A new variant of a Navy-developed navigation-and-combat systems interface was set to go through shipboard testing on board the Oscar Austin (DDG-79) in late September 2000 to evaluate incremental upgrades for the system that will provide new electronic charting capabilities and linkage to shipboard gun systems. Earlier versions of the system, which is called the navigation sensor system interface (NavSSI), presently is installed on about 70 ships—including surface combatants, amphibious ships, and aircraft carriers. The NavSSI program is managed by the navigation systems program office of the Space and Naval Warfare Systems Command (SpaWar).
Ship program managers of the Naval Sea Systems Command (NavSea) meanwhile are looking more closely at expanding the use of commercially built integrated bridge systems to provide precise navigation and ship-steering control functions. Integrated bridge systems, which automate many bridge functions and thereby reduce manpower needs, are employed widely in commercial shipping.
The Sea Systems Command's interest in commercial navigation systems supports the thinking of the top-level smart-ship executive steering committee that, in accordance with the Navy's "smart-fleet" charter, has endorsed a shift to the use of common software, logistics support, training, and technical refresh procedures throughout the surface fleet. The smart-fleet initiative has directed the Navy's smartship, smart-gator, and smart-- carrier efforts to incorporate commercial systems and technology to cut shipboard workload and reduce manning and life-cycle support costs.
SpaWar's navigation sensor system interface provides realtime transmission of navigation data from the ship's navigation systems to sensor and missile and gunfire control systems to support weapons engagement. The system also provides electronic-chart data to a pair of workstations on the bridge for use in ship navigation.
Managers in the SpaWar navigation office say, however, that the system is intended primarily to provide real-time connectivity between navigation and combat systems. They add that a commercial integrated bridge system, designed for voyage management for large commercial vessels, is better suited for providing non-real-time ship control functions, including integrated track and speed piloting, voyage planning, collision avoidance, selected surface-search radar control, alarm monitoring, and optimized route planning to minimize fuel consumption.
Commercial bridge systems built by Litton Marine Systems, Raytheon Marine, and Kelvin-Hughes (a U.K.-based company) also provide radar overlay, universal chart-reader capability, and interfaces to an automatic radar plotting aid. They also are integrated with ship machinery control and integrated condition-assessment systems. Both the Litton and Raytheon systems now in service on Navy ships also provide workstations in the combat information center for display of navigation data.
The Aegis program office is installing, through its smart-ship engineering control systems equipment upgrade for Ticonderoga (CG-47)-class cruisers, an integrated bridge system built by Litton Marine. The system runs the company's voyage management system software. The smart-ship upgrade will go on board all 27 cruisers, which already are fitted with the NavSSI for the combat system/navigation interface. The Litton integrated bridge also is on board the Cyclone (PC-1)-class patrol ships, the Iwo Jima (LHD-7), and the command ship La Salle (AGF-3). Litton also will install its system on board new San Antonio (LPD-17)-class amphibs and air-cushion landing craft through a service-life extension program now getting started.
Raytheon Marine provided an integrated bridge systems for the Whidbey Island (LSD-41)-class amphib Rushmore (LSD-47), which was intended as a first ship of a smart-gator upgrade for the class. The Navy canceled a planned release for proposals for smart-gator systems last spring, but still hopes to pursue it when funding becomes available. Raytheon also has delivered its Pathfinder navigation radars to six aircraft carriers as well as several amphibs and Avenger (MCM-1)-class mine countermeasures ships.
The Litton Marine and Raytheon integrated bridge software systems comply with the commercial electronic charting standard, electronic chart display and information system (ECDIS). Litton has invested corporate funds to achieve compliance with the Navy's more stringent version that demands more precise standards for tactical navigation, such as minefield avoidance. The Chief of Naval Operations has directed NavSea to achieve full electronic charting and ECDIS compliance by 2007.
The NavSSI consists of a real-time subsystem that accepts data from navigation systems, including radars, global positioning system receivers, speed logs, and inertial navigation systems, and processes it for transfer, through either point-to-point interfaces or ship networks to the systems that require the data.