What is a range gate and how is it used in target detection?

• A. A range gate is a mechanical gate used to protect the antenna
• B. A range gate is a time window corresponding to a range bin; used to accept returns within that window and reject others
• C. A range gate is a filter for Doppler frequency
• D. A range gate is the distance to the target

Answer: (B)

A range gate is a time window tied to a specific range bin; the radar opens the receiver during the interval when an echo from that range would arrive after a transmitted pulse. Echoes that fall inside this window are kept and processed as potential targets, while signals outside are discarded. This gating focuses the detection on a particular distance, improving signal-to-noise by rejecting clutter and noise from other ranges. The gate width relates to the range resolution, so you can adjust how precisely you’re looking at distance. It’s a signal-processing concept, not a physical barrier, and it’s distinct from Doppler filtering (which separates targets by velocity) or simply reporting the distance to a target.