a method and system for alignment of sensor units comprised in at least two independent communication devices operating in the same environment , the method may comprise the steps of receiving a first signal representing sensor data collected by a first sensor unit comprised in a first communication device , receiving a second signal representing sensor data collected by a second sensor unit comprised in a second communication device , calculating a correlation function between the first signal and the second signal , defining the time difference between first and second signals by finding a maximum in the correlation function while time shifting the first and the second signals and calibrate the first and second sensor units to compensate for the defined time difference .