RSS-based RFID transponder distance estimation for fawn saving

The present publication addresses the RFID transponder distance estimation based on received signal strength (RSS) in the application of fawn saving. During the pasture mowing fawns shall be protected from mowing machines by a RFID transponder localization system. At the moment the localization system is set on direction-of-arrival only. To facilitate the search process the localization capabilities shall be extended by a distance estimation. Two RSS measurement methods are shown and evaluated. The developed measurement hardware and the RFID system are presented. Measurement results in an outdoor environment, with a RFID transponder equipped with a ceramic chip antenna, are shown. Theoretical link budget of the RFID system is derived and can be approved by the measurement results.