NAME

       gpssubframe - tool to dump subframe sentences from gpsd

SYNOPSIS

       gpssubframe [-?] [--count COUNT] [--debug LVL] [--desc] [--device DEVICE] [--file FILE] [--help]
                   [--host HOST] [--load FILE] [--port PORT] [--progress] [--satpos] [--save FILE]
                   [--seconds SECONDS] [--test] [--time SECONDS] [--version] [-D LVL] [-f FILE] [-h] [-n COUNT]
                   [-V] [-x SECONDS] [server [:port [:device]]]

DESCRIPTION

       gpssubframe is a tool to connect to gpsd and dump decoded subframe data to stdout. This is only useful if
       your GNSS receiver can output GPS subframe messages, and is configured to do so. A working knowledge of
       IS-GPS-200 is also required. Keep your copy close at hand.

       gpssubframe does not require root privileges, and can be run concurrently with other tools connecting to
       the local gpsd without causing problems.

       The program will accumulate subframe message and output them by GPS satellite number on exit. By default
       the program never exits unless the user selects the number of seconds to run or number of messages to
       capture.

       By default gpssubframe connects to a gpsd running on the local host. Optionally a host, TCP/IP port
       number and remote device can be given.

OPTIONS

       -?, -h, --help
           -Print a usage message and exit.

       -c COUNT, --count COUNT
           Exit after COUNT subframe messages.

       --device DEVICE
           Connect to device DEVICE on gpsd host.

       -D LVL, --debug LVL
           Set debug level to LVL.

       --file FILE
           Read JSON from FILE instead of from gpsd..

       --host HOST
           Connect to gpsd on host HOST.

       --port PORT
           Connect to gpsd on port PORT.

       --progress
           Print progress reports as messages are received.

       --satpos
           Compute GPS satellite positions before exit.

       --time SEC
           Compute satellite position at time SEC in POSIX seconds.

       --test
           Run --satpos selftest code.

       -V, --version
           Print the program version, then exit.

       -x SEC, --seconds SEC
           Seconds of messages to parse. 0 to disable.

EXAMPLES

       First connfigure a u-blox 9-series to output subframe messages. Then have gpssubframe gather one complete
       set of subframes, then print the data organized by GPS satellite number. Then calculate and print the
       known satellite positions as well as the azimuth, elevation, and range from the current position:

           ubxtool -P 22 -e SFRBX
           gpssubframe -x 750 --satpos

       If staring at a blank screen for 12.5 minutes is too stressful, then enable progress messages:

           gpssubframe -x 750 --satpos --progress

SEE ALSO

       gpsd(8), gps(1), gpsprof(1), gpsfake(1), gpsctl(1), gpscat(1).

       IS-GPS-200 "NAVSTAR GPS Space Segment/Navigation User Segment Interfaces"

AUTHOR

       Gary E. Miller <gem@rellim.com>.