gpsdecode - decode GPS, RTCM or AIS streams into a readable format
gpsdecode [-?] [--ais] [--decode] [--debug LVL] [--encode] [--help] [--json] [--minlength] [--nmea] [--split24] [--types typelist] [--unscaled] [--verbose] [--version] [-c] [-d] [-D LVL] [-e] [-h] [-j] [-m] [-n] [-s] [-t typelist] [-u] [-v] [-V]
This tool is a batch-mode decoder for NMEA and various binary packet formats associated with GPS, AIS, and differential-correction services. It produces a JSON dump on standard output from binary on standard input. The JSON is the same format documented in gpsd(8); this tool uses the same decoding logic as gpsd, but with a simpler interface intended for batch processing of data files.
All sensor-input formats known to the GPSD project can be decoded by this tool. These include: NMEA, AIVDM (the NMEA-derived sentence format used by AIS, the marine Automatic Identification System), RTCM2, and all supported GPS binary formats (notably including SiRF). See gpsd(8) for applicable standards and known limitations of the decoding logic.
You can use this tool with nc(1) to examine AIS feeds from AIS pooling services, RTCM feeds from RTCM receivers or NTRIP broadcasters.
-?, -h, --help
-D LVL, --debug LVL
-t TYPES, --types TYPES
AIS DSV FORMAT¶
With the -c, --ais option, dump lines are values of AIS payload fields, pipe-separated, in the order that they occur in the payload. Spans of fields expressing a date are emitted as an ISO8601 timestamp (look for colons and the trailing Z indicating Zulu/UTC time), and the 19-bit group of TDMA status fields found at the end of message types 1-4 are are dumped as a single unsigned integer (in hex preceded by "0x"). Unused regional-authority fields are also dumped (in hex preceded by "0x"). Variable-length binary fields are dumped as an integer bit length, followed by a colon, followed by a hex dump.
Eric S. Raymond <firstname.lastname@example.org>.
|6 December 2020||The GPSD Project|