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UBXTOOL(1) GPSD Documentation UBXTOOL(1)


ubxtool - u-blox tool


ubxtool [-?] [--command command] [--delitem item,layers] [--device device] [--disable disable] [--enable enable] [--file file/device] [--getitem item,layer,position,end] [--help] [--host host] [--inspeed speed] [--port port] [--portid port] [--preset preset] [--protver protver] [--rawfile rawfile] [--readonly] [--setitem item,val,layers] [--setspeed setspeed] [--timestamp] [--verbosity verbosity] [--version] [--wait wait] [-c command] [-d disable] [-e enable] [-f file/device] [-g item,layer,position,end] [-h] [-i port] [-p preset] [-P protver] [-r] [-R rawfile] [-S setspeed] [-s speed] [-t] [-V] [-v verbosity] [-w wait] [-x item,layers] [-z item,val,layers] [[server[:port[:device]]]]


ubxtool is a tool for u-blox GPS. If you do not have a u-blox GPS then can stop reading now.

This tool operates with your u-blox GPS at a very low level. To understand ubxtool you must first be familiar with your u-blox GPS and the documentation for the u-blox binary protocol. The u-blox protocol varies greatly depending on GPS model and firmware revision. Use the u-blox documentation for your model and firmware.

ubxtool can decode common u-blox binary messages, poll the GPS status, enable and disable GPS features, and send user generated commands to the GPS. It can read binary messages from a file. It can read and write directly through a serial device, or through a running gpsd instance.


The program accepts the following options:

-?, -h, --help

Makes ubxtool print a usage message and exit. Use with -v 2 to see all enable/disable and preset values. Use with -v 3 to additionally see all configuration items (long).

-c COMMAND, --command COMMAND

Send a command to the GPS. Accepts one parameter, COMMAND, a comma-separated list of hexadecimal bytes specifying the class, the ID, and any needed payload. The header, length, and checksum are added automatically.

--device DEVICE

The DEVICE on the gpsd to connect to. Defaults to all.

-d OPTION, --disable OPTION

Disable an option in the GPS. Accepts one parameter, OPTION, the option to disable. Use -h -v 2 to see all possible OPTIONs. A few possible OPTIONs are:


Disable use of the BeiDou (COMPASS) constellation.


Disable sending of the basic binary messages.


Disable sending of ECEF binary messages.


Disable use of the GALILEO constellation.


Disable use of the GLONASS constellation.


Disable use of the GPS and QZSS constellations.


Disable sending of NED binary messages. UBX-NAV-VELNED and UBX-NAV-RELPOSNED.


Disable sending basic NMEA messages. The messages are GBS, GGA, GSA, GGL, GST, GSV, RMC, VTG, and ZDA.


Disable TIMEPULSE 0.


Disable sending of the UBX-RXM-RAWX messages.


Disable use of the SBAS constellation.


Disable use of the SFRBX messages.


Disable survey-in mode with TMODE2.


Disable sending UBX-TIM-TP.

-e OPTION, --enable OPTION

Enable an option in the GPS. Accepts one parameter, OPTION, the option to enable. -e accepts the same OPTIONs as -d, except the action is to enable the option.

-f FILE, --file FILE

Connect to a file or device. Accepts one parameter, FILE, the file or device to open. Files are opened read-only. Character devices are opened read/write, unless the -r parameter is given. Requires the pyserial module.


Get the value of ITEM from LAYER, starting at POSITION, up to END key/value pairs (UBX-CFG-VALGET). All parameters past ITEM are optional and decimal. If LAYER is absent, then layers 0, 1, 2 and 7 are all requested. See the section on CONFIGURATION ITEMS

--host HOST

Connect to the gpsd on HOST (server). Defaults to localhost.

-i port, --portid port

Specifies port ID # (interface) for port-related commands such as UBX_CFG-PRT.

-p PRESET, --preset PRESET

Send a preset command the GPS. Usually accepts one parameter, PRESET, the name of the command to send. A few PRESETS, like LOG-FINDTIME, accept additional comma separated parameters. More than one -p may be used.

Only the common PRESETS are shown here. To see the full list, including optional parameters, run "ubxtool -h -v 2".


Coldboot the GPS (UBX-CFG-RST).


Hotboot the GPS (UBX-CFG-RST).


Configure the Dynamic Platform Model to model. (UBX-CFG-NAV5). Model is the decimal number of the desired mode.


Set power management settings (UBX-CFG-PMS). "PMS,pow" where pow is powerSetupValue.


Set measurement and nav rate (UBX-CFG-RATE). "RATE,meas,nav" meas is the measRate in milli seconds. The nav argument is the navRate in cycles and defaults to 1


Reset configuration to defaults (UBX-CFG-CFG).


Save current configuration (UBX-CFG-CFG).


Reset the odometer (UBX-MON-RESETODO).


Poll GPS version (UBX-MON-VER).


Warmboot the GPS (UBX-CFG-RST).

Most PRESET parameters are simple poll commands. They merely poll the GPS to respond with the associated message. For example "ubxtool -p CFG-GNSS" asks the GPS to respond with a UBX-CFG-GNSS message describing the current GNSS configuration. Increase the verbosity of the output by adding the "-v 2" or "-v 3" options.

--port PORT

Use PORT to connect to gpsd. Defaults to 2947.

-P protver, --protver protver

Sets the protocol version to use for sending commands. Minimum 6 (Antaris 4). Use "ubxtool -p MON-VER" to see the version your receiver supports. Many newer u-blox receivers will fail silently or oddly if this is not set correctly. Default 10 (u-blox 5).

-r, -readonly

Read only. Do not send anything to the GPS.

-R RAW, --rawfile RAW

Save all raw serial data received from the GPS into the file RAW.

-s SPEED, --inspeed SPEED

Set local serial port speed to SPEED bps. Default 9,600 bps.

-S SPEED, --setspeed SPEED

Set the GPS serial port speed to SPEED bps.

-t, --timestamp

Timestamp decoded messages with seconds since the epoch. Use it twice and also get UTC time.


Set verbosity level to VERBOSITY. Verbosity can be from 0 (very quiet), 2 (decode messages), to 4 (very noisy). Default 1.

-V, --version

Print ubxtool version and exit.

-w WAIT, --wait WAIT

Wait for WAIT seconds before exiting. Default 2 seconds.


Delete the value of ITEM name from LAYERS. The bit map LAYERS is optional. By default, delete in both the BBR and FLASH layers in the receiver (UBX_CFG-VALDEL). Returning to the reciver default for that item. See the section on CONFIGURATION ITEMS


Set the value of ITEM name to VAL in LAYERS in the GPS (UBX-CFG-VALSET). VAL and the bit mask LAYERS are decimal. ",LAYERS" is optional. The default LAYERS are RAM and FLASH See the section on CONFIGURATION ITEMS


By default, ubxtool collects data from all compatible devices on localhost, using the default GPSD port 2947. An optional argument may specify a server to get data from. A colon-separated suffix is taken as a port number. If there is a second colon-separated suffix, that is taken as a specific device name to be watched. Further details on the gps(1) man page.


Configuring u-blox GPS with the traditional configuration messages is fraught with problems. Many configuration messages interact in odd ways. Something as simple as changing the serial port speed requires you to read the current configuration using UBX-CFG-PRT for the proper port, merging in the change, the writing back the changed UBX-CFG-PRT message. Or just guessing at the current configuration and overwriting it all.

The u-blox 9 series, protocol version 27+, tries, but does not completely succeed, to solve the problem with Configuration Items. If your GPS does not support protocol version 27+, then this section does not apply to you.

Most of the configuration variables in the GPS have been assigned a 32-bit Key ID. Each Key references one specific value. A typical receiver may have over 1,100 Key IDs. Each Key ID has been assigned a Key Name. Most of the Key Names are documented by u-blox and supported by ubxtool. To see all the Key Name understood by ubxtool do: "ubxtool -h -v 3".

To get the value related to an item, use "-g ITEM".

To reset the value related to an item to it default value, use "-x ITEM".

To set an ITEM name to a value, use "-z ITEM,VAL".

If you only want to set an ITEM in one layer, use "-z ITEM,VAL,LAYER".

See the EXAMPLES section for concrete examples.


All examples assume that UBXOPTS is set with the protocol version of your receiver. Be sure to replace the "-P 18" with your correct prototype version.

export UBXOPTS="-P 18"

Dump configuration and status of the GNSS recceiver. The "-w 4" is to provide extra time for the operations to complete.

ubxtool -p CONFIG -p STATUS -w 4 -v 2

Decode raw log file:

ubxtool -r -f ublox-neo-m8n.log

Change GPS port speed of device on /dev/ttyAMA0 to 230,400 bps:

ubxtool -S 230400 -f /dev/ttyAMA0

Watch entire GPS reset cycle, include $GPTXT messages:

ubxtool -p COLDBOOT -w 20 -v 2

Poll Enabled Constellations:

ubxtool -p CFG-GNSS

Dump gpsd data from a remote server named

ubxtool -w 5

Version 27+ examples

The following examples require a GPS supporting protocol 27 or greater. Be sure to set your protocol version first:

export UBXOPTS="-P 32"

To check the current dynamic model, change it to 6 (AIR1, Airborne with <1g acceleration), revert to the default setting, and verify the faults was restored.


version 1 layer 0 reserved 0,0
layers (ram)
item CFG-NAVSPG-DYNMODEL/0x20110021 val 2 [...] $ ubxtool -z CFG-NAVSPG-DYNMODEL,6 [...] UBX-ACK-ACK:
ACK to Class x6 (CFG) ID x8a (VALSET) [...] $ ubxtool -g CFG-NAVSPG-DYNMODEL [...] UBX-CFG-VALGET:
version 1 layer 0 reserved 0,0
layers (ram)
item CFG-NAVSPG-DYNMODEL/0x20110021 val 6 [...] $ ubxtool -x CFG-NAVSPG-DYNMODEL [...] UBX-ACK-ACK:
ACK to Class x6 (CFG) ID x8c (VALDEL) [...] $ ubxtool -g CFG-NAVSPG-DYNMODEL [...] UBX-CFG-VALGET:
version 1 layer 0 reserved 0,0
layers (ram)
item CFG-NAVSPG-DYNMODEL/0x20110021 val 6

Notice that the current DYNMODEL stayed at 6 (AIR1). The "-x" only affects the saved setting, not the current setting. To change the current setting you must set it with "-z".

Getting all the Configuration Items in a group one by one could be very tedious. VAL-GET allows you to wild card the item number and dump all the items in a group. To get all the CFG-TP items in ram, the currently active ones, you can do this:

$ ubxtool -g CFG-TP,0

version 1 layer 0 position 0
layers (ram)
item CFG-TP-TP1_ENA/0x10050007 val 1
item CFG-TP-SYNC_GNSS_TP1/0x10050008 val 1
item CFG-TP-USE_LOCKED_TP1/0x10050009 val 1 [...]

The truly masochistic can dump all the Configuration Items by wildcarding the group. Dumping all 1,000+ of them, 64 at a time, could still be tedious. The -g parameter optionally allows you to specify the starting position to get from, as well as the ending position. To get all the known, and unknown, items supported by the receiver that are currently in ram:

$ ubxtool -g CFG,0,0,1200 | fgrep "item CFG-"

item CFG-1-1/0x10010001 val 0
item CFG-1-1/0x10010101 val 0
item CFG-4-1/0x10040001 val 1
item CFG-4-2/0x10040002 val 0
item CFG-4-3/0x10040003 val 0
item CFG-4-4/0x10040004 val 0
item CFG-4-9/0x10040009 val 0
item CFG-TP-TP1_ENA/0x10050007 val 1
item CFG-TP-SYNC_GNSS_TP1/0x10050008 val 1 [...]

Changing CFG,0,0,1200 to CFG,7,0,1200 would instead dump all the configuration defaults, from the Default layer (7).


Options can be placed in the UBXOPTS environment variable. UBXOPTS is processed before the CLI options.


ubxtool is written to conform to the official u-blox documentation for the u-blox binary protocol.

cgps(1), gpscat(1), gpsctl(1), gpsfake(1), xgps(1), gpsd(8),


Gary E. Miller<>

5 December 2020 The GPSD Project