EW 105: SPACE ELECTRONIC WARFARE
CONTENTS
PREFACE
1
INTRODUCTION
1.1 ORBITAL RELATIONSHIPS
1.2 BOOK FLOW
1.3 HISTORY OF SIGNAL INTELLIGENCE SATELLITE PROGRAMS
1.4 A NOTE ABOUT ORBITAL CALCULATIONS IN THIS BOOK
2
SPHERICAL TRIGONOMETRY
2.1 PLANE TRIGONOMETRY
2.1.1 The Law of Sines
2.1.2 The Law of Cosines for Sides
2.1.3 The Law of Cosines for Angles
2.1.4 Right Plane Triangle
2.2 THE SPHERICAL TRIANGLE
2.3 TRIGONOMETRIC RELATIONSHIPS IN ANY SPHERICAL TRIANGLE
2.3.1 Law of Sines for Spherical Triangles
2.3.2 Law of Cosines for Sides
2.3.3 Law of Cosines for Angles
2.3.4 The Right Spherical Triangle
2.3.5 Napierβs Rules
2.4 EXAMPLES OF PLANE AND SPHERICAL TRIANGLES USED IN PROBLEMS
3
ORBIT MECHANICS
3.1 ELEMENTS OF AN ELLIPTICAL ORBIT
3.2 RELATIONSHIP BETWEEN THE SIZE OF AND ITS PERIOD
3.3 SVP
3.4 AN EARTH SURFACE LOCATION
3.5 THE PROPAGATION DISTANCE
3.6 EARTH TRACES
3.6.1 Satellite Earth Trace
3.6.2 Polar Orbit Earth Traces
3.6.3 Synchronous Satellite Earth Traces
3.7 LOCATION OF AN EW THREAT
3.7.1 Calculating the Look Angles
3.7.2 Calculating the Azimuth to the Threat
3.7.3 Calculating Range and Elevation to the Threat Location
3.8 CALCULATING THE DISTANCE TO THE HORIZON
3.8.1 Horizon Distances for Circular Orbits
4
RADIO PROPAGATION
4.1 INTRODUCTION
4.2 ONE-WAY LINK
4.3 PROPAGATION LOSS MODELS
4.3.1 LOS Propagation
4.3.2 Two-Ray Propagation
4.3.3 Minimum Antenna Height for Two-Ray Propagation
4.3.4 A Note about Very Low Antennas
4.3.5 Fresnel Zone
4.3.6 Complex Reflection Environment
4.3.7 KED
4.3.8 Atmospheric Loss
4.3.9 Rain and Fog Attenuation
5
RADIO PROPAGATION IN SPACE
5.1 LOS LOSS
5.1.1 Atmospheric Loss
5.2 ANTENNA MISALIGNMENT
5.3 POLARIZATION LOSS
5.4 RAIN LOSS
6
SATELLITE LINKS
6.1 LINK GEOMETRY
6.1.1 Looking Down
6.1.2 Plug in Some Orbit Numbers
6.1.3 Looking Up
6.2 UPLINKS
6.2.1 Command Links
6.2.2 Intercept Links
6.3 DOWNLINKS
6.3.1 Telemetry Link
6.3.2 Data Link
6.3.3 Links to Data Users
6.3.4 Jamming Links
6.4 HOSTILE LINKS
7
LINK VULNERABILITY TO EW
7.1 SATELLITE VULNERABILITY
7.1.1 Space-Related Link Losses
7.1.2 Intercept
7.1.3 Spoofing
7.1.4 Jamming
7.1.5 Problems Worked in This Chapter
7.2 DOWNLINK INTERCEPT
7.2.1 Geocentric Angle from the Satellite to the Intercept Site
7.2.2 Range from the Satellite to the Intercept Site
7.2.3 Is the Satellite Above the Horizon from the Intercept Site?
7.2.4 How Strong Is the Downlink Signal at the Intercept Site
7.2.5 Intercept with Directional Antennas
7.2.6 Angles Relative to the Ground Control Station
7.2.7 Angles Relative to the Hostile Intercept Site
7.2.8 Received Signal at the Intercept Site
7.2.9 What Is the Quality of the Intercept Signal?
7.3 INTERCEPTING UPLINKS
7.4 JAMMING DOWNLINKS
7.4.1 The Satellite Downlink
7.4.2 The Jammer Link
7.4.3 The J/S Formula
7.5 JAMMING SATELLITE UPLINKS
7.5.1 The Jamming Link
7.5.2 Jamming Link Loss
7.5.3 Gain of 4-m Jamming Antenna at 5 GHz
7.5.4 Jammer ERP
7.5.5 The Satellite Uplink
7.5.6 Gain of 2-m Uplink Transmitter Antenna
7.5.7 Uplink ERP
7.5.8 Uplink Loss
7.5.9 Gain and Bandwidth of the Uplink Reciving Antenna on the Satellite
7.5.10 Antenna 3-dB Beamwidth
7.5.11 Offset of the Jammer from the Downlink Receiving Antenna
7.5.12 The J/S
7.6 ELECTRONIC PROTECTION OF SATELLITE LINKS
7.6.1 Attacks on Links
7.6.2 Protection Against Jamming
8
DURATION AND FREQUENCY OF OBSERVATIONS
8.1 CALCULATING THE DISTANCE TO THE HORIZON
8.2 HORIZON DISTANCES FOR CIRCULAR ORBITS
8.3 CALCULATING THE DURATION OF TARGET AVAILABILITY FROM A SATELLITE
8.3.1 Geocentric Viewing Angle
8.3.2 Time During Which a Satellite Can See a Point on the Earth
8.3.3 The Impact of the Movement of the Earth
8.3.4 Viewing Time Formula
8.4 DOPPLER SHIFT IN SATELLITE LINK
8.4.1 Doppler Shift Formula
8.4.2 Receiving Site Velocity
8.4.3 Satellite Velocity
8.4.4 General Formula for Maximum Doppler Shift
8.4.5 General Formula for the Doppler Shift
9
INTERCEPT FROM SPACE
9.1 INTERCEPT OF RADAR SIGNAL FROM LOW-EARTH SATELLITE
9.1.1 Link Loss
9.1.2 LOS Loss
9.1.3 Atmospheric and Rain Loss
9.1.4 Can the Satellite Payload Receive the Signal?
9.1.5 Receiver Sensitivity
9.1.6 Link Margin
9.1.7 Could the Satellite Receive the Signal from Its Horizon?
9.1.8 How Long Will the Satellite See the Signal?
9.2 HORIZON PLOT ON THE EARTH
9.3 INTERCEPT OF THE EARTH SURFACE TARGET USING A NARROW-BEAM RECEIVING ANTENNA
9.3.1 Antenna Pointing
9.3.2 Intercept Link Equation
9.3.3 Link Losses
9.3.4 Intercept from the Horizon
9.4 INTERCEPT FROM THE SYNCHRONOUS SATELLITE
9.4.1 With the Satellite on the Horizon
9.4.2 With the Satellite Directly Overhead
10
JAMMING FROM SPACE
10.1 JAMMING OF A GROUND SIGNAL FROM A SATELLITE
10.2 JAMMING FROM A SATELLITE
10.3 JAMMING OF A COMMUNICATIONS NETWORK
10.3.1 The Network
10.3.2 Link Equations
10.3.3 J/S
10.4 JAMMING A MICROWAVE DIGITAL DATA LINK
10.5 JAMMING OF A GROUND RADAR FROM SPACE
10.5.1 Radar Jamming from a Satellite
10.5.2 The Jammed Radar and Its Target
10.5.3 The Jammer
10.5.4 The Jamming Equation
10.5.5 The Jamming Adequacy
10.5.6 Protecting an Asset with Low Radar Cross-Section
10.5.7 Duration of Jamming
A FORMULAS FROM SIGNAL INTELLIGENCE AND EW
A.1 INTERCEPT FORMULAS
A.1.1 Successful Intercept
A.1.2 The Intercept Link Equation
A.1.3 Received Signal Quality
A.2 COMMUNICATION JAMMING
A.2.1 Successful Communications Jamming
A.2.2 Communications J/S
A.2.3 Communications EP
A.3 RADAR JAMMING
A.3.1 Successful Radar Jamming
A.3.2 Self-Protection Jamming
A.3.3 Stand-Off Jamming
A.3.4 Required J/S
A.3.5 Radar EP
B
IMPORTANT NUMBERS FOR SPACE EW
C
DECIBEL MATH
C.1 DECIBEL NUMBERS
C.2 CONVERSION TO DECIBEL FORM
C.3 ABSOLUTE VALUES IN DECIBEL FORM
C.4 DECIBEL FORMS OF EQUATIONS
C.5 QUICK CONVERSIONS TO DECIBEL VALUES
BIBLIOGRAPHY
ABOUT THE AUTHOR
INDEX