Patent ID: 8922395

Claim:
A method for detecting a wheel of a vehicle by emitting an electromagnetic measuring beam having a known frequency progression over time from a detector unit, recording frequencies of the measuring beam that is reflected to the detector unit over time relative to the known frequency progression over time as a received signal, and detecting a change of a predetermined kind in the received signal as a wheel, wherein the vehicle comprises an onboard unit, which can establish a radio communication with a transceiver of the detector unit and stores information that indicates the vehicle length at least indirectly, comprising: reading said information from the onboard unit by way of a radio communication and measuring the speed of the vehicle; computing the duration of passage of the vehicle passing the detector unit based on this information and the speed; determining a time window in the received signal which shows an approximately constant change of the received signal over the aforementioned duration; determining a spurious signal component in a segment of the received signal that immediately precedes the time window; and compensating the received signal in the time window by the spurious signal component before the aforementioned detection of the wheel is carried out.