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### Settings

GPS

Here you can enter connection information regarding your GPS receiver. Select the correct device and baud rate for your GPS if necessary. Please refer to your GPS manual for these values.

Cumulus can provide you some status information concerning your GPS reception. If you want to know what satellites are in view, where they are, how strong their signal is, or if you want to take a look at the raw NMEA stream of your GPS, use the G key or click on the GPS status indicator in the status bar. This will open a status dialog for the GPS. The dialog can be closed with the Escape key.

Note that Cumulus will only accept GPS data sentences with a valid checksum. It is also able to process the proprietary sentences emitted by a Cambridge, Volkslogger or LX device and to process this these data. Wind, variometer and MacCready data from such devices will be taken over automatically, if they are available. MSL and STD altitude, derived from the pressure sonde are only taken on demand.

GPS Device
  In the combo box you can select the device to be used for your GPS connection. There are the following devices available:

  - Serial devices (RS232) like /dev/ttyS0.
  - Bluetooth devices like /dev/rfcomm0
  - USB devices like /dev/ttyUSB0
  - GPS Daemon
  - NMEA Simulator
  Serial and Bluetooth devices need also a speed rate for their operation. The default serial NMEA connection speed is 4800 bps for Bluetooth we recommend to use 115200 bps.

  If you use a Nokia Internet Tablet N800/N810/N900 the entry GPS Daemon should be your first selection unless you want to connect via your USB interface adapter to the GPS. In such a case select the device /dev/ttyUSB0.

  If your device is not contained in the selection list, you can change one of the predefined entries to your need. This is unsupported on the Nokia Internet Tablet.
Altitude Reference
  Most of the GPS devices send MSL (mean sea level) altitudes but some send HAE (Height above ellipsoid.) If your displayed altitude deviate always by a constant factor, try the other setting for your GPS. If that will not help, you can select the Altitude User mode and add an own altitude correction in the spin box below.

  - If you use a Cambrigde device as GPS source, it delivers also altitude values (MSL and STD) derived from a pressure sonde. Shall Cumulus work on this base, select the Pressure item in the combo box.
  - If you use a Volkslogger device as GPS source, it can deliver altitude derived from a pressure sonde. These values are related to STD. To get the right MSL altitude, you have to setup the QNH value in the Preflight Settings. Shall Cumulus work on this base, select the Pressure item in the combo box and enable the sending of the PGCS record in the Volkslogger setup menu.
  - If you use a LX device as GPS source, it delivers also altitude values derived from a pressure sonde. Shall Cumulus work on this base, select the Pressure item in the combo box and enable the sending of the LXWP records in the LX setup menu. On a LX20 device you have to enter the Password menu. Enter the password, default is 96990 and goto the NMEA menu. In the NEMA menu set the entry LXWP? to 'Y'. Set the transfer speed in Cumulus to 4800 bps. The LX20 device uses this speed for NEMA transfer regardless of the selected PC transfer speed.
  Please note! If you have selected the pressure item in the combo box Cumulus expects the special NMEA records from the connected logger devices. Otherwise you will not get displayed any altitude and variometer data!
Special Options
  Some GPS devices can be initialized by saved position data to find a satellite signal more quickly. To enable this check Soft start. If this does not work, a Hard start can be forced when Cumulus starts up. If there are still problems to get the device working, a Reset to factory settings can be initiated by pressing the button.
Update system clock
  Cumulus is able to synchronize the PDA system clock to the GPS time, if the option Update system clock is activated. But this will only work, if Cumulus is running as user root. On Nokia Internet tablet this feature is switched off.

Processed GPS sentences

Cumulus processes the following NMEA and proprietary sentences:

$GPRMC | Recommended Minimum Specific GNSS Data
$GPGLL | Geographic Position - Latitude and Longitude
$GPGGA | Global Positioning System Fixed Data
$GPGSA | GNSS DOP and Active Satellites
$GPGSV | GNSS Satellites in View
$GPDTM | Map datum
$PGRMZ | Garmin proprietary sentence with altitude information
$PCAID | Cambridge proprietary sentence with STD altitude
!w | Cambridge proprietary sentence with MSL altitude, QHN setting, wind direction, MacCready, wind speed and variometer
$PGCS | Volkslogger proprietary sentence with STD altitude
$LXWP0 | LX Navigation proprietary sentence with MSL altitude, variometer and wind data
$LXWP2 | LX Navigation proprietary sentence with McCready data

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