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gpsrinex(1)                   GPSD Documentation                   gpsrinex(1)




NAME

       gpsrinex - Read data from gpsd convert to RINEX3 and save to a file.


SYNOPSIS

       gpsrinex [--agency AGENCY] [--ant_e EASTING] [--ant_h HEIGHT]
                [--ant_n NORTHING] [--ant_num NUM] [--ant_type TYPE]
                [--count COUNT] [--debug LVL] [--fileout FILE] [--help]
                [--interval INTERVAL] [--marker_name NAME]
                [--marker_type TYPE] [--observer OBSERVER] [--rec_num NUM]
                [--rec_type TYPE] [--rec_vers VERS] [--version] [-D LVL]
                [-f FILE] [-h] [-i INTERVAL] [-n COUNT] [-V] [server [:port
                [:device]]]


DESCRIPTION

       gpsrinex is a tool to connect to gpsd and output the received raw
       measurements as a RINEX 3 observation file. This is useful for sending
       raw measurements (pseudorange and carrierphase) from gpsd to a Precise
       Point Positioning (PPP) program or service.

       gpsrinex does not require root privileges, and can be run concurrently
       with other tools connecting to a local or remote gpsd without causing
       problems.

       gpsrinex needs the GPS receiver to be sending raw measurements to gpsd.
       Only a few GPS have this capability. In addition, the gpsd driver for
       that GPS must support raw mode. Currently only the u-blox driver has
       this support. Only a few u-blox 8 GPS implement the required
       UBX-RXM-RAWX message. The NEO-M8T is known to work, but requires
       configuration with ubxtool.

       Before using ubxtool be sure to set the UBXOPTS environment variable
       with the correct protocol version for your u-blox receiver. If your
       protocol version is 32.00, you would do this:

           export UBXOPTS="-P 32.00"

       RINEX has its own definitions and abbreviations. Be sure to consult
       their documentation. An observation file (.obs) contains data sets,
       called epochs, that contain the pseudorange and carrierphase for each
       satellite seen.

       gpsrinex by default will acquire 20 epochs spaced apart by 30 seconds.
       That will take 10 minutes to complete. Most users consider the 30
       second interval to be optimal. Many PPP programs require at least 1 or
       2 hours data, but no more than 24 or 48 hours of data. Most users
       consider 4 to 6 hours of data as a minimum for good accuracy.
       Additional hours will not yield much improvement.

       The output will consist of one RINEX 3 observation file that is ready
       to be read by your PPP program. The default filename will be in the
       form: gpsrinexYYYYJJJHHMMSS.obs. You can override this filename with
       the -f option.

       Optionally a server, TCP/IP port number and remote device can be given.
       If omitted, gpsrinex connects to localhost on the default port (2947)
       and watches all devices opened by gpsd.


OPTIONS

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

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

       -f FILE, --fileout FILE
           save RINEX into FILE.

       -i SECS, --interval SECS
           wait [interval] seconds between epochs. The interval can be
           specified to the millisecond. OPUS accepts intervals of 1, 2, 3, 5,
           10, 15 or,30 seconds. OPUS then reduces the data to 30 second
           intervals. Default is 30.000.

       -n COUNT, --count COUNT
           Causes COUNT epochs to be output. OPUS requires a minimum af 15
           minutes, and a maximum of 48 hours, of data.

       -V, --version
           makes gpsrinex print its version and exit.

       The following options set strings that are placed in the generated
       RINEX 3 obs file. They do not change how gpsrinex computes anything.

       --agency AGENCY
           The name of the agency creating the current file.

       --ant_num NUMBER
           The antenna serial number.

       --ant_type TYPE
           The antenna type.

       --marker_name NAME
           The marker name.

       --marker_type TYPE
           The marker type

       --observer OBSERVER
           The name of the observer (you).

       --rec_num NUM
           The receiver serial number.

       --rec_type TYPE
           The receiver type.

       --rec_vers VERS
           The receiver version.

       The following options set floating point numbers that are placed in the
       generated RINEX 3 obs file. They do not change how gpsrinex computes
       anything.

       --ant_e EASTING
           The antenna easting from marker in meters.

       --ant_h HEIGHT
           The antenna height from marker in meters.

       --ant_n NORTHING
           The antenna northing from marker in meters.


EXAMPLES

       Example 1:

       Create a 4 hour .obs file. With a running gpsd accessible on the
       localhost do all of the following, in order. Order matters.

       The raw measurement messages are long. Be sure your serial port speed
       is high enough:

           gpsctl -s 115200

       Disable all NMEA messages, and enable binary messages:

           ubxtool -d NMEA
           ubxtool -e BINARY

       The NEO-M8N will only reliably output raw measurements when only the
       GPS and QZSS constellations are enabled. If your PPP service can use
       GLONASS, then enable that as well. Be sure to disable, before enable,
       so as not to momentarily have too many constellations selected.
       ubxtool, as recommended by u-blox, enables the QZSS constellation in
       tandem with GPS. Disable all constellations, except GPS (and QZSS):

           ubxtool -d BEIDOU
           ubxtool -d GALILEO
           ubxtool -d GLONASS
           ubxtool -d SBAS
           ubxtool -e GPS

       Verify the constellations enabled:

           ubxtool -p CFG-GNSS

       Enable the good stuff, the raw measurement messages:

           ubxtool -e RAWX

       Verify raw data messages are being sent:

           ubxtool | fgrep RAWX

       You should see this output:

           UBX-RXM-RAWX:
           UBX-RXM-RAWX:

       Collect 4 hours of samples at 30 second intervals, save the RINEX 3
       observations in the file today.obs:

           gpsrinex -i 30 -n 480 -f today.obs

       Wait 4 hours. Enjoy a meal, or do some exercise. When gpsrinex
       finishes, upload the file today.obs to your favorite PPP service.

       Example 2:

       Collect raw measurement data from a remote gpsd. The process it later
       with gpsrinex and gpsprof.

       Ensure the GPS is configured properly, as shown in Example 1.

       Grab 4 hours of raw live data from remote gpsd at 10.168.1.2:

           gpspipe -x 14400 -R 10.168.1.2 > 4h-raw.ubx

       When gpspipe is complete, feed the data to gpsfake:

           gpsfake -1 -P 3000 4h-raw.ubx

       In another window, feed the data to gpsrinex. Use -n 10000000 so that
       all the data from the raw file is used::

           gpsrinex -i 30 -n 1000000 :3000

       Repeat the process with gpsfake to send the data to gpsprof.


SEE ALSO

       One service known to work with gbsrinex output is at:
       https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php

       OPUS requires 2 frequency observation files.
       https://www.ngs.noaa.gov/OPUS/

       The curious can find the RINEX 3.04 format described here:
       ftp://igs.org/pub/data/format/rinex304.pdf

       gpsd(8), gpsfake(1), ubxtool(1).


AUTHOR

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



The GPSD Project                6 December 2020                    gpsrinex(1)

gpsd 3.22 - Generated Sat Jan 16 09:34:03 CST 2021
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