Photo: Northrop Grumman
The SeaFIND inertial navigation system (INS) on April 1 received Type Approval from the U.S. Coast Guard, confirming that it meets an important international performance benchmark.
SeaFIND — Sea Fiber Optic Inertial Navigation with Data Distribution — was developed by Northrop Grumman for small- to medium-size combatant and auxiliary ships. With its small footprint, it can also be used on unmanned underwater and surface vehicles, or coastal and offshore patrol vessels.
SeaFIND builds from the software, algorithms and digital messages used on the MK39, a ring-laser INS installed around the world with the U.S. Navy and partner fleets. Instead of a ring-laser gyro, SeaFIND uses Northrop Grumman’s enhanced fiber-optic gyro technology (eFOG). eFOG maintains equivalent performance in a much smaller footprint — yet is more reliable.
“Fiber-optic technology is inherently more reliable with a higher mean time between failure rate than ring-laser gyro technology, which requires a high-voltage laser to operate and degrades over time,” explained Tom Disy, manager of Strategic Planning for Maritime/Land Systems & Sensors. An improved version of FOG, eFOG allows for the inertial measurement unit (IMU) within SeaFIND to achieve dependable navigation-grade performance, Disy explained.
SeaFIND’s embedded Navigation Data Distribution System (NAVDDS) software collects all the navigation data the ship receives, including SeaFIND and GPS data. NAVDSS then provides this data to other ship systems in a time-corrected, system-specific format. Time correction is necessary to maintain accuracy requirements, especially for applications requiring highly accurate dynamic attitude. NAVDDS’ low data latency allows the system to interface with any users that require accurate position and timing, such as combat systems or TACAN (tactical air navigation systems).
The SeaFIND INS complements the data received from GNSS. “Our inertial systems utilize GPS data when available; however, the SeaFIND INS also provides other key navigation data, including heading, roll and pitch,” Disy said. “The SeaFIND INS provides reliable position data for a significant period of time if the GNSS system data becomes unreliable or unavailable for any reason.”
SeaFIND is not subject to ITAR (International Traffic in Arms Regulations) and available for use by domestic and international navies.