Ethernet interface to OxTS GPS receivers using the NCOM packet structure

Tested with the RT3000v2 receiver.

Published Topics

• gps/fix (sensor_msgs/NavSatFix) GPS position in geodetic coordinates (latitude and longitude)
• gps/vel (geometry_msgs/TwistWithCovarianceStamped) GPS velocity in ENU frame
  • linear.x Velocity due East in m/s
  • linear.y Velocity due North in m/s
  • linear.z Velocity up in m/s
• gps/odom (nav_msgs/Odometry) GPS position and heading in UTM frame, and velocity in vehicle body frame
  • pose.position.x UTM Easting in meters
  • pose.position.y UTM Northing in meters
  • pose.orientation Yaw quaternion representing the heading in UTM. Keep in mind that this UTM heading is relative to the UTM grid, which is not necessarily aligned with due East. This phenomenon is known as “grid convergence”. See Wikipedia for details.
  • twist.linear.x Local frame forward velocity of the vehicle in m/s
  • twist.linear.y Local frame lateral velocity of the vehicle in m/s
  • twist.angular.z Yaw rate of the vehicle in rad/s
• imu/data (sensor_msgs/Imu) Orientation, angular rates, and linear accelerations reported directly from the OxTS unit
• gps/pos_type (std_msgs/String) Position solution type reported by the OxTS unit (point position, differential pseudorange, RTK float, RTK integer, etc.)
• gps/nav_status (std_msgs/String) Navigation status reported by the OxTS unit. fix, vel, odom, and imu/data topics will not be published until this topic contains the string “READY”.
• gps/time_ref (sensor_msgs/TimeReference) UTC equivalent of the GPS timestamp reported by the OxTS unit.

  Parameters

• interface Restrict to single network interface, example: eth0. Default <empty>
• ip_address Local IP listen address. Default <empty>
• port Local UDP listen port. Default 3000
• frame_id_gps The frame-ID for geodetic GPS position and IMU. Default gps
• frame_id_vel The frame-ID for ENU GPS velocity. Default enu
• frame_id_odom The frame-ID for UTM odometry. Default utm

Example usage

rosrun oxford_gps_eth gps_node

OR

roslaunch oxford_gps_eth gps.launch

FAQ

I see Connected to Oxford GPS at <ip_address>:3000 , but GPS position and velocity messages are not being published.

Data is not published until the OxTS unit reports itself as being completely initialized. Drive around faster than 5 m/s for a short period of time after powering on the OxTS unit to initialize the sensor. The gps/nav_status string topic indicates the status of the initialization process. Once this string shows “READY”, the GPS position and velocity messages should start publishing.

Changelog for package oxford_gps_eth

1.2.1 (2020-08-07)

• Changes to make ntrip_forwarding.py support both Python 2 and Python 3
• Contributors: Micho Radovnikovich

1.2.0 (2020-07-06)

• Use setuptools instead of distutils for python http://wiki.ros.org/noetic/Migration#Setuptools_instead_of_Distutils
• Increase CMake minimum version to 3.0.2 to avoid warning about CMP0048 http://wiki.ros.org/noetic/Migration#Increase_required_CMake_version_to_avoid_author_warning
• Add flexibility to change GGA topic and broadcast IP for NTRIP forwarding
• Fix local frame covariance calculation
• Use cached standard deviation values instead of raw packet values because those values are multiplexed into several packets
• Add quality check of standard deviation values
• Print debugging info with ROS_DEBUG()
• Change BUILD_ASSERT() to std_assert()
• Contributors: Kevin Hallenbeck, Micho Radovnikovich

1.1.1 (2019-10-31)

• Install Python script
• Add missing rospy dependency
• Contributors: Kevin Hallenbeck, Micho Radovnikovich

1.1.0 (2019-10-28)

• Add capability to forward RTCM messages from a NTRIP caster to OxTS receivers
• Contributors: Micho Radovnikovich

1.0.0 (2018-09-07)

• Use C++11 or newer
• Publish a sensor_msgs/TimeReference message with GPS time converted to UTC
• Publish a position type string more detailed than the NavSatStatus in the fix message
• Added UTM position and heading to odometry output; Odometry twist now in local frame
• Contributors: Micho Radovnikovich, Kevin Hallenbeck

0.0.6 (2018-03-26)

• Changed default listen address from broadcast to any
• Added unit tests and rostests
• Added launch file
• Contributors: Kevin Hallenbeck

0.0.5 (2017-08-10)

• Fixed velocity utm east-north-up orientation
• Properly handle unknown covariance and fields that are not present
• Updated license for year 2017
• Updated package.xml format to version 2
• Contributors: Kevin Hallenbeck, Micho Radovnikovich

0.0.4 (2016-04-11)

• Updated license year for 2016
• Contributors: Kevin Hallenbeck

0.0.3 (2015-12-21)

• Added fix for Ubuntu Saucy
• Contributors: Kevin Hallenbeck

0.0.2 (2015-12-14)

• Added fix for Ubuntu Saucy
• Contributors: Kevin Hallenbeck

0.0.1 (2015-12-10)

• Ready for public release
• Contributors: Kevin Hallenbeck