OGN-Tracker Frequently Asked Questions

Principle of operation

OGN-Tracker provides visibility on the OGN network: it transmits signal containing time, position, altitude, ground speed, ground track, vertical speed, ground turning rate and GPS DOP.
It can as well transmit device status like battery level, temperature, pressure, and basic information about the aircraft like the registration, aircraft type, pilot name, base airfield, etc.

The OGN-Tracker transmits its signal on the 868MHz ISM band. The exact transmittion frequencies are 868.2 and 868.4MHz. The modulation used is GFSK 50kbps, Manchester encoding, +/-50kHz deviation, the occupied bandwidth is about 250kHz and the packets are 5ms long.

What signal the OGN-Tracker transmits ?


The essential parts are:

  • CPU
  • GPS reciever
  • RF transmitter/receiver


The first implemention used STM32 CPU, it has been ported to ESP32. In principle any CPU of this or similar type can be used as long as it provides access to SPI port to control the RF chip, serial port to read the GPS and I2C to read the pressure sensor

RF chip

The first implementation of the OGN-Tracker used SPIRIT1 RF, later implementations used RFM69 modules as these became easily available and then RFM95 which provided LoRa functionality.
In principle most generic FSK capable RF chips can be used to produce the OGN-Tracker signal.

GPS receiver

Any NMEA capable GPS receiver can be used.

MAVlink port of a drone

In place of the GPS reciever MAVlink port of an drone can be used to provide position and other information to the OGN-Tracker to transmit.


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