Which radar method works well for stationary objects?

Which radar method works well for stationary objects?

• A. Pulse Modulation
• B. Frequency Modulation
• C. Continuous Wave (CW)
• D. Pulse Doppler

Answer: (B)

FMCW (frequency-modulated continuous-wave) radar is especially good for measuring distance to targets that aren’t moving. The transmitter sweeps its frequency over a wide band, and the target’s return is mixed with the transmitted signal to produce a beat frequency. That beat frequency is directly related to how long the signal took to travel to the target and back, so you can compute range without relying on any Doppler shift from motion. The crucial point is that distance information comes from the known frequency sweep and the resulting beat note, not from how fast the target is moving. Because the measurement depends on the difference in timing (range) rather than velocity, stationary targets still produce a clear range indication. The range resolution improves with larger sweep bandwidth—the wider the frequency sweep, the finer the detail you can distinguish in distance. In contrast, a pure CW radar only gives velocity information via Doppler shift and can’t determine range, while pulsed or Pulse Doppler systems rely on motion to separate targets and may struggle with stationary clutter; FMCW avoids those limitations by encoding range directly into the beat frequency from the frequency sweep.

FMCW (frequency-modulated continuous-wave) radar is especially good for measuring distance to targets that aren’t moving. The transmitter sweeps its frequency over a wide band, and the target’s return is mixed with the transmitted signal to produce a beat frequency. That beat frequency is directly related to how long the signal took to travel to the target and back, so you can compute range without relying on any Doppler shift from motion. The crucial point is that distance information comes from the known frequency sweep and the resulting beat note, not from how fast the target is moving.

Because the measurement depends on the difference in timing (range) rather than velocity, stationary targets still produce a clear range indication. The range resolution improves with larger sweep bandwidth—the wider the frequency sweep, the finer the detail you can distinguish in distance. In contrast, a pure CW radar only gives velocity information via Doppler shift and can’t determine range, while pulsed or Pulse Doppler systems rely on motion to separate targets and may struggle with stationary clutter; FMCW avoids those limitations by encoding range directly into the beat frequency from the frequency sweep.