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PRF is crucial for systems and devices that measure distance. Radar; Laser range finder; Sonar; Different PRF allow systems to perform very different functions. A radar system uses a radio frequency electromagnetic signal reflected from a target to determine information about that target. PRF is required for radar operation. This is the rate at ...
A pulse-Doppler radar is a radar system that determines the range to a target using pulse-timing techniques, and uses the Doppler effect of the returned signal to determine the target object's velocity.
When the PRF of the "jamming" radar is very similar to "our" radar, those apparent distances may be very slow-changing, just like real targets. By using stagger, a radar designer can force the "jamming" to jump around erratically in apparent range, inhibiting integration and reducing or even suppressing its impact on true target detection.
Each individual PRF has blind ranges, where the transmitter pulse occurs at the same time as the target reflection signal arrives back at the radar. Each individual PRF has blind velocities where the velocity of the aircraft will appear stationary. This causes scalloping, where the radar can be blind for some combinations of speed and distance.
Doppler frequency provides an additional feedback signal similar to the feedback used in a phase-locked loop. This improves the accuracy and reliability of the position and velocity information. The amplitude and phase for the signal returned by the reflector is processed using monopulse radar techniques during track. This measures the offset ...
Because of the low pulse repetition frequency (PRF) of most coherent pulsed radars, which maximizes the coverage in range, the amount of Doppler processing is limited. The Doppler processor can only process velocities up to ± 1 / 2 the PRF of the radar. This is not a problem for weather radars.
Radar pulsing causes a phenomenon called aliasing, which occurs when the Doppler frequency created by reflector motion exceeds the pulse repetition frequency (PRF). [1] This concept is related to range ambiguity resolution. Doppler frequency shift is introduced onto reflected signals used by radar.
This happens with all radar systems. [1] Radar aliasing happens when: Pulse repetition frequency (PRF) is too low to sample Doppler frequency directly; PRF is too high to sample range directly; Pulse Doppler sonar uses similar principles to measure position and velocity involving liquids.