Primary Surveillance Radar: interactive

Point the beam Visible

Range 60 NM Target

Ready
Press “Transmit pulse”. The animation is slowed down roughly a million times so you can see it.

Aerial is pointing

000°

Last return painted

Waiting for the sweep

Rings every 10 NM, out to 60 NM. Amber is energy going out; cyan is energy coming back.

Beam width 3° Gap between aircraft 7° Two targets

Aerial site

Aircraft height Painted

Painted on the displayNot seen

Illustrative only. The lobe shapes are simplified and the height scale is exaggerated.

Aircraft altitude Painted

Painted on the displayNot seenShadow (fade area)

Altitude 30,000 ft Painted

The blind cone is drawn to match the book’s example (about 20 NM at 30,000 ft). Real sizes vary by site, aerial design and tilt.

Range 50 NM Altitude 3,500 ft

Target not detected

Aircraft A, flying straight towards the radar

300 kt towards

Aircraft B, crossing the radar’s line of sight

0 kt

Passing distance 14 NM Groundspeed 300 kt

Radial speed0 kt

Tangential speed0 kt

Fade length on this track0 NM

Painted

Aircraft velocityRadial part (Doppler sees this)Tangential part (invisible to Doppler)Filtered out

Illustrative only. Filter threshold set at 50 kt radial speed; real MTI and MTD settings vary by system.

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