GPSLOGNTP(1)                  GPSD Documentation                  GPSLOGNTP(1)

NAME
       gpslogntp - log gpsd data for ntpviz

SYNOPSIS
       gpslogntp [-h] [-l LOGFILE] [-o] [-w WAIT] [-v] [-V]

           -h, --help            show this help message and exit
           -l LOGFILE, --logfile LOGFILE
                                 append log data to LOGFILE instead of stdout
           -o, --once            log one line, then exit
           -w WAIT, --wait WAIT  wait WAIT seconds between log lines, default 5
           -v, --verbose         be verbose
           -V, --version         show program's version number and exit

DESCRIPTION
       gpslogntp connects to a local gpsd daemon and logs the number of
       satellites in use and the Time Dilution of Precision (TDOP).  gpslogntp
       can run as any user, no special privileges are required.  This log is
       intended to be used by ntpviz.

       The default is to write the data to stdout about once every 5 seconds.
       The log file looks like:

           # Time       Device     TDOP     nSat
           1483668619.0 /dev/ttyS0 0.820000 7
           1483668624.0 /dev/ttyS0 0.820000 7
           1483668629.0 /dev/ttyS0 0.820000 7

       Time is the POSIX time of when the log line is written.

       Device is the GPS device the data came from.

       TDOP is the Time Dilution of Precision as reported by the GPS.  Some
       GPS always output a static TDOP.

       nSat is the number of satellites in use.

       Formerly known as ntploggps and formerly part of NTPsec.

       Note: Many GNSS receivers always report TDOP as "1.0".

OPTIONS
       -h, --help
           Displays usage information and exits.

       -l LOGFILE, --logfile LOGFILE
           Append log data to LOGFILE instead of stdout

       -o, --once
           Log one line, then exit.

       -v, --verbose
           Be verbose

       -w WAIT, --wait WAIT
           Wait WAIT seconds after each log line.  The default is 5 seconds.
           This is just the minimum wait time.  gpsd may be reporting data at
           a much slower interval.

       -V, --version
           show program's version number and exit

USAGE
       gpslogntp
           This the simplest use of this program. It can be used to check the
           status of the local gpsd daemon.

       gpslogntp -l /var/log/ntpstats/gpsd -w 60 &
           This will continuously log the gpsd data in the background to the
           file /var/log/ntpstats/gpsd.  Only log every 60 seconds.

AUTHORS
       Gary E. Miller

EXIT STATUS
       One of the following exit values will be returned:

       0 (EXIT_SUCCESS)
           Successful program execution.

       1 (EXIT_FAILURE)
           The operation failed or the command syntax was not valid.

SEE ALSO
       gpsd(8), gps(1), ntpviz(1), ntpd(8).

RESOURCES
       Project web site:  <https://gpsd.io/>

COPYING
       This file is Copyright by the GPSD project
       This file is Copyright by the NTPSec project
       SPDX-License-Identifier: BSD-2-clause

AUTHOR
       Gary E. Miller

GPSD, Version 3.26                2025-05-06                      GPSLOGNTP(1)