What does a DIFAR system utilize to provide bearing data?

A DIFAR (Directional Frequency and Range Acoustic Monitoring) system utilizes hydrophone arrays to provide bearing data. Hydrophones are underwater microphones designed to detect and measure sound waves in the ocean, which is crucial for submarine and anti-submarine operations. The hydrophone arrays can determine the direction of incoming sounds, such as those produced by submarines or marine life, enabling the system to accurately calculate the bearing of these sounds based on their time of arrival at different points in the array.

This capability is essential for situational awareness and tactical decision-making in naval operations, allowing for effective sonar tracking and engagement. The other options, such as thermal sensors, pressure gauges, and transistors, do not possess the ability to detect sound underwater or provide directional data, which is why they are not relevant in the context of the DIFAR system.