ublox

The ublox package provides support for u-blox GPS receivers. Only the serial configuration of the driver is documented here, but TCP communication is also supported by the driver (untested).

The driver was originally written by Johannes Meyer. Changes made later are detailed in the version history below.

Options

The ublox_gps node supports the following parameters:

• device: Path to the device in /dev. Defaults to /dev/ttyUSB0.
• baudrate: Bit rate of the serial communication. Defaults to 9600.
• ublox_version: Version of device: 6,7 or 8. Defaults to 6. Please consult known issues section.
• frame_id: ROS name prepended to frames produced by the node. Defaults to gps.
• rate: Rate in Hz of measurements. Defaults to 4.
• enable_sbas: Enable satellite-based augmentation system. Defaults to false.
• enable_glonass: Enable GLONASS receiver. Defaults to false.
• enable_beidou: Enable BeiDou receiver. Defaults to false.
• enable_ppp: Enable precise-point-positioning system. Defaults to false.
• dynamic_model: See U-blox protocol spec. Defaults to portable.
• fix_mode: Type of fixes supported: 2d, 3d or both.
• dr_limit: Max time in seconds to use dead reckoning after signal is lost. Defaults to 0. (Untested as of 28/08/2014).

A sample launch file is provided in ublox_gps.launch. The two topics to which you should subscribe are /ublox_gps/fix and /ublox_gps/fix_velocity. The angular component of fix_velocity is unused.

Version history

• 0.0.4:

  • Added install targets.

• 0.0.3:

  • Added the enable_glonass, enable_beidou and enable_ppp options.
  • Added the ublox_version option. Consult known issues for important details.
  • Added numSVs field to the RQT monitor.

• 0.0.2:

  • Changed meas_rate to simply rate, which is in Hz. meas_rate is computed automatically.

• 0.0.1:

  • All topics are now published on a private node handle.
  • Velocities are published as stamped twist messages with covariance. Angular components are unsused.
  • hAcc, vAcc and sAcc are used to generate diagonal covariances.
  • Velocities use the correct convention: X-Y-Z = East-North-Up.
  • 2D or 3D fix correspond to STATUS_FIX (previously only 3D).
  • fix and fix_velocity are time-stamped synchronously, using the iTOW to check arrival times.
  • Added options for changing the CFG-NAV5 settings (see above).
  • Added support for diagnostic_updater.
  • "received ACK" messages are elevated to debug level 2.
  • Corrected issue where baudrate was not set correctly using rosparam.
  • Corrected issue where socket destructors were not called.

• 0.0.0:

  • Forked from https://github.com/tu-darmstadt-ros-pkg/ublox
  • Updated to use catkin.

Known Issues

Note on ublox_version:

ublox_version is included as a temporary workaround, resulting from the problem that the ROS serializer cannot properly parse all the ublox packets (particularly those with dynamic arrays). It is presently difficult to read the supported features of each device.

Consequently, the user should specify the version of their device in rosparam.

• Version <= 6: enable_glonass, enable_beidou are both ignored.
• Version == 7: enable_beidou is ignored.
• Version >= 8: Both options are supported.

A warning will be issued on the console indicating which options have been ignored.

FAQs

1. The ublox_gps node cannot open my device, even though I have correctly specified the path in /dev - why? Make sure you are the owner of the device, or a member of dialout group.

Links

Consult the official protocol spec for details on packets supported by ublox devices.