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Electronic Attack – Radar
Short Course on Radar and Electronic Warfare
Kyle Davidson
Non-adaptive jammers
DDS – Waveform Generation
Transponder Jammers
WaveGeneration
Receiver
DSP/DRFM
Repeater Jammer
Modulation
Receiver
Classes of Noise Jamming
• Barrage
• Narrow band
• Partial band
• Tone Jamming
• Swept Jamming
• Pulse Jamming
• Inverse Power Jamming
• Follower Jamming
Barrage Jamming
Partial Band Jamming
Pilsed Jamming
Tone Jamming
Follower Jammer Reaction Time
• Need to be in the elipsedefined by:
𝐷𝑇𝐽 + 𝐷𝐽𝑅𝑐
+ 𝑇𝑗 ≤𝐷𝑇𝑅
𝑐+ 𝛾𝑇𝑑
• 𝑇𝑑 is the dwell time
• 𝑇𝑗 is the processing time of the jammer
• 𝛾 is a fraction
Noise Jamming Effects
Effects of Frequency Hopping
Inverse Power Jamming
Jammer Scenario
Jammer to Signal Ratio
• Power received in a radar from the target
𝑃𝑟 =𝑃𝑡𝐺𝑡𝐺𝑟𝜆
2𝜎
4𝜋 3𝑅4
• Power received from the jammer
𝑃𝑟𝑗 =𝑃𝑗𝐺𝑗𝐺𝑡𝑗𝜆
2
4𝜋 2𝑅2
• Jammer to signal ratio𝐽
𝑆=𝑃𝑗𝐺𝑗
𝑃𝑡𝐺𝑡
4𝜋𝑅2
𝜎
The Bistatic Case
• Fro the bistatic case, we can use a similar method to develop the jammer to signal ratio:
𝐽
𝑆=𝑃𝑗𝐺𝑗𝐺𝑟𝑗𝜆
2
4𝜋 2𝑅𝑗2
4𝜋 3𝑅𝑡𝑅𝑟𝑃𝑡𝐺𝑡𝐺𝑅𝜆
2𝜎𝑏𝑖𝑠𝑡𝑎𝑡𝑖𝑐
• This reduces to:
𝐽
𝑆=𝑃𝑗𝐺𝑗𝐺𝑟𝑗𝑃𝑡𝐺𝑡𝐺𝑟
4𝜋𝑅𝑡2𝑅𝑟
2
𝑅𝑗𝜎𝑏𝑖𝑠𝑡𝑎𝑡𝑖𝑐
Probability of Detection
Choosing a Threshold
Distribution Curve
Signal and Jamming Distributions
What is the effect?
Receiver Operating Curve
Range Deception
Deception and Frequency Hopping
Towed Decoys
Deception Jamming
• Range Gate Pull Off
• Velocity Gate Pull Off
• Cross–eye jamming
• Cross-polarization jamming
Cross-eye Jamming
• Antenna Align with Phase Fronts
• Cross-eye Jammers Screw with the Phase Front