Frequency ambiguity resolution
ambiguous velocityFrequency ambiguity resolution detailed explanationFrequency ambiguity resolution process explanation
Frequency ambiguity resolution is used to find true target velocity for medium pulse repetition frequency (PRF) radar systems.wikipedia
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This is used with pulse-Doppler radar.
* Frequency ambiguity resolution detailed explanation
PRFpulse repetition frequenciesmedium pulse repetition frequency
Frequency ambiguity resolution is used to find true target velocity for medium pulse repetition frequency (PRF) radar systems.
For example, an L-Band radar with 500 Hz pulse rate produces ambiguous velocity above 75 m/s (170 mile/hour), while detecting true range up to 300 km. This combination is appropriate for civilian aircraft radar and weather radar.
Radar pulsing causes a phenomenon called aliasing, which occurs when the Doppler frequency created by reflector motion exceeds the pulse repetition frequency (PRF).
Nyquist limitNyquist sampling rateNyquist
This limitation is called the Nyquist sampling rate.
NyquistN/2 different frequenciesNyquist component
Frequency is folded for high speed targets where radial velocity produces a frequency shift above the Nyquist frequency.
The true speed of the target may be folded by a modulo operation produced by the sampling process.
This could also be implemented as a convolution function, where the spectrum amplitudes from one PRF are applied to spectrum samples from the other PRF as a sliding window function.
Doppler CFAR detection processingPulse-Doppler signal processing detailed explanation
* Frequency ambiguity resolution process explanation
Ambiguity resolution detailed explanationAmbiguity resolution process explanation
The received signals are also compared using the frequency ambiguity resolution process.