Configuring Serial GPS Ports

GPS receivers are connected through a computer serial port (RS232 or USB).

To add a new GPS port, click the Add button on the Configure Ports tab. The port editing dialog will appear. Set the port type to Serial_GPS.

The other parameters you will need to specify for the GPS receiver are:

• the name of the port to which the GPS is connected. On Microsoft Windows, this will be a COM port (COM1, COM2, etc.). On Linux, this will be a /dev/ttyS port (ex. /dev/ttyS0) or a USB serial port (ex., /dev/ttyUSB0). Similar device names will be used on other Unix derivatives. Note that on Linux and Unix systems, you will need the access right to access serial ports. Typically, this will be membership in a group owning the serial ports, such as dialout, tty, or uucp. You will also need the access right to write a lock file into the lock file directory on your system. Typically, this will be membership in the lock group.

  NOTE: The Fedora Core 15 distro of Linux has a known incompatibility with the RXTX library used by YAAC to access the serial ports, due to moving the lock directory to a place not known to the RXTX library. To work around this, ensure that the /var/lock directory's group is lock and has group write privilege, and that your account is a member of the lock group as mentioned above.

• The baud rate the GPS receiver will be communicating at (typically, 4800 baud, though you may wish to configure your receiver for a higher speed). Ensure that the GPS receiver is set to the same speed as you configure this port to.
• Whether YAAC should transmit waypoint messages back to the GPS to display APRS stations and objects on the GPS screen, and, if so, which message format should be used (standard GPS waypoints, or the Kenwood proprietary message understood by the AvMap GPSs).
• Whether the GPS is local (reporting the position of the station running YAAC) or remote (reporting the position of some other object using a long serial link). The remote option is useful for situations such as amateur rocketry, where an unlicensed ISM band link is used to relay the serial GPS data from the rocket to the ground station, and the ISM receiver looks like a USB serial port to the ground station's computer. In addition, for remote GPS receivers:
  • the text name to use for displaying the remote GPS on the YAAC map.
  • the APRS symbol to use for displaying the remote GPS on the YAAC map.
  • whether or not the remote GPS should also be transmitted to the APRS networks as a locally-originated APRS Object with the specified name and symbol.

The "Test Port" button provides a means of verifying that you have connected to the correct place; it opens a terminal window connected to the configured serial port so that you can manually test the GPS receiver for the desired operation. To complete testing, close the terminal window.

Once you have the settings the way you want them, click the Save button.

You can check how well your GPS receiver is performing by selecting the menu choice View -> Show GPS Status.