How does PRF staggering help resolve range/velocity ambiguities?

• A. Using a single fixed PRF simplifies processing.
• B. PRF staggering eliminates all ambiguities instantly.
• C. Using different PRFs in successive scans allows comparison to disambiguate range and velocity values.
• D. PRF staggering increases the radar range.

Answer: (C)

PRF staggering works by transmitting with different pulse repetition frequencies across successive scans, giving multiple independent views of the same target’s range and Doppler. The unambiguous range for a given PRF is c/(2·PRF). With a fixed PRF, targets beyond that limit wrap around, causing range ambiguity; changing to another PRF shifts where that wrap occurs. Similarly, Doppler measurements are aliased according to the PRF, so velocity appears ambiguous as well. By comparing the range and Doppler measurements obtained with several different PRFs, you can find the true range and true velocity that fit all the observations. This cross-check across PRFs resolves the ambiguities that a single PRF would produce.