Swift Nav driver for ROS2

Contents

• Overview
• Scope
• Dependencies
• Building
• Params
• Settings
• Run
• Topics
• Further reading

Overview

This is a C++ ROS driver for Swift Nav Piksi Multi GPS / GNSS Receivers. The code is based on offical Swiftnav libswiftnav C example.

Scope

The current version supports (not tested elsewhere):

• Ubuntu 20.04
• ROS2 Foxy
• Colcon tools
• Communication over serial

Dependencies

Libsbp

• libsbp (Swift binary protocol library) C client library from GitHub: https://github.com/swift-nav/libsbp
• Install libserialport: https://github.com/sigrokproject/libserialport

Installing dependencies with script

cd sdk
sudo ./sdk-install

Building

colcon build --packages-select swift_nav_driver

Params

In param/defaults.param.yaml file:

• baudrate - driver was tested with 230400, default value set on Piksi is 115200
• port - must be set port name found in /dev for the device
• frame_id - frame id for the device, default value: "gnss"

Settings in Piksi console

In Swift Console software:

• set imu rate
• enable and login to ntrip provider
• in used uart settings make sure that needed messages are enabled
  • msg_pos_llh_cov_t - 0x0211 - 529
  • msg_vel_ned_cov_t - 0x0212 - 530
  • msg_gps_time_t - 0x0102 - 258
  • msg_imu_raw_t - 0x0900 - 2304/20 (number after / divides rate of set imu rate by int number)

Run

ros2 launch swift_nav_driver swift_nav_driver.launch.py

Alternatively you can use a ros2 run

ros2 run swift_nav_driver swift_nav_node_exe

Topics

Driver publishes the following topics and [types]:

• /gnss/nav_fix Type: sensor_msgs/msg/NavSatFix
• /gnss/nav_speed Type: geometry_msgs/msg/TwistWithCovarianceStamped
• /gnss/nav_time Type: sensor_msgs/msg/TimeReference
• /gnss/imu Type: sensor_msgs/msg/Imu

Further reading

• Libswiftnav: https://github.com/swift-nav/libswiftnav
• Libsbp documentation: https://swift-nav.github.io/libsbp/c/build/docs/html