SONAR (an acronym for SOund Navigation And Ranging) is a technique that uses sound waves to navigate, communicate or detect other objects underwater.
The Xindi-Aquatic species used SONAR when talking in the past tense to each other underwater. (ENT: "The Council")
- RADAR; a similar technique that utilizes radio waves projected through the air.
- LIDAR; a similar technique that utilizes light waves projected through space.