NMEAlike

NMEAlike is a family of text-based data sentence formats designed for exchanging navigational and environmental data between marine devices. It is inspired by the NMEA 0183 standard and is used in some open-source projects and vendor equipment. NMEAlike is not an official standard; rather, it is a descriptive label for similar sentence-based protocols that aim to trade data across GPS, AIS, sonar, weather sensors, and autopilots.

Sentences in NMEAlike begin with a dollar sign, followed by a talker identifier, a sentence type, and a comma-separated payload. The payload ends with a star and a two-hex-digit checksum calculated from all characters between the $ and the . The format is human-readable and tolerant of sparse fields. Field values are typically plain text or numeric strings, and missing fields are represented by empty entries.

Common sentence types include POS for position, HDG for heading, VEL for velocity, SENS for sensor readings, and ENV for environmental data. Data fields may include latitude and longitude in degrees and minutes, speed in knots, course over ground, depth in meters, wind speed and direction, temperature, and other sensor readings. Time and quality indicators are often included as optional fields. Parsers generally support both fixed-field and delimited approaches, allowing partial data refreshes without full sentence updates.

Interoperability and adoption: NMEAlike aims for backward compatibility with NMEA 0183 through compatibility modes and translation layers, while also supporting modern transport channels such as USB, RS-485, and TCP/IP. This makes it suitable for integration across marine navigation systems, autopilots, and sensor networks. Example applications include vessel data dashboards, fleet monitoring, and autonomous marine platforms.

Example sentence: $NMEALK,POS,3723.2475,N,12158.3416,W,0.0,0.01C