Elint : The Interception and Analysis of Radar Signals

by Wiley, Richard G.

• ISBN13: 9781580539258
• ISBN10: 1580539254
• Edition: 1st
• Format: Hardcover
• Copyright: 2006-04-30
• Publisher: Artech House on Demand

Summary

In these times correctly and quickly identifying a stray electronic blip on a radar screen can have incalculable consequences. Now more than ever, radar electronic intelligence (ELINT) can be the first line of defense for the battlefield or the homeland. Offering new insight into radar signal analysis, this book ensures more reliable and timely gathering of electronic intelligence. Combining and updating the author's two previous definitive books on ELINT, this volume is the indispensable reference for every ELINT professional.

Author Biography

Richard G. Wiley is currently the vice president and chief scientist of Research Associates of Syracuse, Inc., and an instructor in the continuing education programs in engineering for Research Associates of Syracuse and for the Association of Old Crows (AOC)

Table of Contents

Preface	xiii
CHAPTER 1 Electronic Intelligence	1	(8)
1.1 Electronic Intelligence Defined	1	(1)
1.2 The Importance of Intercepting and Analyzing Radar Signals	2	(2)
1.3 Limitations Due to Noise	4	(1)
1.4 Probability of Intercept Problems	4	(1)
1.5 Direction Finding (DF) and Emitter Location	5	(1)
1.6 Inferring Radar Capabilities from Observed Signal Parameters	5	(1)
1.7 Receivers for Radar Interception	6	(1)
1.8 Major ELINT Signal Parameters	6	(1)
1.9 The Impact of LPI Radar on ELINT	7	(1)
References	8	(1)
CHAPTER 2 ELINT Implications of Range Equations and Radar Constraints	9	(20)
2.1 Range Equations	9	(3)
2.2 Radar Constraints	12	(11)
2.2.1 Range Resolution Related to Bandwidth	13	(1)
2.2.2 Spread Spectrum: Radar Versus Communications	14	(1)
2.2.3 Moving Targets and Integration Time Constraints	15	(1)
2.2.4 Constraints on Time-Bandwidth Product or Pulse Compression Ratio	16	(1)
2.2.5 Constraints on Doppler Resolution	16	(3)
2.2.6 Frequency Agility	19	(1)
2.2.7 PRI Agility	19	(4)
2.2.8 Power Constraints	23	(1)
2.2.9 Pulse Compression Modulation Constraints	23	(1)
2.3 Some ELINT Implications of Future Radar Designs	23	(3)
2.3.1 Bistatic and Multistatic Radars	24	(1)
2.3.2 Radar Trends	24	(2)
2.3.3 Wideband Active Adaptive Array Radars	26	(1)
2.4 Summary of Radar Design Constraints and Trends	26	(1)
2.5 High-Power Microwave Weapons	27	(1)
References	28	(1)
CHAPTER 3 Characteristics of ELINT Interception Systems	29	(68)
3.1 Intercept System Characteristics and Functions	29	(1)
3.2 Frequency Coverage	30	(1)
3.3 Analysis Bandwidth	31	(4)
3.3.1 Wideband Radar Signal Trends	33	(2)
3.4 Dynamic Range	35	(4)
3.4.1 Dynamic Range Requirements	37	(2)
3.5 Sensitivity	39	(13)
3.5.1 Noise Figure Measurement	40	(1)
3.5.2 Y-Factor Measurement	41	(2)
3.5.3 Some Sensitivity Measures	43	(1)
3.5.4 Output SNR and Receiver Applications	44	(1)
3.5.5 Threshold Detection	45	(6)
3.5.6 Sensitivity and the Received Pulse Density	51	(1)
3.6 The Ultimate Limits to ELINT Parameter Measurements	52	(4)
3.7 ECM and ELINT Receivers	56	(1)
3.8 Crystal Video Receivers	56	(7)
3.8.1 Crystal Video Applications	59	(1)
3.8.2 Postdetection Signal Recording and Sorting	60	(1)
3.8.3 CV System Design Considerations	60	(3)
3.9 Superheterodyne Receivers	63	(11)
3.9.1 Superhet Performance	65	(2)
3.9.2 Sweeping Superhet Receivers	67	(3)
3.9.3 Tuning Considerations	70	(2)
3.9.4 Other Heterodyne Receivers	72	(2)
3.10 Instantaneous Frequency Measurement Receivers	74	(11)
3.10.1 Limiters Applied to IFMs	74	(1)
3.10.2 The Simultaneous Signal Problem	75	(6)
3.10.3 CW Signals and IFMs	81	(1)
3.10.4 Digitizing the IFM Output	82	(3)
3.11 Other Receivers	85	(8)
3.11.1 Channelized Receivers	85	(4)
3.11.2 Acousto-Optic (Bragg Cell) Receivers	89	(1)
3.11.3 Microscan Receivers	90	(3)
3.12 System Considerations	93	(1)
References	94	(3)
CHAPTER 4 Probability of Intercept	97	(20)
4.1 Background	97	(1)
4.2 Developments in the Theory Behind POI	98	(16)
4.2.1 Intercept Description	98	(1)
4.2.2 Implications of Today's Environments/Operations on Intercept Time	98	(2)
4.2.3 Mathematical Models	100	(8)
4.2.4 Recent Developments on POI	108	(6)
4.3 Summary	114	(1)
References	114	(3)
CHAPTER 5 Antennas and Direction Finders	117	(32)
5.1 Omni-Directional Antennas	117	(4)
5.1.1 Omni-Directional Antenna Applications	117	(1)
5.1.2 Parameters for Omni-Directional Antennas	118	(3)
5.2 Directional Intercept Antennas	121	(3)
5.3 Direction Finding	124	(2)
5.4 Instantaneous Direction Finding	126	(18)
5.4.1 Amplitude Comparison AOA Measurement	127	(4)
5.4.2 Phase Interferometers	131	(8)
5.4.3 Bearing Discriminators	139	(5)
5.5 Arrays, Lenses, and Subspace DF Methods	144	(1)
5.6 Short Baseline TDOA for AOA	145	(2)
References	147	(2)
CHAPTER 6 Emitter Location	149	(20)
6.1 Introduction	149	(1)
6.2 Emitter Location Estimation	150	(2)
6.3 Deriving the Location Covariance Matrix	152	(1)
6.4 Angle of Arrival Location Analysis	153	(2)
6.5 Time Difference of Arrival Location Analysis	155	(4)
6.6 Time/Frequency Difference of Arrival Location Analysis	159	(4)
6.7 Geometric Dilution of Precision	163	(1)
6.8 Incorporation of Measurement Error	164	(3)
6.9 Summary	167	(1)
References	168	(1)
CHAPTER 7 Estimating Power at the Transmitter	169	(14)
7.1 Power Estimation Through ELINT	169	(1)
7.2 Distance to the Horizon	170	(1)
7.3 ERP Errors Due to Antenna Pointing Errors	171	(3)
7.4 Estimating the Distance to the Radar	174	(2)
7.5 Multiple Signal and Multipath Problems	176	(2)
7.6 Summary of Power Measurement Requirements	178	(1)
7.7 Sample ERP Calculations	179	(2)
References	181	(2)
CHAPTER 8 Antenna Parameters	183	(28)
8.1 Polarization Defined	183	(1)
8.2 Elliptical Polarization	183	(2)
8.3 Stokes' Parameters	185	(2)
8.4 Measuring Polarization	187	(4)
8.4.1 Polarization Pattern Method	188	(1)
8.4.2 Phase-Amplitude Method	189	(1)
8.4.3 Multiple Antenna Method	190	(1)
8.5 Cross-Polarization	191	(3)
8.6 Propagation Effects	194	(1)
8.7 System Aspects of Polarization	195	(1)
8.8 Antenna Beam Shape	196	(1)
8.9 Basic Antenna Pattern Relationships	197	(2)
8.10 Beam Patterns from FLINT	199	(6)
8.11 Beam Patterns of Array Antennas	205	(3)
8.12 Antenna Beam Summary	208	(1)
References	209	(2)
CHAPTER 9 LPI Radar and the Future of ELINT	211	(24)
9.1 What Is LPI Radar?	211	(1)
9.2 Radar and FLINT Detection of Signals	212	(1)
9.3 Matched Filter Theory	213	(1)
9.4 One Interception Strategy: Noncoherent Integration	213	(1)
9.5 ESM and Radar Range Compared	214	(3)
9.6 Some Pulse Compression Modulation Constraints	217	(1)
9.7 Interception Techniques Using the Envelope of the Received Signal	218	(9)
9.8 Narrowband Channels and Frequency Modulated Signals	227
9.9 Predetection Processing Methods to Detect Linear FM and Other LPI Signals	226	(6)
9.10 FLINT Receiver Requirements for Interception of Low Peak Power Signals	232	(1)
Reference	233	(2)
CHAPTER 10 Antenna Scan Analysis	235	(20)
10.1 Introduction	235	(1)
10.2 Some Principles of Searching	236	(1)
10.3 Relationships Among Scan Rate, Maximum Unambiguous Range, and Energy on Target	237	(2)
10.4 Fan Beam Scanning: Circular and Sector	239	(6)
10.5 Pencil Beam Scanning: Raster, Helical, and Spiral	245	(1)
10.6 Tracking Scans and Monopulse	246	(5)
10.7 Electronic Scanning	251	(1)
10.8 Scan Measurement and Analysis Techniques	252	(1)
10.9 A Three-Dimensional Search Example	253	(1)
References	254	(1)
CHAPTER 11 Intrapulse Analysis	255	(26)
11.1 Introduction	255	(2)
11.2 Pulse Envelope Parameters	257	(1)
11.3 Envelope Parameter Measurements	258	(6)
11.3.1 Rise and Fall Times	260	(4)
11.4 Some Radar Performance Limits Related to Pulse Envelope	264	(2)
11.5 Multipath Effects	266	(2)
11.6 Intrapulse Frequency and Phase Modulation	268	(4)
11.6.1 Choosing the Receiver Bandwidth	271	(1)
11.7 Intentionally Modulated Pulses	272	(3)
11.8 Incidental Intrapulse Shape—Uses and Causes	275	(3)
11.9 Comparing Wave Shapes	278	(2)
References	280	(1)
CHAPTER 12 Pulse Repetition Interval Analysis	281	(36)
12.1 Introduction	281	(1)
12.2 Common PRI Categories	282	(5)
12.2.1 Constant PRI	282	(2)
12.2.2 Jittered PRIs	284	(1)
12.2.3 Dwell and Switch PRI	285	(1)
12.2.4 PRI Stagger	285	(1)
12.2.5 Sliding PRIs	286	(1)
12.2.6 Scheduled PRIs	286	(1)
12.2.7 Periodic PRI Variations	287	(1)
12.2.8 Pulse Groups	287	(1)
12.3 Time Interval Measurements	287	(8)
12.3.1 SNR Limitations	288	(1)
12.3.2 Limitations Due to Pulse Amplitude Changes	289	(3)
12.3.3 Improving Interval Measurements	292	(2)
12.3.4 Digital Thresholding	294	(1)
12.4 PRI Analysis Techniques	295	(3)
12.4.1 Raster Displays	296	(1)
12.4.2 PRI Sounds	297	(1)
12.5 PRI Analysis Theory and Practice	298	(9)
12.5.1 Statistical Techniques	300	(3)
12.5.2 Delta-T Histogram	303	(4)
12.6 Interpreting the Results	307	(6)
12.6.1 Delay Line PRI Generators	308	(1)
12.6.2 Crystal Oscillators and Countdown Circuits	308	(5)
12.7 PRI and Range Velocity Ambiguities	313	(1)
12.8 MTI Radar Blind Speeds	313	(1)
12.9 Moving Target Detection	314
References	31	(286)
CHAPTER 13 Deinterleaving Pulse Trains	317	(18)
13.1 Pulse Sorting	317	(2)
13.2 PRI-Based Gating	319	(1)
13.3 Deinterleaving Algorithms	320	(2)
13.4 Delta-T Histogram Applied to Deinterleaving	322	(9)
13.5 The Pulse Train Spectrum	331	(1)
13.6 Combining Pulse Bursts	332	(1)
13.7 Raster Displays and Deinterleaving	333	(1)
13.8 Measuring Deinterleaver Performance	333	(1)
References	334	(1)
CHAPTER 14 Measurement and Analysis of Carrier Frequency	335	(32)
14.1 Pulsed Signal Carrier Frequency	335	(3)
14.1.1 Frequency Measurement Accuracies	335	(2)
14.1.2 Doppler Shifts	337	(1)
14.1.3 Drift Measurement	337	(1)
14.1.4 FM Ranging in Radar	338	(1)
14.2 Intrapulse Frequency or Phase Modulation	338	(4)
14.2.1 Analysis of Predetection Data	342	(1)
14.3 Coherence (Short-Term RF Stability)	342	(19)
14.3.1 RMS Phase Fluctuation	346	(1)
14.3.2 RMS Frequency Fluctuations	347	(3)
14.3.3 Signal Repeatability	350	(2)
14.3.4 Effects of Variations in τ0	352	(1)
14.3.5 Frequency-Domain Stability Measures	353	(1)
14.3.6 Bandwidth Limitations on Allan Variance Measurements	354	(2)
14.3.7 Noise Limitations on Allan Variance Measurements	356	(1)
14.3.8 Frequency Stability Measures for Power Law Spectra	357	(2)
14.3.9 Sinusoidal FM and Linear Frequency Drift	359	(1)
14.3.10 Short-Look Problem	359	(2)
14.4 Frequency Character of CW Signals	361	(1)
14.5 Pulsed Signal Example	361	(3)
14.6 Measuring Coherence	364	(1)
14.7 Effects of Drift	365	(1)
References	365	(2)
CHAPTER 15 Determining ELINT Parameter Limits	367	(16)
15.1 Introduction	367	(1)
15.2 Histograms Used to Determine Parameter Limits	367	(3)
15.3 Types of Histograms	370	(3)
15.4 Two-Sigma Parameter Limits	373	(2)
15.5 Histogram Analysis Techniques	375	(4)
15.5.1 Parameter Limits Example	375	(2)
15.5.2 Intercepts Separated into Accuracy Classes	377	(1)
15.5.3 Most Probable Values	378	(1)
15.6 Analysis Problems	379	(2)
15.6.1 Signal Identification Errors	379	(1)
15.6.2 Transforming Parameters and Their Accuracies	379	(2)
15.7 Histogram Analysis Summary	381	(1)
References	382	(1)
CHAPTER 16 ELI NT Data Files	383	(8)
16.1 Introduction	383	(2)
16.2 Signal Identification	385	(1)
16.3 ELINT Data for Radar Warning Receiver Design	386	(2)
16.4 ELINT Data for Simulation and Training	388	(1)
16.5 Adding Non-ELINT Data	388	(1)
16.6 Summary	389	(1)
Reference	389	(2)
APPENDIX A Spectrum Widths: 3-dB and First Nulls for Trapezoidal Pulses	391	(4)
A.1 Introduction	391	(1)
A.2 Rectangular Pulses	391	(1)
A.3 Trapezoidal Pulses: Equal Rise and Fall Times	391	(2)
A.4 Trapezoidal Pulses: Unequal Rise and Fall Times	393	(2)
APPENDIX B Some ELINT Considerations of FM Signals	395	(18)
B.1 Introduction	395	(1)
B.2 Effects of Sinusoidal Interference on Phase- and Frequency-Demodulated Signals	395	(3)
B.3 Signals with Sinusoidal Frequency Modulation	398	(2)
B.4 Carson's Rule	400	(1)
B.5 Modification of Carson's Rule for ELINT Applications	401	(2)
B.6 FM Demodulation Degradation by RF Band Limiting	403	(5)
B.7 Effects of Noise on FM Demodulated Signals	408	(4)
References	412	(1)
APPENDIX C A Frequency Hop Radar Example	413	(16)
C.1 Probability That One or More Pulses Occur at the Desired Frequency	413	(1)
C.2 Probability That Exactly One Pulse Occurs at the Desired Frequency	414	(1)
C.3 Probability That Exactly k Pulses Occur at the Desired Frequency	415	(1)
C.4 Probability That Several Pulses Occur at the Desired Frequency Less Than G Pulses Apart	415	(3)
C.5 Probability Distribution of the Interval Between Two Pulses	418	(9)
C.6 Determining an Optimum Receiver Sweep Rate	427	(2)
APPENDIX D History and Fundamentals of the IFM	429	(12)
D.1 The Broadband Microwave Frequency Discriminator	433	(6)
References	439	(2)
APPENDIX E Emitter Location Partial Derivatives	441	(4)
About the Author	445	(2)
Index	447