Rohde & Schwarz R&S ARDRONIS-I

The R&S ARDRONIS-I from Rohde & Schwarz (Germany) is a passive RF detection and direction-finding system for the remote-control, telemetry and video links of commercial drones. A single antenna, the R&S ADD557SR, covers the range from 20 MHz to 6 GHz. The system monitors 360 degrees and can be used stationary or deployed. The manufacturer names critical infrastructure, events, police and military use as fields of use.

The receive range of 20 MHz to 6 GHz takes in the 868 and 915 MHz control and telemetry links as well as the connections at 2.4 and 5.8 GHz, and lower frequencies for unusual links. Remote ID broadcasts in the 2.4 GHz band also lie within range; whether they are evaluated depends on the software. Direction finding determines the direction from which a signal arrives; a single system gives a direction, and several systems at separate sites give a position by cross-bearing. The distance achieved depends on the drone’s transmit power, the terrain and the radio environment.

The system does not transmit and does not interfere with the drone’s radio link. Whether and how receiving and evaluating third-party radio signals is permitted (secrecy of telecommunications, data protection) has to be clarified for Germany and Poland before use. Jammers may be operated only by authorities in Germany and Poland (Section 91 TKG, Article 42 of the Polish Electronic Communications Law).

In selection the single wideband antenna counts: it simplifies the mast set-up but needs a clear view and clean alignment, since the bearing depends on it. The wide range down to 20 MHz also takes in the links of home-built drones but needs a maintained signature library so that hits are assigned correctly. Antenna cables, connectors, lightning protection and software version need checking. The system does not see drones that do not transmit, such as autonomous or fibre-optic controlled ones; that takes radar or cameras.