What is an example of an active sensor in radar systems?

An active sensor in radar systems is defined by its capability to both emit its own energy and detect the reflection of that energy from objects in its environment. This allows the sensor to determine the range, speed, and characteristics of various objects by analyzing the reflected signals.

In the context of radar systems, an example of an active sensor would indeed be a radar system that emits its own energy to detect objects. This distinguishing feature of active sensors is critical because it enables proactive data collection about the surroundings, leading to improved situational awareness and object detection capabilities.

Other options, while related to sensing technologies, do not qualify as active sensors. For instance, a sensor that only receives reflected signals would be passive, as it relies on external energy sources rather than generating its own. A system using ambient light for detection also falls into the passive category, as it does not emit its own signals. Similarly, a device that monitors electronic signals without transmission is passive and does not engage in active emission of energy, thus making it incapable of active sensing capabilities.