ADS-B; A GUIDE TO CONNECTING GPS-DEVICES, ADS-B RECEIVERS, MODE-S TRANSPONDERS AND DISPLAYS...page 6

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GPS-SOURCES

GPS is a system that is able to calculate the position of the unit based on the reception of satellite signals. The position as calculated by the unit can be made available for other devices through output ports in various formats. A common standard used is the NMEA...NMEA 0183 to be precise. Detailed information about NMEA can be found on this website. The most important NMEA-sentence for ADS-B OUT purposes is the GPRMC-sentence which contains the position information as well as velocity, track, date and time. To assure maximum quality of the ADS-B OUT data it is essential to remove all other NMEA-sentences from the data-string generated by the GPS-source. In many cases this can be configured in the GPS-source, in other cases an external filter or converter is required. Below you will find a few examples of GPS-sources widely used in gliders and the procedures to confgure them for correct data-output for ADS-B OUT.

FlarmFlarmMouse

A majority of gliders is equipped with some sort of Flarm-device (Flarm Original, PowerFlarm, LXNAV FlarmMouse, LX Navigation RedBox and MiniBox or a Flarm OEM-module integrated in a navigation computer (e.g. LXNAV LX80X0- and LX90X0-series) or in an ADS-B receiver (e.g. TRX-1500 and TRX-2000)). A standalone Flarm-device houses a GPS-receiver and a low-power, license-free ISM band radio transceiver for transmitting and receiving position data. The GPS-data generated by the Flarm can also be used as a source for position data for ADS-B OUT purposes. The challenge however is to remove all Flarm-data from the data-string produced by the unit. Various solutions for this are available: GPS-filters, TRX ADS-B receivers (e.g. TRX-1090 and TRX-2000) or filters integrated in the electronics of the connected transponder. Basic Flarm-devices have limited output-ports which usually means that the use of a signal splitter is also required.

PowerFlarm Core (Pure)PowerFlarm Core (Pure)

The PowerFlarm Core (Pure) belongs to the latest generation of standalone Flarm-devices and houses two configurable output-ports. See Chapter Receiving data...ADS-B IN for all details concerning the connection and configuration of the PowerFlarm Core (Pure). With only two output-ports it usually is necessary to use a signal splitter here as well.

LXNAV LX80X0- & LX90X0-series

The LX80X0- and LX90X0-navigation computers are very advanced and highly configurable devices capable of providing position data to external devices such as transponders. For this the most obvious method is to use the PC-port on the cable-bundle of the unit (round 5-pin Binder). The data being transmitted via this port can be configured under Setup>Hardware>NMEA (pic 16). Select Ext.(PC) as port and the baudrate as specified for the connected transponder. Keep the GPS-data as raw as possible by selecting GPRMC only.LX80X0- & LX90X0-series

LX8000
pic 16

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