How do Range-Doppler processing and time-domain pulse detection differ in radar signal processing?

How do Range-Doppler processing and time-domain pulse detection differ in radar signal processing?

• A. Range-Doppler uses FFT across slow-time to form a 2D range-Doppler map; time-domain uses matched-filtering on fast-time.
• B. Range-Doppler uses matched-filtering on fast-time; time-domain uses FFT across slow-time.
• C. Range-Doppler is for range estimation only; time-domain is for Doppler.
• D. Range-Doppler uses time-domain sampling; time-domain uses frequency-domain.

Answer: (B)

The main idea is how range and Doppler (velocity) information are extracted from the echoes. In range-Doppler processing, you first resolve range within each received pulse by sampling in fast-time and applying a pulse-compression filter (a matched filter or similar) to produce a clear range profile. Then you look at how those echoes change from pulse to pulse by taking a Fourier transform across slow-time (the sequence of pulses) for each range bin. That FFT across slow-time yields Doppler information, and combining the range information with the Doppler results gives a two-dimensional range-Doppler map. Time-domain pulse detection, on the other hand, stays in the time domain for each pulse. It relies on detecting the presence of the echo by correlating the received fast-time waveform with the transmitted pulse (matched-filtering in fast-time) to detect range, but it does not form the Doppler dimension by transforming across pulses. Doppler information, if extracted at all in that approach, would come from separate analysis across pulses, not from a core time-domain per-pulse detection. So the best understanding is: Range-Doppler processing uses pulse compression in fast-time and FFT across slow-time to build a 2D range-Doppler map, while time-domain pulse detection focuses on detecting echoes within each pulse via matched-filtering in fast-time.

The main idea is how range and Doppler (velocity) information are extracted from the echoes. In range-Doppler processing, you first resolve range within each received pulse by sampling in fast-time and applying a pulse-compression filter (a matched filter or similar) to produce a clear range profile. Then you look at how those echoes change from pulse to pulse by taking a Fourier transform across slow-time (the sequence of pulses) for each range bin. That FFT across slow-time yields Doppler information, and combining the range information with the Doppler results gives a two-dimensional range-Doppler map.

Time-domain pulse detection, on the other hand, stays in the time domain for each pulse. It relies on detecting the presence of the echo by correlating the received fast-time waveform with the transmitted pulse (matched-filtering in fast-time) to detect range, but it does not form the Doppler dimension by transforming across pulses. Doppler information, if extracted at all in that approach, would come from separate analysis across pulses, not from a core time-domain per-pulse detection.

So the best understanding is: Range-Doppler processing uses pulse compression in fast-time and FFT across slow-time to build a 2D range-Doppler map, while time-domain pulse detection focuses on detecting echoes within each pulse via matched-filtering in fast-time.