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Settings - GPS

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 or with the close button.

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, Flarm 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 sensor 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 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 Location 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. Another possibility is to select the entry BT Adapter. In this case Cumulus will scan automatically your environment for reachable GPS Bluetooth devices. If devices have been found, a combo box dialog is opened and you can select one device from the list. Cumulus tries then to open a connection to this device. If your device selection was wrong, you have to restart Cumulus.

If your device is not contained in the selection list, you can change one of the predefined entries to your need.

Altitude Reference
The default selection is GPS. 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 from the expected value you can correct that in the altitude dialog. You can open it by tipping on the altitude display at the map view. Add your correction value in the spin box labeled with Leveling. Positive values will be added and negative values subtracted from the delivered altitude. If a GPS fix is established the correction value will be applied immediately.

Some logger devices can deliver altitude values derived from a pressure sensor. If you want to use pressure data, you have to select in the Altitude Reference combo box the entry Pressure.
Please note! If you have selected the pressure item Cumulus expects special NMEA records from the connected logger devices. Otherwise you will not get displayed any altitude and variometer data!

The following devices are supported by Cumulus:

Sync Clock
Cumulus is able to synchronize the PDA system clock to the GPS time, if the option Sync Clock is activated. But this will only work, if Cumulus is running as user root. On Nokia Internet tablet this feature is switched off because user processes are not running under the root identity.

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 and FLARM proprietary sentence with barometric or GPS altitude data.
$PFLAU FLARM proprietary sentence with status, intruder and obstacle data.
$PFLAA FLARM proprietary sentence with data about other aircraft around.
$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
$MAEMO0 Cumulus internal proprietary sentence, if LibLocation from MAEMO 5 is used.
$MAEMO1 Cumulus internal proprietary sentence, if LibLocation from MAEMO 5 is used.

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