Which technique is commonly used to mitigate radar clutter on ATC displays?

• A. Redundant hardware layout
• B. Moving Target Indication (MTI)
• C. Manual data entry
• D. Peak detection

Answer: (B)

Clutter suppression on radar displays relies on distinguishing moving objects from stationary ones. Moving Target Indication uses the Doppler effect to do this: it compares successive radar echoes and cancels out returns with little or no Doppler shift, which are typical of stationary clutter like the ground or fixed objects. By removing these static echoes, moving aircraft stand out more clearly on the ATC display, making tracking easier and faster.

In practice, an MTI system applies a high-pass filter in the Doppler domain, effectively locking onto targets that are changing range or speed from pulse to pulse. This reduces ground clutter and other stationary reflections while preserving the echoes from moving aircraft. Some limitations exist, such as slow-moving targets or certain weather returns being partially suppressed or misidentified, but MTI remains the most common method for reducing clutter on ATC radars.

Other options don’t fit this purpose as directly: redundant hardware layout improves reliability, not clutter removal; manual data entry is unrelated to automatic clutter suppression; peak detection is a general signal-processing step that doesn’t specifically filter out stationary clutter on the display.