What are the two primary modes of operation for SONAR systems?

The two primary modes of operation for SONAR (Sound Navigation and Ranging) systems are active and passive.

In the active mode, SONAR systems emit sound waves into the water, which then bounce off objects, such as submarines or the seafloor, and return to the sensor. This allows for distance measuring and object detection. Active SONAR is beneficial for locating and identifying objects but can potentially give away the position of the vessel using it due to the sound waves it generates.

On the other hand, passive SONAR systems do not emit any sound waves. Instead, they listen for sounds made by other objects, such as vessels, marine life, or underwater machinery. By analyzing these sounds, passive SONAR can detect, track, and classify objects in the water without revealing the sensor's location. This mode is crucial for stealth operations, as it allows a vessel to gather information without actively broadcasting its presence.

The other choices—manual and automated, dynamic and static, and continuous and intermittent—do not accurately capture the fundamental operations of SONAR systems. Manual and automated refer more to control methods rather than operational modes, while dynamic and static, and continuous and intermittent do not apply specifically to how SONAR systems function in terms of detection