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

Provided by: gpsd-clients_3.22-4ubuntu2_amd64

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.

AUTHOR

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