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swiftnav-ros2

ROS 2 driver for Swift Navigation's GNSS/INS receivers and Starling Positioning Engine software.

Table of Contents

• Features
• ROS Topics
• Building Driver
• Launching Driver
• Driver Configuration
• GNSS Receiver Configuration
• Technical Support

Features

• Designed for ROS 2 Humble but also works with ROS 2 Foxy and Galactic
• Developed and tested on Ubuntu 22.04 (ROS 2 Humble) and Ubuntu 20.04 (ROS 2 Foxy/Galactic) platforms
• Supports Swift Navigation receivers and Starling Positioning Engine in Swift Binary Protocol (SBP)
• TCP Client and Serial communication interfaces
• SBP file playback
• SBP data logging
• Publishes ROS 2 standard and Swift Navigation proprietary topics
• Configurable time stamping
• Written in C++

ROS Topics

The driver receives Swift binary (SBP) messages (see GNSS Receiver Configuration for setting up the receiver) and publishes the following ROS topics:

• GpsFix
• NavSatFix
• TwistWithCovarianceStamped
• Baseline (proprietary)
• TimeReference
• Imu

Topic publication details are described below.

GpsFix

gps_msgs/msg/GPSFix

SBP Messages Used

• UTC TIME (ID: 259, required/optional) - UTC time of reported position. Required when timestamp_source_gnss is True.
• GPS TIME (ID: 258, required) - GPS time of reported position.
• POS LLH COV (ID: 529, required) - GNSS position with covariance.
• VEL NED COV (ID: 530, required) - GNSS velocity with covariance.
• ORIENT EULER (ID: 545, optional) - GNSS/INS orientation with estimated errors.
• DOPS (ID: 520, optional) - GNSS DOP (Dilution Of Precision) data.

Topic Publication

Topic publication depends on timestamp_source_gnss setting flag in the configuration file:

• True: The topic is published upon receiving SBP UTC TIME, GPS TIME, POS LLH COV, VEL NED COV and, if present, ORIENT EULER messages with the same TOW. The topic timestamp contains the UTC time reported by the GNSS receiver. If the UTC time is not available the current platform time is reported.
• False: The topic is published upon receiving SBP GPS TIME, POS LLH COV, VEL NED COV and, if present, ORIENT EULER messages with the same TOW. The topic timestamp contains the current platform time.

Topic Fields

NavSatFix

sensor_msgs/msg/NavSatFix

SBP Messages Used

• UTC TIME (ID: 259, required/optional) - UTC time of reported position. Required when timestamp_source_gnss is True.
• POS LLH COV (ID: 529, required) - GNSS position data with covariance.
• MEASUREMENT STATE (ID: 97, optional) - GNSS constellations data.

Topic Publication

Topic publication depends on timestamp_source_gnss setting flag in the configuration file:

• True: the topic is published upon receiving SBP UTC TIME and POS LLH COV messages with the same TOW. The topic timestamp contains the UTC time reported by the GNSS receiver. If the UTC time is not available the current platform time is reported.
• False: the topic is published upon receiving SBP POS LLH COV message. The topic timestamp contains the current platform time.

Topic Fields

TwistWithCovarianceStamped

geometry_msgs/msg/TwistWithCovarianceStamped

SBP Messages Used

• UTC TIME (ID: 259, required/optional) - UTC time of reported velocity. Required when timestamp_source_gnss is True.
• VEL NED COV (ID: 530, required) - GNSS velocity data with covariance.

Topic Publication

Topic publication depends on timestamp_source_gnss setting flag in the configuration file:

• True: the topic is published upon receiving SBP UTC TIME and VEL NED COV messages with the same TOW. The topic timestamp contains the UTC time reported by the GNSS receiver. If the UTC time is not available the current platform time is reported.
• False: the topic is published upon receiving SBP VEL NED COV message. The topic timestamp contains the current platform time.

Topic Fields

Baseline

swiftnav-ros2/msg/Baseline Proprietary message

SBP Messages Used

• UTC TIME (ID: 259, required/optional) - UTC time of reported baseline. Required when timestamp_source_gnss is True.
• BASELINE NED (ID: 524, required) - RTK baseline NED vector.

Topic Publication

Topic publication depends on timestamp_source_gnss setting flag in the configuration file:

• True: the topic is published upon receiving SBP UTC TIME and BASELINE NED messages with the same TOW. The topic timestamp contains the UTC time reported by the GNSS receiver. If the UTC time is not available the current platform time is reported.
• False: the topic is published upon receiving SBP BASELINE NED message. The topic timestamp contains the current platform time.

Topic Fields

TimeReference

sensor_msgs/msg/TimeReference

SBP Messages Used

• UTC TIME (ID: 259, required/optional) - UTC time. Required when timestamp_source_gnss is True.
• GPS TIME (ID: 258, required) - GPS time.

Topic Publication

Topic publication depends on timestamp_source_gnss setting flag in the configuration file:

• True: the topic is published upon receiving SBP UTC TIME and GPS TIME messages with the same TOW. The topic timestamp contains the UTC time reported by the GNSS receiver. If the UTC time is not available the current platform time is reported.
• False: the topic is published upon receiving SBP GPS TIME message. The topic timestamp contains the current platform time.

Topic Fields

Imu

sensor_msgs/msg/Imu

SBP Messages Used

• UTC TIME (ID: 259, required/optional) - UTC time. Required when timestamp_source_gnss is True.
• GPS TIME (ID: 258, required) - GPS time
• GNSS TIME OFFSET (ID: 65287, required/optional) - Offset of the IMU local time with respect to GNSS time. Required when the original IMU time source is a local time.
• IMU AUX (ID: 2305, required) - Auxiliary IMU data
• IMU RAW (ID: 2304, required) - Raw IMU data

Topic Publication

Topic is published upon receiving IMU RAW SBP message. Time stamp depends on timestamp_source_gnss setting flag in the configuration file:

• True: The topic timestamp contains the UTC time of the measurement computed from UTC TIME, GPS TIME, GNSS TIME OFFSET and IMU RAW SBP messages depending on original IMU time stamping source. If the UTC time is not available the current platform time is reported.
• False: The topic timestamp contains the current platform time.

Topic Fields

Building Driver

Click here if building driver in a docker

Dependencies:

• libsbp - Swift Binary Protocol library
• libserialport - Serial Port communication library

Step 1 (Install ROS 2 Humble):

Follow instructions to install ROS 2 Humble

Step 2 (Install libspb):

In any directory you wish, clone libsp v4.11.0, init the repo, make the lib and install it

  git clone https://github.com/swift-nav/libsbp.git
  cd libsbp
  git checkout v4.11.0
  cd c
  git submodule update --init --recursive
  mkdir build
  cd build
  cmake DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_STANDARD_REQUIRED=ON -DCMAKE_CXX_EXTENSIONS=OFF ../ 
  make
  sudo make install

Step 3 (Download Driver Code)

Navigate to workspace directory (e.g.: ~/workspace) and download driver source files

  cd ~/workspace
  mkdir src
  cd src
  git clone https://github.com/swift-nav/swiftnav-ros2.git

Step 4 (Install Dependencies)

Initialize environment and install dependencies

  cd ~/workspace
  source /opt/ros/humble/setup.bash
  sudo apt-get update
  sudo apt-get install libserialport-dev
  rosdep install --from-paths src --ignore-src -r -y

Step 5 (Edit Configuration)

Edit configuration file as required. See ROS 2 driver configuration for setting details.

  nano ~/workspace/src/swiftnav-ros2/config/settings.yaml

Step 6 (Build)

Initialize environment and build the driver

  cd ~/workspace
  source /opt/ros/humble/setup.bash
  colcon build

Launching Driver

Launching

Source installed driver and start it

  source install/setup.bash
  ros2 launch swiftnav_ros2_driver start.py

Viewing Topics

Swift specific SBP messages are not a part of the ROS 2 standard library, therefore the following command must be run in any terminal that is used for interfacing with this driver (e.g.: echoing the baseline message in a new terminal)

  source install/setup.bash
  ros2 topic echo /baseline

Changing Configuration

Changing the configuration file can be done in the driver source (config/settings.yaml), but the driver will need to be rebuilt. Alternatively, the configuration file can be changed in the installed directory:

  nano install/swiftnav_ros2_driver/share/swiftnav_ros2_driver/config/settings.yaml

Driver Configuration

The driver configuration is stored in the config/settings.yaml file. The following settings are available:

Connection String Description

The connection string for the serial interface has the form: BAUD RATE|PARITY|DATA BITS|STOP BITS|FLOW CONTROL

Baud Rates

1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600.

Parity

Data Bits

7 or 8

Stop Bits

1 or 2

Flow Control

GNSS Receiver Configuration

The ROS 2 driver works with Swift Navigation receivers and Starling Position Engine software using data in SBP protocol. Refer to the receiver-specific manual to configure your receiver:

• Piksi Multi
• Duro
• PGM EVK
• Starling Positioning Engine

It's recommended to dedicate one output port for ROS and output on that port only messages required by the driver. This will minimize the latency and jitter of the incoming messages, and decrease CPU load.

The driver uses the following SBP messages:

Download Swift Binary Protocol Specification

Piksi Multi / Duro Configuration Example

Piksi Multi and Duro configuration can be changed using Swift Console program. TCP Server 1 settings example:

Note: Click SAVE TO DEVICE button to memorize settings over the power cycle.

Starling Configuration Example

Starling configuration is saved in the yaml configuration file. TCP server output example:

...
  outputs:
    - name: sbp-ros2
      protocol: sbp
      type: tcp-server
      port: 55556
      max-conns: 4
      sbp:
        enabled-messages: [ 97,258,259,520,524,529,530,545,2304,2305,65287 ]
...

Technical Support

Support requests can be made by filling the Support Request Form on the Swift Navigation Support page (Support Request Form button is at the bottom of the page). A simple login is required to confirm your email address.