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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	[-D debuglevel]	[-f filename] [-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 implment the required
       UBX-RXM-RAWX message. The NEO-M8T is known to work, but requires
       configuration with ubxtool.

       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
       -D [debuglevel] set debug level to [debuglevel].

       -f [filename] save RINEX	into [filename].

       -h makes	gpsrinex print a usage message and exit.

       -i [interval] wait [interval] seconds between epochs. OPUS accepts
       intervals of 1, 2, 3, 5,	10, 15 or,30 seconds. OPUS then	reduces	the
       data to 30 second intervals. Defeault is	30.

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

       -V makes	gpsrinex print its version and exit.

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 masurement 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

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

SEE ALSO
       One service known to work with obsrinex 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 3.03 format described here:
       ftp://igs.org/pub/data/format/rinex303_update1.pdf

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

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

The GPSD Project		  09 Nov 2018			   GPSRINEX(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | AUTHOR

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