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Overview

ROS package for SBG Systems IMU.

The driver allows the user to configure the IMU (if possible, according to the device), to receive messages from the Sbg message protocol, publish ROS standard messages , and to calibrate the magnetometers.

Installation

Installation from packages

User can install the sbg_ros_driver through the standard ROS installation system.

sudo apt-get install ros-$ROS_DISTRO-sbg-driver

Installation from sources

1. Clone the repository (use a Release version) https://github.com/SBG-Systems/sbg_ros_driver

2. Build using the normal ROS catkin build system

Usage

Enable communication with the SBG device

To be able to communicate with the device, be sure that your user is part of the dialout group. Once added, restart your machine to save and apply the changes.

sudo adduser $USER dialout

Afterwards, detect the port where your SBG device is connected (e.g. /dev/ttyUSB0) using

dmesg | grep tty

and edit sbg_device_uart_default.yaml accordingly or (recommended) define a udev rule (e.g. pointing to /dev/sbg)

Ros node for IMUs data

Run the ros node to receive messages from the SBG IMU.

Config files are available for uart or udp connection. Users should properly define the device parameters.

roslaunch sbg_driver sbg_device.launch

Ros node for magnetometers calibration

roslaunch sbg_driver sbg_device_mag_calibration.launch

Configuration files

Default config files

sbg_device_uart_default.yaml

This config file is the default one for Uart connection with the device. It does not configure the device through the ROS node, so it has to be previously configured (manually or with the ROS node).

It define a few outputs for the device :

• /sbg/imu_data, /sbg/ekf_quat at 25Hz,
• ROS standard outputs /imu/data, /imu/velocity, /imu/temp at 25Hz,
• /sbg/status; /sbg/utc_time, /imu/utc_ref at 1 Hz.

sbg_device_udp_default.yaml

This config file is the default one for an Udp connection with the device. It does not configure the device through the ROS node, so it has to be previously configured (manually or with the ROS node).

It defines a few outputs for the device :

• /sbg/imu_data, /sbg/ekf_quat at 25Hz
• ROS standard outputs /imu/data, /imu/velocity, /imu/temp at 25Hz
• /sbg/status, /sbg/utc_time and /imu/utc_ref at 1Hz.

Example config files

• ellipse_A_default.yaml, default config file for an Ellipse-A

• ellipse_E_default.yaml, default config file for an Ellipse-E with an external antenna and external Gnss

• ellipse_N_default.yaml, default config file for an Ellipse-N with an external antenna and internal Gnss

Messages publishing

SBG custom messages

The sbg_driver defines some custom ROS messages, corresponding to the SBG message protocol.

• /sbg/air_data SbgAirData

• /sbg/ekf_euler SbgEkfEuler

• /sbg/ekf_nav SbgEkfNav

• /sbg/ekf_quat SbgEkfQuat

• /sbg/ekf_event{A,B,C,D,E} SbgEvent

• /sbg/gps_hdt SbgGpsHdt

• /sbg/gps_pos SbgGpsPos

• /sbg/gps_raw SbgGpsRaw

• /sbg/gps_vel SbgGpsVel

• /sbg/imu_data SbgImuData

• /sbg/imu_short SbgImuShort

• /sbg/mag SbgMag

• /sbg/mag_calib SbgMagCalib

• /sbg/odo_vel SbgOdoVel

• /sbg/ship_motion SbgShipMotion

• /sbg/utc_time SbgUtcTime

ROS standard messages

In order to define ROS standard topics, it requires sometimes several SBG messages to be merged. You have to active the needed SBG outputs.

• /imu/data, IMU dara, requires /sbg/imu_data and /sbg/ekf_quat

• /imu/temp, IMU temperature, requires /sbg/imu_data

• /imu/velocity, IMU velocity data, requires /sbg/imu_data

• /imu/mag, IMU magnetic field, requires /sbg/mag

• /imu/pres, IMU pressure data, requires /sbg/air_data

• /imu/pos_ecef, Earth-Centered Earth_Fixed position, requires /sbg/ekf_nav

• /imu/utc_ref, UTC time reference, requires /sbg/utc_time

• /imu/nav_sat_fix, Navigation satellite, requires /sbg/gps_pos

Services

The sbg_device_mag node handles the magnetic calibration for suitable devices. It uses services to control the calibration process.

• /sbg/mag_calibration Trigger, service to start/stop the magnetic calibration

• /sbg/mag_calibration_save, Trigger, service to save the magnetic calibration.

HowTo

Configure the SBG device

For compatible devices, the SBG ROS driver allows the user to configure the device before starting the data handling.

To do so, the configuration yaml file should be modified.

# Configuration of the device with ROS.
confWithRos: true

Calibrate the magnetometers

$ roslaunch sbg_driver sbg_device_mag_calibration.launch
$ rosservice call /sbg/mag_calibration
// Proceed rotations on the IMU
$ rosservice call /sbg/mag_calibration
// If the magnetic calibration results are satisfaying, it could be uploaded
$ rosserive call /sbg/mag_calibration_save

Contributing

Bugs, issues, or features additions should be done on the Github repository.