What does an aircraft's speed and angle in reference to a radar site determine?

The aircraft's speed and its angle in reference to a radar site are critical in determining the radial velocity. Radial velocity is a measure of how quickly an object is moving toward or away from the radar site, which is influenced by both the speed of the aircraft and its direction relative to the radar. This concept is fundamental in radar technology and is used for tracking the movement of aircraft. By analyzing the frequency shift in the radar waves reflected off the aircraft (known as the Doppler effect), the radar system can calculate the radial velocity, which indicates whether the aircraft is approaching or retreating from the radar source.

The other concepts mentioned, such as tangential phase, tangential pattern, and blind pattern and phase, do not directly relate to the calculation of speed and angle with respect to a radar site. Instead, they refer to different aspects of wave behavior or radar signal characteristics that are not concerned with the straightforward determination of velocity in a radar context. Thus, the focus on radial velocity as a direct outcome of speed and angle relative to radar is what makes it the appropriate choice in this scenario.