| 摘要 |
The present invention relates to method for presence control in a vehicle (1), using at least a first and second arrangement (3, 4) for transmitting and receiving microwave radiation, the method comprising the following steps for each one of said arrangements (3, 4): actuating a microwave transmitter (13) detecting microwave radiation with a microwave receiver (15); and determining a possible presence in the vehicle (1). The method furthermore comprises: each one of said arrangements transmitting using a certain actuation frequency, different from the other; each microwave receiver (15) detecting both the reflected signals from its own microwave transmitter (13) and the transmitted energy from the other microwave transmitters (13) in said arrangements (3, 4), such that mixing products occur as well as difference frequencies of the mixing products, constituting interference; and adapting the actuation frequencies such that, for each one of said arrangements, said interference appear outside the pass band of a Doppler band pass filter. |
