Which filter inhibits processing and display of certain clutter returns (such as close-in vehicle traffic)?

• A. LIF - Light Interference Filter
• B. GREF - Ground Reflection Filter
• C. GLIF - Ground Level Interference Filter
• D. CLIF - Close-in Interference Filter

Answer: (C)

Ground level clutter suppression is the idea here: you want the radar to ignore returns that come from the ground or near-ground clutter, so you don’t display false targets like close-in vehicle traffic. The Ground Level Interference Filter is designed to suppress these low-elevation, near-ground clutter returns, which lets the system process and display real targets at higher elevations or farther ranges without being overwhelmed by ground-based noise.

The other filters don’t target this specific issue as effectively. A Light Interference Filter isn’t about radar clutter at all, so it wouldn’t address ground clutter. A Ground Reflection Filter would deal with ground reflections generally, but it doesn’t specifically focus on the close-in clutter problem. A Close-in Interference Filter would suppress interference close to the radar, but it risks discarding legitimate nearby targets; the Ground Level Interference Filter is the specialized choice for removing close-in ground clutter like vehicle traffic.