1RTCMDECODE(1)                                                    RTCMDECODE(1)
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NAME

6       rtcmdecode - decode RTCM104 streams into a readable format
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SYNOPSIS

9       rtcmdecode [-d] [-e] [-v debuglevel] [-V]
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DESCRIPTION

13       This  tool is a decoder for RTCM-104, an obscure and complicated serial
14       protocol used for broadcasting pseudorange corrections  from  differen‐
15       tial-GPS reference stations. RTCM-104 is expected on standard input; an
16       equivalent, 100%-information-preserving text format is written to stan‐
17       dard output.
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20       You  can  use  this  tool  with nc(1) to examine RTCM feeds from DGPSIP
21       servers or Ntrip broadcasters.
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24       The decoder dump format is described in  rtcm(5);  these  lines  go  to
25       standard output. As well as data the decoder also prints decoder status
26       messages to standard error, as necessary.
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OPTIONS

30       The -d option tells the program to decode RTCM-104 presented  on  stan‐
31       dard input to a text dump in the format of rtcm-104(5) on standard out‐
32       put. This is the default behavior.
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35       The -e option option tells the program to encode a  text  dump  in  the
36       format of rtcm-104(5) to standard output.
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39       The  -V option directs the program to emit its version number, then ex‐
40       it.
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43       The -v option sets a verbosity level. It is mainly of interest  to  de‐
44       velopers.
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APPLICABLE STANDARDS

48       The  applicable standard is RTCM Recommended Standards for Differential
49       NAVSTAR GPS Service RTCM Paper 194-93/SC 104-STD.
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52       Ordering instructions are accessible from  the  website  of  the  Radio
53       Technical  Commission for Maritime Services: http://www.rtcm.org/ under
54       "Publications".
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BUGS AND LIMITATIONS

58       RTCM-104 represents floating-point quantities as an integer multiple of
59       a fixed scale factor. Editing an RTCM-104 dump can produce numbers that
60       are not an integer multiple of the scale factor for their field. If you
61       do this, the value actually packed into binary RTCM-104 will be rounded
62       down to the nearest scale unit, and dumping will show slightly  differ‐
63       ent numbers than those you entered.
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66       The  decoder  logic is sufficiently convoluted to confuse some compiler
67       optimizers, notably in GCC 3.x at -O2, into generating bad code.
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SEE ALSO

71        gpsd(8),  gps(1),  libgps(3),  libgpsd(3),   gpsprof(1),   gpsfake(1),
72       rtcm-104(5).
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AUTHOR

76       Eric S. Raymond <esr@thyrsus.com>. This is a somewhat hacked version of
77       an RTCM decoder originally written by Wolfgang Rupprecht.  There  is  a
78       project page for gpsd  here: http://gpsd.berlios.de/.
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83                                                                 RTCMDECODE(1)
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