Radar jamming and deception

• 
  Protective/Standoff jamming
• 
  Protective/Escort jamming

Noise jamming

${\displaystyle {\frac {J}{S}}={\frac {EIRP_{jam}}{EIRP_{radar}}}\times {\frac {4\pi R^{2}}{\sigma }}\times {\frac {BW_{radar}}{BW_{jam}}}}$.^[3]

Radar burn-through

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 (

• Constantly alternating the frequency that the radar operates on (
  spread-spectrum
  will limit the effectiveness of most jamming, making it easier to read through it. Modern jammers can track a predictable frequency change, so the more random the frequency change, the more likely it is to counter the jammer.
• Cloaking the outgoing signal with random noise makes it more difficult for a jammer to figure out the frequency that a radar is operating on.
• Limiting unsecure radio communication concerning the jamming and its effectiveness is also important. The jammer could be listening, and if they know that a certain technique is effective, they could direct more jamming assets to employ this method.
• The most important method to counter radar jammers is operator training. Any system can be fooled with a jamming signal but a properly trained operator pays attention to the raw video signal and can detect abnormal patterns on the radar screen.
• The best indicator of jamming effectiveness to the jammer is countermeasures taken by the operator. The jammer does not know if their jamming is effective before operator starts changing radar transmission settings.
• Using EW countermeasures will give away radar capabilities thus on peacetime operations most military radars are used on fixed frequencies, at minimal power levels and with blocked
  Tx
  sectors toward possible listeners (country borders).
• Mobile
  fire control radars
  are usually kept passive when military operations are not ongoing to keep radar locations secret.
• low probability of intercept
  (LPI) modes to reduce the chance that the radar is detected.
• A quantum radar system would automatically detect attempts at deceptive jamming, which might otherwise go unnoticed.^[4]
• Anti-radiation missile (ARM) also known as Home-On-Jam (HOJ) missiles: When a target is using self-protective jamming (SPJ), it essentially broadcasts its position. An ARM could be deployed and take out the jamming source. The missile utilizes passive RF homing which reduces its probability of detection. A countermeasure to ARM is not to use self-protective jamming (one could use stand-off jamming, assuming that the missiles has a range no longer than the radar), or have a decoy taking the missile (such as ADM-160 MALD and AN/ALE-55 Fiber-Optic Towed Decoy). By towing a decoy/jammer, the decoy maintains a realistic Doppler shift (which tricks the tracker) and lures an ARM away from the target.

Stealth

For protective jamming, a small radar cross section of the protected aircraft will improve the jamming efficiency (higher J/S).^{[citation needed]} A lower RCS also reduces the "burn-through" range. Stealth technologies like

While not usually caused by the enemy, interference can greatly impede the ability of an operator to track. Interference occurs when two radars in relatively close proximity (how close they need to be depends on the power of the radars) are operating on the same frequency. This will cause "running rabbits", a visual phenomenon that can severely clutter up a radar display scope with useless data. Interference is not that common between ground radars, however, because they are not usually placed close enough together. It is more likely that some sort of airborne radar system is inadvertently causing the interference—especially when two or more countries are involved.

The interference between airborne radars referred to above can sometimes (usually) be eliminated by frequency-shifting transmitters.

The other interference often experienced is between the aircraft's own electronic transmitters, i.e. transponders, being picked up by its radar. This interference is eliminated by suppressing the radar's reception for the duration of the transponder's transmission. Instead of "bright-light" rabbits across the display, one would observe very small black dots. Because the external radar causing the transponder to respond is generally not synchronised with your own radar (i.e. different PRFs [pulse repetition frequency]), these black dots appear randomly across the display and the operator sees through and around them. The returning image may be much larger than the "dot" or "hole", as it has become known, anyway. Keeping the transponder's pulse widths very narrow and mode of operation (single pulse rather than multi-pulse) becomes a crucial factor.

The external radar could, in theory, come from an aircraft flying alongside your own, or from space. Another factor often overlooked is to reduce the sensitivity of one's own transponder to external radars; i.e., ensure that the transponder's threshold is high. In this way it will only respond to nearby radars—which, after all, should be friendly.

One should also reduce the power output of the transponder in like manner.

Jamming police radar

Jamming radar for the purpose of defeating police

• 36th Bombardment Squadron
   – military unitPages displaying wikidata descriptions as a fallback
• Active electronically scanned array – Type of phased array radar
• AN/ALE-55 Fiber-Optic Towed Decoy – Countermeasure from radar guided missiles
• Association of Old Crows – Electronic warfare professional organization
• Echolocation jamming – Interference with animal sonar systems
• Electronic attack
   – Electronic device for deceiving detection systemsPages displaying short descriptions of redirect targets
• Electronic warfare
   – Combat involving electronics and directed energyPages displaying short descriptions of redirect targets
• Infrared countermeasure – Device designed to protect aircraft from infrared homing missiles
• Low-probability-of-intercept radar – Radar technology that hides its activity from a detected target
• No. 100 Group RAF – Former Royal Air Force operations group
• Pelena-1 – Russian ground-based jamming system
• Radio jamming – Interference with authorized wireless communications
• Suppression of Enemy Air Defenses – Military tactic

References