rtcmdecode 1 13 Jul 2005 rtcmdecode decode RTCM104 streams into a readable format rtcmdecode -v debuglevel This tool is a decoder for RTCM-104, an obscure and complicated serial protocol used for broadcasting pseudorange corrections from differential-GPS reference stations. RTCM-104 is expected on standard input; an equivalent, 100%-information-preserving text format is written to standard output. You can use this tool with nc1 to examine RTCM feeds from DGPSIP servers. The decoder dump format is described in rtcm5; these lines go to standard output. As well as data the decoder also prints decoder status messages to standard error, as necessary. The -v option sets a verbosity level. It is mainly of interest to developers. gpsd8, xgps1, libgps3, libgpsd3, gpsprof1, gnuplot1, gpsfake1, rtcm5. The applicable standard is RTCM Recommended Standards for Differential NAVSTAR GPS Service RTCM Paper 194-93/SC 104-STD. Ordering instructions are accessible from the website of the Radio Technical Commission for Maritime Services under "Publications". This program will fail quietly, never achieving sync lock with the RTCM stream, on a non-little-endian machine. The decoder logic is sufficiently convoluted to confuse some compiler optimizers, notably in GCC 3.x at -O2, into generating bad code. Eric S. Raymond esr@thyrsus.com. This is a somewhat hacked version of an RTCM decoder originally written by Wolfgang Rupprecht. There is a project page for gpsd here.