Driver MT3339

Overview

This package includes driver software for the [MT3339] GPS Receiver. THis is the chip used in the Adafruit Ultimate GPS module.

Keywords: mt3339 gps driver

License

The source code is released under a MIT license.

Author: Paul D'Angio (forked from their repo)

The driver_mt3339 package has been tested under [ROS] Melodic and Ubuntu 18.04. This is research code, expect that it changes often and any fitness for a particular purpose is disclaimed.

Installation

Building from Source

Dependencies

• Robot Operating System (ROS) (middleware for robotics)
• serial (ROS serial package)
• sensor_msgs_ext (ROS extended sensor messages)

Building

To build from source, clone the latest version from this repository into your catkin workspace and compile the package using

    cd catkin_workspace/src
    git clone https://github.com/REZOOM-UMD/ros-driver_mt3339.git driver_mt3339
    cd ../
    catkin_make

Usage

Run the driver with the following command:

    rosrun driver_mt3339 driver_mt3339

Nodes

node

A driver for interacting with the [MT3339] GPS. Enables configuration and reading of NMEA data.

Published Topics

• /gps_mt3339/fix (sensor_msgs_ext/gnss_fix)

    The status of the sensor's GNSS fix.
  

• /gps_mt3339/position (Commented out) (sensor_msgs_ext/gnss_position)

    The current GNSS position. Only published while a fix is available.
  

• /gps_mt3339/position/covariance (Commented out)

    The covarainces for GPS pose estimate.
  

• /gps_mt3339/track (sensor_msgs_ext/gnss_track)

    The current GNSS track. Only published while a fix is available.
  

• /gps_mt3339/time (sensor_msgs_ext/time_reference)

    The current UTC time measured by the sensor. Only published while a fix is available.
  

• Added: /gps_mt3339/navsat_fix (Commented out) (sensor_msgs/NavSatFix)

    The GPS lat, long, altitude along with covariances, ROS time stamped with frame_id: "base_link" (can be changed).
  

Parameters

• ~/serial_port (string, default: /dev/ttyUSB0)

    The serial port connected to the sensor. This is automatically detected if launched using gps_mt3339_launcher.py in the main scooter code package.
  

• ~/baud_rate (uint32, default: 38400)

    The baud rate to use for serial communication with the sensor.
  

• ~/connection_settle_time (uint32, default: 300)

    The number of milliseconds to wait after opening the serial port and test connectivity to the sensor.
  

• ~/timeout (uint32, default: 300)

    The number of milliseconds to wait for message responses from the sensor.
  

• ~/update_rate (uint32, default: 100)

    Changes the position update rate of the MT3339 GPS in milliseconds.
    The acceptable rates are between 100ms and 10,000ms.
    Position fixes are output once every period specified, so 100ms = 10Hz.
  

• ~/frame_id (string, default: base_link)

    The name of the coordinate frame that the sensor is located in.
  

• ~/uere (double, default: 6.74)

    The User Equivalent Range Error (UERE) representing the total pseudorange error budget.  This is typically 6.74 for C/A, and 6.0 for P(Y).