptive Beamforming | |
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| Sample Matrix Inverse Technique | |
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| Practical Implementation Schemes | |
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| Alternative Time-Varying Approach | |
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| Instantaneous Performance Analysis | |
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| Real-Data Collection | |
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| Intra-CPI Performance Analysis | |
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| Output SINR Improvement | |
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| Statistical Performance Analysis | |
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| Framing Schemes | |
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| Batch Schemes | |
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| Operational Issues | |
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| Simulated Performance Prediction | |
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| Multi-Channel Model Parameters | |
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| Impact of Wavefront Distortions | |
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| Summary and Discussion | |
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| Processing Techniques | |
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| Adaptive Beamforming | |
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| Essential Concepts | |
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| Optimum and Adaptive Filters | |
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| Homogeneous Gaussian Case | |
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| Real-World Environments | |
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| Problem Formulation | |
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| Interference and Clutter Mitigation | |
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| Multi-Channel Data Model | |
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| Standard Adaptive Beamforming | |
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| Time-Varying Approaches | |
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| Stochastic Constraints | |
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| Time-Varying Spatial Adaptive Processing | |
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| Experimental Results | |
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| Post-Doppler Techniques | |
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| Motivating Practical Application | |
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| Range-Dependent Adaptive Beamforming | |
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| Extended Data Analysis | |
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| Space-Time Adaptive Processing | |
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| STAP Architectures | |
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| Slow-Time STAP | |
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| Fast-Time STAP | |
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| 3D-STAP | |
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| Data Model | |
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| Composite Signal | |
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| Cold Clutter | |
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| Hot Clutter | |
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| Mitigation Techniques | |
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| Standard Schemes | |
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| Alternative Procedures | |
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| Simulation Results | |
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| Post-Doppler STAP Implementation | |
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| Algorithm Description | |
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| Experimental Results | |
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| Discussion | |
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| GLRT Detection Schemes | |
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| Problem Description | |
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| Background and Motivation | |
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| Traditional Hypothesis Test | |
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| Alternative Binary Tests | |
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| Measurement Models | |
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| Disturbance Process | |
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| Useful Signal | |
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| Coherent Interference | |
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| Processing Schemes | |
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| One-and Two-Step GLRT | |
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| Partially Homogeneous Case | |
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| Joint Data-Set Detection | |
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| Practical Applications | |
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| Spatial Processing | |
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| Temporal Processing | |
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| Hybrid Technique | |
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| Blind Waveform Estimation | |
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| Problem Formulation | |
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| Multipath Model | |
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| Processing Objectives | |
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| Motivating Example | |
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| Standard Techniques | |
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| Blind System Identification | |
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| Blind Signal Separation | |
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| Discussion | |
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| GEMS Algorithm | |
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| Noiseless Case | |
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| Operational Procedure | |
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| Computational Complexity | |
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| SIMO Experiment | |
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| Data Collection | |
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| Signal-Copy Methods | |
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| Application of GEMS | |
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| MTMO Experiment | |
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| Data Collection | |
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| Source and Multipath Separation | |
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| Radar Application | |
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| Single-Site Geolocation | |
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| Background and Motivation | |
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| Data Collection | |
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| Geolocation Method | |
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| Summary and Future Work | |
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| Appendixes and Bibliography | |
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| Sample ACS Distribution | |
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| Space-Time Separability | |
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| Modal Decomposition | |
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| Bibliography | |
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| Index | |