A method for adapting a threshold value of a detection device comprising the following steps: Transmission of a signal burst having a predefined pulse-repetition interval, a predefined burst length and a defined signal frequency; receiving and processing of a receive signal, in particular by means of amplification, filtering and demodulation, so as to obtain the envelope; determining a receive-signal magnitude as interference-level sample from the receive signal following a first predefined time duration (Δt1) starting with a signal burst within a predefined second time duration (Δt2), preferably at the end of the pulse repetition interval; and adapting the threshold value of the detection device as a function of the interference level sample. Also provided is a device for adapting a threshold value of a detection device.