Provided by: gpsd-clients_2.37-4_i386
rtcmdecode - decode RTCM104 streams into a readable format
rtcmdecode [-d] [-e] [-v debuglevel] [-V]
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 nc(1) to examine RTCM feeds from DGPSIP
servers or Ntrip broadcasters.
The decoder dump format is described in rtcm(5); these lines go to
standard output. As well as data the decoder also prints decoder status
messages to standard error, as necessary.
The -d option tells the program to decode RTCM-104 presented on
standard input to a text dump in the format of rtcm-104(5) on standard
output. This is the default behavior.
The -e option option tells the program to encode a text dump in the
format of rtcm-104(5) to standard output.
The -V option directs the program to emit its version number, then
The -v option sets a verbosity level. It is mainly of interest to
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".
BUGS AND LIMITATIONS
RTCM-104 represents floating-point quantities as an integer multiple of
a fixed scale factor. Editing an RTCM-104 dump can produce numbers that
are not an integer multiple of the scale factor for their field. If you
do this, the value actually packed into binary RTCM-104 will be rounded
down to the nearest scale unit, and dumping will show slightly
different numbers than those you entered.
The decoder logic is sufficiently convoluted to confuse some compiler
optimizers, notably in GCC 3.x at -O2, into generating bad code.
gpsd(8), cgps(1), libgps(3), libgpsd(3), gpsprof(1), gpsfake(1),
Eric S. Raymond <email@example.com>. This is a somewhat hacked version of
an RTCM decoder originally written by Wolfgang Rupprecht. There is a
project page for gpsd here.
1. Radio Technical Commission for Maritime Services