A method of detecting active lighting states of radiation sources comprising the following teaching steps to be carried out at least once for a respective active lighting state of a respective radiation source: - detecting a first temporal reference progression of the intensity of radiation incident on the radiation sensor by means of a radiation sensor when the radiation source is set into the active lighting state; - detecting a second temporal reference progression of the intensity of radiation incident on the radiation sensor by means of the radiation sensor when the radiation source is set into an inactive lighting state; - determining a first reference spectrum by transforming the first reference progression into the frequency domain and determining a second reference spectrum by transforming the second reference progression into the frequency domain; - determining a difference spectrum as the difference of the first reference spectrum and the second reference spectrum; - determining a bandpass filter (43*) on the basis of the difference spectrum; - determining a first reference intensity as a mean value of the first reference progression and determining a second reference intensity as a mean value of the second reference progression; - defining a switching threshold (53*) on the basis of the first reference intensity and the second reference intensity; and the following measurement steps to be carried out, in particular continuously, for the detection of the respective active lighting state of the respective radiation source: - detecting a temporal measurement progression of the intensity of radiation incident on the radiation sensor by means of the radiation sensor; - filtering the measurement progression by means of the bandpass filter (43*); and - evaluating the filtered measurement progression on the basis of the switching threshold (53*), wherein a plurality of radiation sensors are used which differ with respect to their spectral sensitivity; wherein the respective teaching steps are carried out for each of the radiation sensors and the respective bandpass filter (43*) determined in so doing and the respective switching threshold (53*) defined in so doing are associated with the respective radiation sensor; wherein the respective measurement steps are carried out for each of the radiation sensors and the bandpass filter (43*) associated with the respective radiation sensor is in this respect used for the filtering and the switching threshold (53*) associated with the respective radiation sensor is used for the evaluation; and wherein the method, prior to the carrying out of the teaching steps and the measurement steps, further comprises: - transmitting a positioning beam oriented in a fixed spatial relationship with respect to the radiation sensor; and - placing the radiation sensor relative to the respective radiation source with respect to a reliable detection of a respective active lighting state such that the positioning beam is incident on a predefined position relative to the respective radiation source, in particular such that the positioning beam is incident on the respective radiation source. - detecting a first temporal reference progression of the intensity of radiation incident on the radiation sensor by means of a radiation sensor when the radiation source is set into the active lighting state; - detecting a second temporal reference progression of the intensity of radiation incident on the radiation sensor by means of the radiation sensor when the radiation source is set into an inactive lighting state; - determining a first reference spectrum by transforming the first reference progression into the frequency domain and determining a second reference spectrum by transforming the second reference progression into the frequency domain; - determining a difference spectrum as the difference of the first reference spectrum and the second reference spectrum; - determining a bandpass filter (43*) on the basis of the difference spectrum; - determining a first reference intensity as a mean value of the first reference progression and determining a second reference intensity as a mean value of the second reference progression; - defining a switching threshold (53*) on the basis of the first reference intensity and the second reference intensity; - detecting a temporal measurement progression of the intensity of radiation incident on the radiation sensor by means of the radiation sensor; - filtering the measurement progression by means of the bandpass filter (43*); and - evaluating the filtered measurement progression on the basis of the switching threshold (53*), - transmitting a positioning beam oriented in a fixed spatial relationship with respect to the radiation sensor; and - placing the radiation sensor relative to the respective radiation source with respect to a reliable detection of a respective active lighting state such that the positioning beam is incident on a predefined position relative to the respective radiation source, in particular such that the positioning beam is incident on the respective radiation source.