Distributed Acoustic Sensing (DAS) is a type of technology that can detect acoustic signals. Sound waves are the most common example of acoustic waves. These waves occur due to the force fields. Acoustic waves are pressure waves after all. The force going through the materials causes pressure replacements. We call these replacement phenomena acoustic waves.
Single point sensors are detecting device that gets signals at only one place. There is only one detection point such as the tip of the needle. On the contrary, in distributed sensors, these sensors or sensor-like structures are continuous. Not like many single sensors but a continuous one. FOTAS uses fiber optic cables for Distributed Acoustic Sensing. Most of the time, DAS systems use fiber optic cables. Light waves propagate into the fiber optic cable affected by acoustic waves. These affected lights can be detected by devices for instance Optical Time Domain Reflectometry (OTDR).
Distributed Acoustic Sensing technology refers to a system that includes optoelectronic products which can perform real-time control and measurement through fiber optic cables extending across the targeted borders. The most basic way to comprehend FOTAS technology is to imagine yourself on a treadmill. It is assumed that as you move against the direction of a treadmill, the sound waves will spread around. Those who are at a certain distance from there can understand that there is someone on the treadmill through real-time monitoring even they aren’t in the same room.
Throughout the aforementioned process, acoustic signals are measured by Distributed Acoustic Sensors at each point of the fiber cable. Unlike sensors that measure at determining fixed points, fiber cable is used as a sensor in the DAS system. In other words, distributed acoustic sensor system turns fiber cable into microphones.