Radar countermeasure

Radar jamming and deception (electronic countermeasures) is the intentional emission of radio frequency signals to interfere with the operation of a radar by saturating its receiver with noise or false information. There are two types of radar jamming: Mechanical and Electronic jamming.

Mechanical jamming is caused by devices which reflect or re-reflect radar energy back to the radar to produce false target returns on the operator's scope. Mechanical jamming devices include chaff, corner reflectors, and decoys.

Electronic jamming is a form of electronic warfare where jammers radiate interfering signals toward an enemy's radar, blocking the receiver with highly concentrated energy signals. The two main technique styles are noise techniques and repeater techniques. The three types of noise jamming are spot, sweep, and barrage.

Protective/Standoff jamming

Protective/Escort jamming

The burn-through range is the distance from the radar at which the jamming is ineffective. When a target is within this range, the radar receives an adequate target skin return to track it. The burn through range is a function of the target RCS (Radar cross-section), jamming ERP (Effective radiated power), the radars ERP and required J/S (for the jamming to be effective).

In some cases, jamming of either type may be caused by friendly sources. Inadvertent mechanical jamming is fairly common because it is indiscriminate and will affect any nearby radars, hostile or not. Electronic jamming can also be inadvertently caused by friendly sources, usually powerful EW platforms operating within range of the affected radar. Unintentional electronic jamming is most easily prevented by good planning and common sense, though sometimes it is unavoidable.

An anti-drone equipment was used at the 2018 Commonwealth Games in Gold Coast in April. The 'Anti-drone gun' is a non-lethal weapon used by Queensland Police Service to safely detect, and disrupt unauthorised drone activity in high-security areas of the event.
The DroneShield DroneGun MKII works by intercepting the signal between a person holding the drone controller and the drone, disabling video transmission from a camera on the drone, and allowing the anti-drone controller to safely bring the drone to the ground.

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