What type of sensor is associated with radar systems such as AN/APR?

The correct answer, omni directional sensors, is linked to radar systems such as the AN/APR because these sensors are designed to detect radar signals coming from any direction. Omni directional sensors can surveil a wide area, making them particularly useful for applications in air defense and surveillance where threats can approach from various angles. They are engineered to monitor a broad spectrum of frequencies and detect the presence and characteristics of radar emissions, allowing operators to gather important information about multiple targets simultaneously.

In contrast, thermal sensors specialize in detecting heat signatures, infrared sensors work with infrared light, and visual sensors rely on visible light to capture images. Each of these sensor types has distinct functionalities and limitations that do not align with the primary purposes of radar systems that focus on detecting and analyzing electromagnetic waves. Thus, the capability of omni directional sensors to capture data from various directions is what makes them particularly suited for radar applications like the AN/APR systems.