Method for determining a position range of a third-party drone or a transmitter of a control device of the third-party drone

The invention relates to a method and system for determining a position range (30, 32) of a third-party drone (20) or of a transmitter (44) of a control device of the third-party drone, wherein a transmission signal of the thirdparty drone or of the transmitter is detected with a first radio frequency, RF, sensor which is attached to a sensor drone (10), wherein a first solid angle range (24, 26) starting from a first detection position located on a flight path of the sensor drone (10) is determined based on the detected transmission signal, and wherein the position range (30, 32) is narrowed down (120) to the first solid angle range or is determined as the first solid angle range or as a subrange of the first solid angle range, and/or wherein the position range is determined as a function of the detected transmission signal. (Figure 1D)