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Unitree Go2 RTK: Add RTK GPS to the Go2 EDU with ROS 2

Unitree lists GPS but no RTK for the Go2. Add an RTK GNSS receiver to a Go2 EDU and stream RTKdata NTRIP corrections to it with the ROS 2 NTRIP client.

According to Unitree's specification, the Unitree Go2 robot dog has no RTK: the Go2 PRO, X and EDU list a "4G Module(with GPS)", and Unitree documents neither RTK nor a developer interface for that GPS. A Unitree Go2 RTK setup uses an external RTK GNSS receiver on a Go2 EDU: connect the receiver by USB to a Linux companion computer with ROS 2 Humble (or Jazzy), run the receiver driver and the ROS 2 NTRIP client (ntrip_client) there, and connect ntrip_client to RTKdata with the host for your region (rtk.rtkdata.com for North America, eu.rtkdata.com for Europe or aus.rtkdata.com for Australia), port 2101, the AUTO mountpoint and your RTK credentials. ntrip_client sends the receiver's own GGA sentences to the caster and publishes the corrections on /rtcm, where the driver passes them to the receiver.

The Go2 statements on this page follow Unitree's Go2 developer documentation (About Go2, FAQ, Payload, Quick Start and Network, plus the pages on the expansion dock, SLAM, ROS 2, the Go2-W and Unitree's Industrial-grade Navigation, read in September 2026). The ROS 2 steps follow the ROS 2 NTRIP Client guide, which has the complete parameter files, and the source code of ntrip_client 1.4.1 and of the ublox driver on its ros2 branch (release 3.0.0), the current versions in September 2026.

These are the values for ntrip_client on the computer that runs the GNSS stack; the names in code format are its parameters. Choose the server closest to your work area. All three servers share the same base station network; the difference is routing latency, see NTRIP Server Settings.

  • Host (domain) in host: rtk.rtkdata.com

  • Host (IP fallback): 13.56.117.10, only if the computer cannot resolve the hostname

  • Port: 2101, in port

  • Username / Password: From RTK Credentials in your account dashboard, not your website login, in username and password with authenticate: true

  • Mountpoint (ALL CAPS): AUTO (recommended), or AUTO_WGS84, AUTO_ITRF2020, AUTO_ITRF2014, in mountpoint

  • Host (domain) in host: eu.rtkdata.com

  • Host (IP fallback): 3.73.41.96, only if the computer cannot resolve the hostname

  • Port: 2101, in port

  • Username / Password: From RTK Credentials in your account dashboard, not your website login, in username and password with authenticate: true

  • Mountpoint (ALL CAPS): AUTO (recommended), or AUTO_WGS84, AUTO_ITRF2020, AUTO_ITRF2014, in mountpoint

  • Host (domain) in host: aus.rtkdata.com

  • Host (IP fallback): 54.206.56.130, only if the computer cannot resolve the hostname

  • Port: 2101, in port

  • Username / Password: From RTK Credentials in your account dashboard, not your website login, in username and password with authenticate: true

  • Mountpoint (ALL CAPS): AUTO (recommended), or AUTO_WGS84, AUTO_ITRF2020, AUTO_ITRF2014, in mountpoint

Field
Value

host, North America

rtk.rtkdata.com, IP fallback 13.56.117.10

host, Europe

eu.rtkdata.com, IP fallback 3.73.41.96

host, Australia

aus.rtkdata.com, IP fallback 54.206.56.130

port

2101

mountpoint

AUTO (recommended), or AUTO_ITRF2020, AUTO_ITRF2014, AUTO_WGS84

authenticate

true

username and password

From RTK Credentials in your account dashboard. The username starts with rtk and is not your website login.

rtcm_message_package

rtcm_msgs, the message type the ublox driver reads on /rtcm

GGA to the caster

The receiver's own NMEA sentences on /nmea, from ublox_gps with publish.nmea: true and rate: 1.0

Computer address on the Go2 network

An address in 192.168.123.x, for example 192.168.123.222, never 192.168.123.161

  • Enter only the hostname or the IP address in host, without http:// and without :2101. ntrip_client opens a TCP connection to host on port.

  • Mountpoint names are case sensitive: AUTO in capitals.

  • One data stream allows one connection at a time. A second robot, a drone or a rover running at the same time needs its own data stream, see Account & Credentials.

Requirements

  • Unitree Go2 EDU. Unitree states: "Only EDU or above versions can be developed". The optional expansion dock is not needed for this setup.

  • RTK GNSS receiver with a USB port that accepts RTCM 3 corrections with MSM4 messages and 1005. RTKdata streams RTCM 3.2 with MSM4 messages (1074, 1084, 1094, 1114, 1124, 1134) and 1005. Example: the u-blox ZED-F9P; u-blox states that its rover needs base station observations as MSM4 or MSM7 messages and the station position as 1005 or 1006 to attempt ambiguity fixes (ZED-F9P Integration Manual, section 3.1.5.4). The same section adds that GLONASS ambiguities need RTCM 1230 or 1033. 1230 comes from the base station, and most RTKdata base stations do not send it, so GLONASS does not contribute to the RTK fix. GPS, Galileo and BeiDou are not affected.

  • Multi-frequency GNSS antenna with the ground plane its manufacturer specifies

  • Linux companion computer with Ubuntu 22.04 and ROS 2 Humble, which Unitree's unitree_ros2 marks as recommended, or Ubuntu 24.04 and ROS 2 Jazzy, with a USB port for the receiver and an Ethernet port for the Go2

  • Internet for the companion computer with outbound TCP on port 2101, for example over a USB Wi-Fi adapter or an LTE modem

  • RTKdata account with active RTK credentials (username starts with rtk), with one data stream per robot connected at the same time

  • RTKdata coverage at your site: check the coverage map before you go out

Don't have an RTKdata.com account yet? Start 30-day Free Trial or View Pricing

Does the Unitree Go2 have RTK?

No: according to Unitree's Go2 specification, no Go2 model has RTK; the PRO, X and EDU have a "4G Module(with GPS)", Unitree documents no RTK and no developer interface for the Go2 GPS, and RTK with RTKdata corrections needs an external RTK GNSS receiver on a Go2 EDU.

  • Unitree's About Go2 product list shows the "4G Module(with GPS)" as "No" on the AIR and "Yes, CN/GB" on the PRO, X and EDU. The list has no RTK entry for any Go2 model.

  • Unitree's SDK and ROS 2 package define no GNSS message type: the Go2 message types in unitree_sdk2 (include/unitree/idl/go2) and in the unitree_go package of unitree_ros2 include no GNSS type. There is therefore no documented Go2 topic with a GNSS position, such as a sensor_msgs/msg/NavSatFix, that could give ntrip_client a position for GGA.

  • Unitree's own RTK is an optional "dual-antenna RTK module" for its Industrial-grade Navigation software, together with a 5G module, a "differential account (provided by the user or Unitree)" and a data SIM card. The software's list of compatible robot models names the B2, B2W, G1-EDU, A2 PRO and A2-W PRO as currently supported and the As2-EDU under extended support, and its specification table lists RTK-integrated positioning for the B2/B2W and A2/A2W. The Go2 is on neither list.

For RTK on a Go2, add an external RTK receiver with its own antenna, as described on this page.

Which Go2 models can take an external RTK receiver?

Of the Go2 AIR, PRO, X and EDU, only the Go2 EDU has documented interfaces for an external RTK receiver: Unitree reserves the RJ45, DC 28.8V and SBUS interfaces for the EDU, offers the optional NVIDIA Jetson Orin module only on the EDU, and lists secondary development as "Support" for the EDU and as "Basic support" for the X. The Go2-W has the same interfaces, but this guide does not cover it.

Unitree specification
AIR
PRO
X
EDU

Secondary development

No

No

Basic support

Support

RJ45, DC 28.8V and SBUS interfaces

No

No

No, exclusive to the EDU

Yes

High computing power module

No

No

No

Optional NVIDIA Jetson Orin (40 to 100 Tops)

4G Module(with GPS)

No

Yes, CN/GB

Yes, CN/GB

Yes, CN/GB

Unitree's note on the electrical interfaces reads: "The Go2 Pro and Go2 Air versions do not support any of the extended electrical interfaces, including the SBUS port, DC 28.8V power output, and the Ethernet (RJ45) interface. These interfaces are exclusive to the Go2 EDU version."

  • The Unitree FAQ states: "Only EDU or above versions can be developed, other versions such as PRO and AIR versions do not open the secondary development interface".

  • For the X, the product list shows "Basic support" for secondary development but no computing module, and the note above names the extended interfaces as exclusive to the EDU.

  • For the Go2-W, Unitree's About Go2-W page lists "Secondary development" as "Yes" and the same RJ45, DC 28.8V and SBUS interfaces.

Where should the GNSS stack run: expansion dock or companion computer?

Run the receiver driver and ntrip_client for RTKdata on a companion computer with ROS 2 Humble or Jazzy that is connected to the Go2 EDU by Ethernet, because Unitree's documentation shows the expansion dock with Ubuntu 20.04 and ROS 2 Foxy, and the Foxy packages in the ROS package repository include no u-blox driver that takes corrections from a ROS topic.

  • Unitree's screenshot of the dock login shows "Ubuntu 20.04.6 LTS" on "aarch64" and the prompt ros:foxy(1) noetic(2) ?.

  • For Foxy, the ROS package repository has ntrip_client 1.2.0, which publishes corrections only as mavros_msgs/RTCM and takes GGA only from nmea, and ublox_gps 2.1.0, which has no RTCM input. ublox_dgnss is not available for Foxy.

  • On a companion computer with Humble or Jazzy, ntrip_client 1.4.1 installs from apt, and the ublox driver built from its ros2 branch subscribes to /rtcm.

  • If the same computer also talks to the Go2 through unitree_ros2, prefer Humble: Unitree lists Ubuntu 20.04 with Foxy and Ubuntu 22.04 with Humble as the tested systems for its ROS 2 package and marks Humble as recommended.

  • Connect the companion computer to the Go2 by Ethernet cable. The Unitree FAQ states: "Go2 only supports wired connection for development." Use the RJ45 interface on the back of the Go2 EDU or, with the expansion dock fitted, the dock's second RJ45 port, which Unitree describes as "externally connected to the user".

  • Give the computer's Ethernet adapter an address in the 192.168.123.x subnet, for example 192.168.123.222. Unitree does not allow 192.168.123.161 on the computer, because it is the address of the Go2's built-in computer. ping 192.168.123.161 tests the link.

Without the ROS 2 NTRIP client: use a receiver with its own NTRIP client and its own internet connection; the robot computer then only reads the position from the receiver. For example, enter the RTKdata values in the NTRIP client of a Septentrio receiver through its web interface, as described in the Septentrio mosaic-X5 guide. On ROS 2, septentrio_gnss_driver can write them into the receiver through rtk_settings.ntrip_1 instead. Set send_gga to sec1 there, because in auto mode the receiver sends GGA only if the caster requests it, according to the driver documentation. The Septentrio tab of the ROS 2 NTRIP Client guide covers driver version 1.4.8 for Humble and Jazzy. For Foxy, which the expansion dock runs, apt has version 1.2.3, which starts with other launch files: its README gives ros2 launch septentrio_gnss_driver rover_node.py, and the launch file takes the full path of your parameter file in path_to_config.

Only if you use the expansion dock: do not activate a ROS environment in a terminal where you run Unitree's SLAM or SDK2 tools. Unitree states that these tools "require CycloneDDS and cannot be launched in an environment where ROS/ROS2 has been initialized". Press Enter at the prompt ros:foxy(1) noetic(2) ? in that terminal, and run ROS 2 nodes in a separate terminal.

How do you mount and power the RTK receiver on the Go2?

Mount the antenna at the highest point of the Go2 with open sky, on the ground plane its manufacturer specifies and away from the computer, cameras, LiDAR and radios, and power the receiver over USB from the companion computer or from a 12 V or 5 V output of the expansion dock, not from the DC 28.8V back output.

Antenna position

  • Place the antenna where nothing on the robot blocks the sky. The best conditions have no obstructions above 15 degrees elevation, see Accuracy Expectations.

  • Use the ground plane the antenna manufacturer specifies. For example, u-blox measures the ANN-MB antenna on a 15 cm ground plane, gives its phase center offset for a circular ground plane of 120 mm diameter and states: "Any change in ground plane size or shape may affect the phase center offset."

  • Keep the antenna away from the dock computer, the cameras, the LiDAR and the Go2's 4G and Wi-Fi radios. u-blox warns that "all types of digital equipment, such as PCs, digital cameras, LCD screens, etc. tend to emit a broad frequency spectrum up to several GHz", and that wireless systems such as LTE, WLAN and Bluetooth close to the GNSS antenna can interfere (ZED-F9P Integration Manual, section 4.6.1).

  • Mounting points: the expansion dock has guide rails, with the dimensions under "Rail size" on Unitree's Payload page, and Unitree fixes its servo arm to these rails with a square nut and "M4*10 internal hexagon screws". The Go2 EDU back has load mounting holes, shown in Unitree's "Back load installation hole map".

  • Weight: Unitree gives the Go2 EDU a load of about 8 kg, with a limit of about 12 kg. The receiver, antenna, mounts, companion computer and LTE modem on the robot all count toward it.

Power and data

Power source (Unitree specification)
Output
Use for a receiver

Expansion dock, XT30U-F power interface

12 V, 3 A and 5 V, 3 A, one output each for the user

Receivers with a 12 V or 5 V power input

Expansion dock, USB-Type A and the two USB-C ports

5 V/1 A on USB-Type A ("Only USB host"), 5 V/3 A and 5 V/2 A on the USB-C ports

Not for this setup: a receiver on these ports connects to the dock computer, not to the companion computer that runs the driver

Go2 EDU back, power interface

DC 28.8V, the battery voltage (Go2 supply voltage 28 V to 33.6 V)

Only devices rated for this input range

  • Connect the receiver by USB to the companion computer, which runs its driver. ublox_gps opens /dev/ttyACM0 by default (parameter device).

  • If you power a companion computer from the Go2, the same applies: the back output carries the battery voltage.

How does the Go2 get internet for RTK corrections?

Give the computer that runs ntrip_client its own internet connection to RTKdata, for example over a USB Wi-Fi adapter or an LTE modem, with outbound TCP on port 2101, because Unitree does not document that the expansion dock or a companion computer can use the Go2's Wi-Fi or 4G connection.

  • The expansion dock has Wi-Fi only with an "additional wireless network card", according to Unitree's SLAM documentation.

  • On the Go2's 4G channel, "some restrictions are placed on accessing domain names to prevent traffic consumption", according to Unitree's network documentation.

  • For the "non-Chinese mainland version" of the Go2, Unitree states that the 4G function "will only support 43 European countries (except Ukraine), and some Asian regions".

  • RTKdata needs outbound TCP on port 2101. Firewalls, VPNs and some mobile carriers can block this port, see Troubleshooting & FAQ.

  • Use a stable connection: RTKdata recommends a stable 4G or 5G connection and no public Wi-Fi or VPN, see Accuracy Expectations.

How do you set up RTKdata on a Go2 EDU with ROS 2?

Mount the receiver on a Go2 EDU, connect it by USB to a companion computer with internet, install ntrip_client and the ublox driver there, create the two parameter files from the ROS 2 NTRIP Client guide, connect ntrip_client to RTKdata with the host for your region, port 2101 and AUTO, start both nodes and check /nmea, /rtcm and the fix status. The steps use a u-blox ZED-F9P and ROS 2 Humble as the example.

1

Check the Go2 model

Check that the robot is a Go2 EDU: the RJ45, DC 28.8V and SBUS interfaces on its back exist only on the EDU. On the AIR and PRO, Unitree opens no secondary development interface.

2

Mount the receiver and antenna

Fit the receiver to the dock rails or the back mounting holes, and the antenna at the highest point with its ground plane, away from the computer, cameras, LiDAR and radios, as described in How do you mount and power the RTK receiver on the Go2? above.

3

Connect USB, power and Ethernet

  1. Connect the receiver by USB to the companion computer. ublox_gps expects it at /dev/ttyACM0 unless you set another device.

  2. If the receiver needs its own supply, use a 12 V or 5 V output of the expansion dock, not the DC 28.8V back output.

  3. Connect the companion computer to the Go2 by Ethernet cable, set its adapter to an address such as 192.168.123.222 and test the link:

4

Give the computer internet

Connect the companion computer to the internet over its own uplink, for example a USB Wi-Fi adapter or an LTE modem, and make sure that outbound TCP on port 2101 is open.

5

Install ntrip_client and the ublox driver

Install ntrip_client from the ROS 2 package repository (on Jazzy, the package is ros-jazzy-ntrip-client):

Build the ublox driver from its ros2 branch in a ROS 2 workspace at ~/ros2_ws. The ros-humble-ublox-gps package from apt (2.3.0) has no RTCM input; the ros2 branch (release 3.0.0) subscribes to /rtcm and publishes the receiver's NMEA sentences on /nmea.

If the computer has no ROS 2 build tools yet, install them and set up rosdep once:

Then create the workspace and build the driver. On Jazzy, source /opt/ros/jazzy/setup.bash instead:

6

Create the two parameter files

Create ~/ublox_rover.yaml for the receiver driver and ~/rtkdata_ntrip.yaml for ntrip_client with the content from the ROS 2 NTRIP Client guide: ublox_rover.yaml from its tab u-blox ZED-F9P (ublox_gps) and rtkdata_ntrip.yaml from its step Create the parameter file, for your region. The guide also explains why these values differ from the defaults. The values that matter:

File
Parameter
Value

ublox_rover.yaml

tmode3

0, rover mode. The zed_f9p.yaml that comes with the driver sets 1, survey-in, which makes the receiver a base

ublox_rover.yaml

gnss.gps, gnss.glonass, gnss.galileo, gnss.beidou, gnss.qzss

true. With config_on_startup on, the driver writes these values to the receiver, and only gnss.gps defaults to true

ublox_rover.yaml

rate

1.0 (Hz), in line with the GGA rate of 1 Hz that RTKdata recommends

ublox_rover.yaml

publish.nmea

true, the GGA source for ntrip_client

rtkdata_ntrip.yaml

host, port, mountpoint

The host for your region, 2101, AUTO

rtkdata_ntrip.yaml

authenticate, username, password

true and your RTK credentials

rtkdata_ntrip.yaml

rtcm_message_package

rtcm_msgs

rtkdata_ntrip.yaml

nmea_max_length

128

rtkdata_ntrip.yaml

rtcm_timeout_seconds

15

7

Start both nodes and check the fix

Start each node in its own terminal with the workspace sourced (source ~/ros2_ws/install/setup.bash). If the computer also talks to the Go2 through unitree_ros2, source ~/unitree_ros2/setup.sh before the workspace, see ROS 2 distribution, RMW and time stamps below. Start the driver first and wait until the receiver has a position (status.status on /ublox_gps_node/fix is no longer -1), then start ntrip_client:

Then check the three stages:

  1. /nmea shows GGA sentences from the receiver. Without them, AUTO has no position and sends no corrections.

  2. ntrip_client logs Connected to http://eu.rtkdata.com:2101/AUTO (with your host) once the login works. ros2 topic info /rtcm --verbose lists ntrip_client as a publisher and ublox_gps_node as a subscriber.

  3. On /ublox_gps_node/fix, status.status is 2 (STATUS_GBAS_FIX) when the receiver has a fixed carrier phase solution, which is RTK Fixed. 0 is a fix without fixed ambiguities, which includes RTK Float, and -1 is no fix.

AUTO needs your position. The AUTO mountpoint chooses the base station from the position the receiver sends as NMEA GGA. On the Go2, only the external receiver can provide it: ntrip_client sends the sentences that arrive on /nmea to the caster, and the Go2 has no documented GNSS topic. Without a position, the login works but no corrections arrive, see NTRIP & GGA Essentials. Wait outside with open sky until the receiver has a position of its own.

How do you use RTK positions for Go2 navigation?

Keep waypoints and maps in the datum that your RTKdata mountpoint delivers, plan a source of absolute heading, and run the GNSS nodes with the same ROS 2 distribution and RMW implementation as the nodes that talk to the Go2.

Datum and heights with AUTO

  • AUTO delivers your region's datum, chosen from your GGA position: for example NAD83(2011), epoch 2010.0, in the USA; NAD83(CSRS)v7, epoch 2010.0, in Canada; ETRS89 (realization ETRF2000), epoch 2010.0, in Europe; and GDA2020, epoch 2020.0, in Australia. For regions not listed, AUTO falls back to WGS84(G2139) at the mid-year epoch. The datum for every region is listed in Coordinate Systems & Datums.

  • AUTO_ITRF2020 and AUTO_ITRF2014 deliver ITRF2020 and ITRF2014 at the current epoch, and AUTO_WGS84 delivers WGS84(G2139) at the mid-year epoch.

  • u-blox states that the rover coordinates "will be expressed in the datum used by the RTCM correction provider". With AUTO, latitude and longitude on /ublox_gps_node/fix are therefore in the regional datum, although sensor_msgs/msg/NavSatFix is "Specified using the WGS 84 reference ellipsoid" and has no datum field.

  • For waypoints from web maps or other WGS 84 sources, use AUTO_WGS84 or AUTO_ITRF2020. For waypoints surveyed with RTK on AUTO, stay on AUTO. A steady offset of 50 cm to 1 m usually means mixed datums, see Why Your Coordinates May Be Offset.

  • Heights are ellipsoidal, see Understanding Heights.

  • u-blox states that the ZED-F9P stops using RTCM corrections older than 60 s (the default, set with CFG-NAVSPG-CONSTR_DGNSSTO) and drops back to a 3D or 3D/DGNSS mode, and that the reference frame of the output position then switches from that of the correction data to that of the standard position solution. With AUTO, the position can then shift by the datum difference, so use a position for navigation only while status.status is 2.

Absolute heading and robot_localization

  • The Nav2 documentation states: "When using robot_localization with GPS, measuring absolute orientation is mandatory."

  • The Go2 IMU message unitree_go/msg/IMUState has the fields quaternion, gyroscope, accelerometer, rpy and temperature, and no magnetometer field. Plan a source of absolute heading; Nav2 names "IMUs with magnetometers, dual GPS systems or matching techniques over a known map".

  • In its source code (robot_localization 3.5.4 on Humble, 3.8.3 on Jazzy), navsat_transform_node subscribes to gps/fix (sensor_msgs/msg/NavSatFix), odometry/filtered (nav_msgs/msg/Odometry) and, with its default parameters, imu (sensor_msgs/msg/Imu) for the heading. Remap gps/fix to /ublox_gps_node/fix.

  • The Go2 state topics that Unitree documents for ROS 2, sportmodestate and lowstate, carry Unitree's own messages unitree_go/msg/SportModeState and unitree_go/msg/LowState, not sensor_msgs/msg/Imu or nav_msgs/msg/Odometry. To use Go2 data in robot_localization, convert it with a node of your own first.

ROS 2 distribution, RMW and time stamps

  • Unitree's unitree_ros2 talks to the Go2 over CycloneDDS: its setup.sh sets RMW_IMPLEMENTATION=rmw_cyclonedds_cpp and a CYCLONEDDS_URI with the network interface that is connected to the Go2.

  • The ROS 2 documentation states: "Nodes are not guaranteed to be able to communicate across distributions", and communication across RMW vendors within one distribution is not guaranteed either. Run the GNSS nodes with the same distribution and RMW implementation as the Go2 connection.

  • If the companion computer talks to the Go2 through unitree_ros2, run the GNSS nodes in terminals with the same environment as the Go2 connection. As the unitree_ros2 README describes, replace foxy with your ROS 2 distribution and enp3s0 with the network interface connected to the Go2 in ~/unitree_ros2/setup.sh. Then source it before the GNSS workspace in each terminal:

  • ublox_gps stamps /ublox_gps_node/fix with the receiver's UTC time when it is valid and with the computer's ROS time otherwise. Before you fuse the fix with Go2 odometry, for example in robot_localization, check that the time stamps of the Go2 topics and of the fix agree.

Troubleshooting

Problem
Cause
Fix

No GPS, GNSS or fix topic from the Go2

Unitree's SDK and ROS 2 package define no GNSS message type, and Unitree documents no developer interface for the Go2 GPS

Add an external RTK receiver with its own ROS 2 driver, as described on this page

Unable to connect socket to server at http://<host>:2101 in the ntrip_client log

The computer that runs ntrip_client has no internet, cannot resolve the hostname, or port 2101 is blocked

Give the computer its own uplink (USB Wi-Fi adapter or LTE modem), allow outbound TCP on port 2101, and try the IP fallback for your region in host. ntrip_client exits after a failed first connection: start it again once the uplink is up, or start it from a launch file with respawn=True as shown in the ROS 2 NTRIP Client guide

On the expansion dock, apt installs ros-foxy-ntrip-client 1.2.0 and ros-foxy-ublox-gps 2.1.0, and the receiver gets no corrections

The dock runs Ubuntu 20.04 with ROS 2 Foxy. ntrip_client 1.2.0 publishes only mavros_msgs/RTCM, and ublox_gps 2.1.0 has no RTCM input

Run the GNSS stack on a companion computer with Humble or Jazzy, or use a receiver with its own NTRIP client

ping 192.168.123.161 fails from the companion computer

The Ethernet adapter has no address in the 192.168.123.x subnet, or the cable is not connected

Set an address such as 192.168.123.222 on the adapter connected to the Go2 and check the cable. Never set 192.168.123.161 on the computer

Receiver connected to the DC 28.8V back output

This output carries the battery voltage, 28 V to 33.6 V

Power the receiver over USB from the companion computer or from a 12 V or 5 V output of the expansion dock, unless it is rated for this input range

Corrections drop again and again while a second robot or a drone is running

Both devices share one data stream, for example through the same RTK credentials

One data stream per device connected at the same time, see Account & Credentials

ntrip_client logs Connected to ..., but no corrections arrive on /rtcm

No GGA reaches the caster: /nmea stays empty, for example because publish.nmea is off or the receiver outputs no NMEA

Check ros2 topic echo /nmea, then the troubleshooting table of the ROS 2 NTRIP Client guide

/rtcm carries data, but status.status never reaches 2

The driver does not subscribe to /rtcm, for example ublox_gps 2.3.0 from apt, or constellations are switched off

Check that ros2 topic info /rtcm --verbose lists the driver as a subscriber, use the ros2 branch of ublox and set all gnss.* values to true

Position offset against waypoints from a web map

AUTO delivers the regional datum, while the web map uses WGS 84

Use AUTO_WGS84 or AUTO_ITRF2020 for WGS 84 waypoints, or survey the waypoints on AUTO

No Wi-Fi on the expansion dock

The dock needs an "additional wireless network card"

Add a USB Wi-Fi adapter or use an LTE modem

Unitree SLAM or SDK2 tools on the dock do not start

A ROS environment is active in that terminal. Unitree: these tools "cannot be launched in an environment where ROS/ROS2 has been initialized"

Press Enter at ros:foxy(1) noetic(2) ? in that terminal and run ROS 2 nodes in another one

Position shifts after a longer loss of corrections

The ZED-F9P stops using corrections older than 60 s, drops back to a 3D or 3D/DGNSS mode and outputs its position in the reference frame of the standard solution

Keep a stable uplink, and use a position for navigation only while status.status is 2

For connection problems that are not specific to the Go2, see Common Connection Issues.

Frequently asked questions

Can the Go2's built-in GPS be used for RTK?

No, not with any documented interface: the Unitree Go2 GPS is part of the "4G Module(with GPS)" of the PRO, X and EDU, and Unitree documents no RTK and no developer interface for it. Unitree's SDK and ROS 2 package define no GNSS message type, so there is no documented Go2 topic that could give ntrip_client a position for GGA or pass RTK corrections to the GPS. Use an external RTK receiver with its own antenna and connect it to RTKdata as described on this page.

Does the Go2 Air or Pro work with an external RTK receiver?

Not through a documented interface: Unitree states that "Only EDU or above versions can be developed" and that the PRO and AIR "do not open the secondary development interface". According to Unitree, the RJ45, DC 28.8V and SBUS interfaces are exclusive to the Go2 EDU. This guide covers RTKdata corrections on the Go2 EDU.

Can I run the ROS 2 NTRIP client on the Go2 expansion dock?

Not for the RTKdata setup on this page: Unitree's documentation shows the dock with Ubuntu 20.04 and ROS 2 Foxy, where the ROS package repository offers ntrip_client 1.2.0, which publishes corrections only as mavros_msgs/RTCM, and ublox_gps 2.1.0, which has no RTCM input. This guide runs the GNSS stack on a companion computer with Humble or Jazzy instead, where ntrip_client 1.4.1 connects to RTKdata on port 2101 with the AUTO mountpoint, and does not cover building newer versions on the dock. On the dock, a receiver with its own NTRIP client is the alternative, for example a Septentrio receiver set up in its web interface or with septentrio_gnss_driver 1.2.3, see Without the ROS 2 NTRIP client above.

Does Unitree offer an RTK module for the Go2?

Not according to Unitree's documentation: Unitree's optional "dual-antenna RTK module" belongs to its Industrial-grade Navigation software, whose list of currently supported robot models names the B2, B2W, G1-EDU, A2 PRO and A2-W PRO, not the Go2. For RTK on a Go2 EDU, add an external RTK receiver and stream RTKdata corrections to it with the ROS 2 NTRIP client.

Do I need one RTKdata data stream per robot?

Yes, one RTKdata data stream for each robot that is connected at the same time. One data stream allows one connection at a time, and two devices on the same data stream keep disconnecting each other, so the fix status keeps cycling between FIX, FLOAT and SINGLE. Robots that run one after another can share one set of credentials. Depending on how the account was provisioned, extra data streams come as separate credentials or as one set of credentials with several connections, see Account & Credentials.

Quick reference

  1. Go2 EDU only. Add an external RTK receiver with USB and a multi-frequency antenna, for example a u-blox ZED-F9P, with the antenna at the highest point on a ground plane, away from computers, cameras and radios.

  2. Power the receiver over USB from the companion computer or from a 12 V or 5 V output of the expansion dock, not from the DC 28.8V back output.

  3. Companion computer with Ubuntu 22.04 and ROS 2 Humble (or 24.04 and Jazzy), connected to the Go2 by Ethernet with an address such as 192.168.123.222 (never 192.168.123.161, the address of the Go2's built-in computer), and its own internet with outbound TCP on port 2101.

  4. sudo apt install ros-humble-ntrip-client, and the ublox driver from its ros2 branch, built with colcon.

  5. ublox_rover.yaml: tmode3: 0, all gnss.* values true, rate: 1.0, publish.nmea: true.

  6. rtkdata_ntrip.yaml: host rtk.rtkdata.com, eu.rtkdata.com or aus.rtkdata.com (IP fallback 13.56.117.10, 3.73.41.96 or 54.206.56.130), port: 2101, mountpoint: AUTO, authenticate: true, your RTK credentials, rtcm_message_package: rtcm_msgs, nmea_max_length: 128, rtcm_timeout_seconds: 15.

  7. Start the driver, wait for a position, then start ntrip_client. Check GGA on /nmea, the driver as a subscriber in ros2 topic info /rtcm --verbose, and status.status 2 on /ublox_gps_node/fix for RTK Fixed.

  8. For navigation, keep waypoints and fixes in one datum and add a source of absolute heading. If the computer also uses unitree_ros2, start the GNSS nodes after source ~/unitree_ros2/setup.sh.

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