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