Background: Tags and transponders are commonly used for underwater applications such as tracking and navigation. However, most underwater tag identification systems rely on an active source system and electronic hardware to broadcast a beacon acoustic signal, resulting in higher production and operating costs, thus limiting their practical applications and widespread use.
Technology:Karim Sabra and Brendan Nichols from the School of Mechanical Engineering at Georgia Tech have developed an entirely passive acoustic tag (referred to as an "AcoustiCode") to mark underwater targets. The lack of powered electronics makes it very low cost and simple to manufacture and allows it to be deployed long term without maintenance. AcoustiCodes can encode information since they have unique acoustic signatures that can be detected and read underwater by acoustic SONAR, akin to conventional optical barcodes read by laser scanners. However, contrary to conventional optical barcodes, AcoustiCode tags can be utilized underwater, even in poor or zero visibility (such as in turbid and murky waters), which does not affect the propagation of acoustic waves. The information is encoded in a unique machined 3D pattern on the surface of the AcoustiCode tags, which are easily deployed and recovered and can be individually calibrated. Once detected and read by the SONAR system, the range and bearing information can be used to accurately determine the AcoustiCode positioning with respect to the SONAR platform orientation. Furthermore, a unique binary code can be identified for each AcoustiCode to convey information regarding the nature and type of target on which the AcoustiCode is mounted.
Potential Commercial Applications: This invention is ideal for use in both underwater navigation and underwater target identification purposes. Applications may include mine and safe passage marking, ROV/AUV operations, hydrographic and oceanographic surveying, as well as telecom/power/oil/gas/seismic/fishing asset and equipment marking and monitoring.
Benefits / Advantages:
- Can encode information in its unique acoustic signature that can be read underwater by acoustic SONAR
- Compatible with all types of sonar, from hull-mounted mine-hunting and sidescan devices to fish-finders and echo-sounders
- Requires no power and has no active or electronic elements, making it very low cost and simple to manufacture and allowing it to be deployed long term without maintenance
- Ideal for use in both underwater navigation and underwater target identification purposes