Which radar relies on the reception of signals that bounce off targets?

Primary radar operates on the principle of transmitting radio waves that bounce off objects, such as aircraft, and then returning to the radar system. This type of radar relies solely on the reflection of these signals to detect and determine the range and bearing of targets in its vicinity. The ability to detect these reflected signals allows primary radar to monitor the position and movement of various objects, making it particularly useful in air traffic control and other applications that require tracking of moving targets.

In contrast, secondary radar systems, such as those utilizing transponders, rely on the interaction between a ground-based radar transmitter and an airborne transponder that sends back information. A-Priori and transponder radar are not standard classifications in radar technology, which further emphasizes that primary radar is the correct response for this question. The fundamental mechanism of signal reflection is what distinguishes primary radar and solely determines its functionality in target detection scenarios.