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Overview

This package provides nodes which enable bidirectional communication between socket (server) or serial devices and the nmea_msgs/Sentence message type. This may be useful for a number of scenarios, including if you:

• want your device's raw NMEA sentences to be available to other nodes, or to be bagged
• have a network-connected navsat device

• are particularly sensitive to the CPU usage incurred by PySerial

Finally, the combination of a serial_node connected directly to a socket_node can create a tee, where a device's serial data is directly available to ROS, but also served over a socket such that a remote machine may listen to it via netcat. This is particularly valuable if your device has a proprietary Windows-only GUI, which you'd like to be able to use while the device is part of a running ROS system. An example of this usage is supplied in the package, which you can launch like so:

roslaunch nmea_comms tee.launch port:=<serial port> baud:=<baud rate>

Once running, you should see the output of your serial NMEA device on the /navsat/nmea_sentence topic, as well as when running nc localhost 29500.

API

ROS nodes as detailed below. No code API.

Nodes

serial_node

Connects to a serial port, passing sentences between ROS and the port.

Subscribed Topics

nmea_sentence_out (nmea_msgs/Sentence)

• Sentences published here will be written to the serial port if a device is connected.

Published Topics

nmea_sentence (nmea_msgs/Sentence)

• Sentences received on the serial port.

Parameters

~frame_id (string, default: navsat)

• The value to use as the header's frame_id on published messages.

~port (string, default: /dev/ttyUSB0)

• Name of serial port to connect to.

~baud (int, default: 115200)

• Baud rate to connect at.

socket_node

Open a socket server, to pass NMEA sentences to and from connected clients.

Subscribed Topics

nmea_sentence_out (nmea_msgs/Sentence)

• Sentences published here will be written to connected socket clients

Published Topics

nmea_sentence (nmea_msgs/Sentence)

• Sentences received from connected clients will be published here

Parameters

~frame_id (string, default: navsat)

• The value to use as the header's frame_id on published messages.

~port (int, default: 29500)

• Port number to open socket server on.