Hawkynt

NMEA-0183

NMEA 0183 sentence checksum for GPS and marine navigation systems. XOR of all characters between ‘$’ and ‘’ delimiters. Standard protocol format: $…data…CC where CC is 2-digit hex checksum. Used in marine electronics worldwide.

Properties

Property	Value
Category	Checksums
Sub-category	Navigation Protocol
Security status	🎓 Educational Only
Complexity	Beginner
Inventor	National Marine Electronics Association
Year	1983
Origin	🇺🇸 United States
Source	algorithms/checksum/nmea-0183.js

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Notes

• Sentence format: $<data>*<checksum>
• Checksum: XOR of all bytes between $ and *
• Output: 2-digit hexadecimal (00-FF)
• Common sentences: GPGGA, GPGLL, GPGSA, GPGSV, GPRMC
• Used in: GPS receivers, marine navigation, AIS
• Simple but effective for detecting transmission errors
• Not designed for security, only error detection

Documentation

• NMEA 0183 on Wikipedia
• NMEA Sentence Structure
• GPS Sentence Parsing

References

• pynmea2 NMEA checksum implementation

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — GPRMC sentence

Field	Value
input	4750524d432c3132333531392c412c34 3830372e3033382c4e2c30313133312e 3030302c452c3032322e342c3038342e 342c3233303339342c3030332e312c57
expected	6a

Vector 2 — GPGGA sentence

Source: NMEA sentence checksum

Field	Value
input	47504747412c3132333531392c343830 372e3033382c4e2c30313133312e3030 302c452c312c30382c302e392c353435 2e342c4d2c34362e392c4d2c2c
expected	47

Vector 3 — Simple test

Source: XOR checksum

Field	Value
input	54455354
expected	16

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