ROS NTRIP Client

Description

ROS node that will communicate with an NTRP caster to receive RTCM connections and publish them on a ROS topic. Also works with virtual NTRIP servers by subscribing to NMEA messages and sending them to the NTRIP server

Important Branches

There are two important branches that you may want to checkout:

• ros -- Contains ROS1 implementation for this node.
• ros2 -- Contains ROS2 implementation for this node.

Build Instructions

Building from source

1. Install ROS2 and create a workspace: Installing and Configuring Your ROS2 Environment

2. Move the entire ntrip_client folder to the your_workspace/src directory.

3. Install rosdeps for this package: rosdep install --from-paths ~/your_workspace/src --ignore-src -r -y

4. Build your workspace:

   cd ~/your_workspace
   colcon build
   source ~/your_workspace/install/setup.bash

   The source command may need to be run in each terminal prior to launching a ROS node.

Connect to a NTRIP caster or server

This is useful if you have access to an NTRIP caster or server that you want to connect to over the internet.

ros2 launch ntrip_client ntrip_client_launch.py

Optional launch parameters:

• host: Hostname or IP address of the NTRIP server to connect to.
• port: Port to connect to on the server. Default: 2101
• mountpoint: Mountpoint to connect to on the NTRIP server.
• ntrip_version: Value to use for the Ntrip-Version header in the initial HTTP request to the caster.
• authenticate: Whether to authenticate with the server, or send an unauthenticated request. If set to true, username, and password must be supplied.
• username: Username to use when authenticating with the NTRIP server. Only used if authenticate is true
• password: Password to use when authenticating with the NTRIP server. Only used if authenticate is true
• ssl: Whether to connect with SSL. cert, key, and ca_cert options will only take effect if this is true
• cert: If the NTRIP caster is configured to use cert based authentication, you can use this option to specify the client certificate
• key: If the NTRIP caster is configured to use cert based authentication, you can use this option to specify the private key
• ca_cert: If the NTRIP caster uses self signed certs, or you need to use a different CA chain, this option can be used to specify a CA file
• rtcm_message_packege: Changes the type of ROS RTCM message published by this node. Defaults to mavros_msgs, but also supports rtcm_msgs

Connect to a NTRIP "device"

This is useful if you do not have an internet connection, but do have an NTRIP "device" that you want to receive connections from, such as the MicroStrain 3DM-RTK.

ros2 launch ntrip_client ntrip_serial_device_launch.py

Optional launch parameters:

• port: Serial port that the device is connected on.
• baudrate: Baudrate to connect to the serial port at. Default 115200
• rtcm_message_packege: Changes the type of ROS RTCM message published by this node. Defaults to mavros_msgs, but also supports rtcm_msgs

Topics

This node currently only has three topics of interest:

• /rtcm: This node will publish the RTCM corrections received from the server to this topic as RTCM messages. These messages can be consumed by nodes such as the microstrain_inertial_driver
  • NOTE: The type of message can be switched between mavros_msgs/RTCM and rtcm_msgs/Message using the rtcm_message_package parameter
• /nmea: This node will subscribe on this topic and receive NMEA sentence messages which it will forward to the NTRIP server. This is always needed when using a virtual NTRIP server or an NTRIP device
• /fix: This serves the same exact purpose as /nmea, but facilitates receiving global position that is not in NMEA format

License

ntrip_client is released under the MIT License - see the LICENSE file in the source distribution.

Copyright (c) 2024, MicroStrain by HBK