CFAR stands for Constant False Alarm Rate. What is its primary purpose?

• A. CFAR increases transmitter power to reduce false alarms
• B. CFAR is used to filter out all noise without affecting clutter
• C. CFAR is a video display enhancement
• D. CFAR stands for Constant False Alarm Rate; it adaptively sets detection thresholds

Answer: (D)

CFAR’s main idea is to keep the detector’s false alarms steady even when the clutter environment changes. In radar, a fixed threshold would produce many false alarms if the background clutter rises, or miss targets if it falls. CFAR addresses this by estimating the local noise or clutter level from surrounding cells and adjusting the detection threshold accordingly. This adaptive thresholding keeps the probability of false alarms roughly constant while maintaining good target detection.

The other options don’t fit because increasing transmitter power doesn’t control false alarms from clutter, filtering all noise without affecting clutter isn’t feasible or desirable, and CFAR isn’t a video display feature.