What phenomenon does the pulse doppler method utilize to detect moving targets?

The pulse Doppler method relies on the Doppler effect to detect moving targets. This phenomenon occurs when there is a change in the frequency or wavelength of waves in relation to an observer moving relative to the wave source. In radar systems, when a radar signal is transmitted and hits a moving target, the frequency of the returned signal will differ from the transmitted signal due to the relative motion between the radar system and the target.

If the target is moving toward the radar, the frequency of the reflected signal increases (a blue shift), while if it is moving away, the frequency decreases (a red shift). By analyzing these frequency shifts, the radar system can determine both the speed and direction of the moving target. This capability is crucial for various applications in defense, aviation, and surveillance systems, providing accurate information about target dynamics.

The other options presented do not apply to the pulse Doppler method. Acoustic waves pertain to sound, while electromagnetic interference deals with disruptions in electronic signals, and thermal imaging focuses on detecting infrared radiation rather than utilizing frequency changes due to motion.