Abstract: An arrangement for measuring speeds between a first and a second object with the aid of microwave signals and including a microwave generator which is connected to a transmitter antenna, and two receiver antennae which are preferably placed on respective sides of the transmitter antenna for receiving microwave signals reflected against an object and each of which receiver antennae is connected to a respective receiver channel, the channels being connected to a correlator for correlating the signals received by the receiver antennae, the mutual time difference of said signals corresponding to the relative speed between the objects. According to the invention the microwave generator (11) is also connected to a respective mixer (13, 14, 15, 16) in each of the receiver channels, to which respective mixers (13-16) respective receiver antennae (6, 7) are connected.