In maritime applications, NMEA (National Marine Electronics Association) format is widely used for data exchange between various navigation and communication equipment onboard vessels. NMEA messages are ASCII-based and are typically transmitted over serial connections (RS-232 or NMEA 0183) between devices like GPS receivers, autopilots, radars, and chart plotters.

The data distribution unit in maritime using NMEA format typically involves the transmission and reception of NMEA messages. These messages contain information such as GPS position, speed over ground, heading, depth, wind speed, and other relevant navigational data. The data distribution unit acts as a hub, receiving NMEA messages from various sensors and devices on the vessel and distributing them to other systems or equipment that require the information.

Some common NMEA sentences used for data distribution in maritime applications include:

• GGA (Global Positioning System Fix Data): Provides essential fix data such as latitude, longitude, altitude, and time.
• RMC (Recommended Minimum Navigation Information): Provides essential GPS data including latitude, longitude, speed over ground, course over ground, and time.
• GLL (Geographic Position - Latitude/Longitude): Provides latitude and longitude data.
• VTG (Track Made Good and Ground Speed): Provides information about the speed over ground and course over ground.
• HDG (Heading, Deviation, Variation): Provides information about the vessel's heading.
• DBT (Depth Below Transducer): Provides depth information.
• MWV (Wind Speed and Angle): Provides information about wind speed and angle.

The data distribution unit in maritime applications typically collects these NMEA messages from various sensors and systems, processes them as needed, and then distributes them to navigation displays, chart plotters, radar systems, and other equipment where the data is required for navigation, situational awareness, and decision-making.