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GPS Daemon

gpsd is a service daemon that monitors one or more GPSes or AIS receivers attached to a host computer through serial or USB ports, making all data on the location/course/velocity of the sensors available to be queried on TCP port 2947 of the host computer, see gpsd for more information.

Get the Address of the GPS Device

  • Before plugging the GPS device into the USB socket, enter: 

    ls /dev

  • It will return a list of all the connected devices. Plug the GPS device into the USB, you can check that the device is connected by using the command: 

    lsusb

  • It shows all the connected devices, the Stemedu GPD device shows as U-Blox AG. 

    $ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 1546:01a7 U-Blox AG [u-blox 7]
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

  • Running the first command again and the GPS device will now be listed. The Stemedu USB GPS module is typically listed at /dev/ttyACMO.

Configure the GPS Device Service Daemon Connection

Before starting the GPS Device Service, a GPS daemon must be running. The device service can connect to a daemon running on either the same host or a different host.

Linux comes with a daemon called gpsd that can process the information delivered by a GPS device. To install gpsd use the command:

sudo apt-get install gpsd

To start the GPS daemon locally, complete the following steps:

  1. First, stop the GPS daemon to ensure that it is not already running or connected to an unintended device using the following commands:

    sudo systemctl stop gpsd
sudo systemctl stop gpsd.socket

  2. Check that the GPS daemon port is not in use, using the following command, replacing <gpsd_port> with the port number of your GPS daemon. The default port number is usually 2947.

    netstat -aon | grep <gpsd_port>

    The result is empty if the port is not in use.

  3. Ensure the GPS daemon has privileges to attach to the device using the following command. Replace </dev/tty> with the address of your GPS device on the host.

    sudo chmod 777 </dev/tty>

  4. Start the GPS daemon, using the following command. Replace </dev/tty> with the address of your GPS device on the host. 

    gpsd -N -n -G </dev/tty> -D1

  5. Check that the GPS daemon port is now in use using the following command, replacing <gpsd_port> with the port number of your GPS daemon. 

    netstat -aon | grep <gpsd_port>