Doppler resolution and MTI performance: what is it?

• A. Doppler resolution measures the range precision of a radar oscillator.
• B. Doppler resolution is the angular resolution of the radar.
• C. Doppler resolution is the smallest velocity difference detectable; higher resolution improves MTI's ability to separate close velocity targets and suppress clutter.
• D. Doppler resolution describes the maximum detectable velocity before aliasing.

Answer: (C)

The main idea here is that Doppler resolution is about how finely you can separate moving targets by their velocity in Doppler processing. In MTI, you rely on differences in Doppler frequency to distinguish moving targets from stationary clutter. When the Doppler bin width is small, you can separate targets whose velocities are very close together, which lets MTI suppress clutter more effectively and keep real moving targets cleanly detected.

In practical terms, Doppler resolution improves as you increase the coherent processing interval (more pulses) because the Doppler frequency bins become narrower. Since Doppler frequency shifts relate to velocity by fd = 2v/λ, the smallest detectable velocity difference is Δv = (λ/2) Δfd. So a longer processing time (narrower Δfd) gives a smaller Δv, i.e., finer velocity resolution, which enhances MTI performance by better separating close-velocity targets and reducing clutter leakage.

The other options describe range precision, angular resolution, or maximum unambiguous velocity—concepts that are not what Doppler resolution measures.