A plurality of autonomous mobile robots includes a first mobile robot and a second mobile robot. The first mobile robot is provided with a transmitting optical sensor for outputting laser light, and a first module for transmitting and receiving an Ultra-Wideband (UWB) signal. The second mobile robot is provided with a receiving optical sensor for receiving the laser light and a plurality of second modules for transmitting and receiving the UWB signal. A control unit of the second mobile robot determines a relative position of the first mobile robot based on the received UWB signal and a determination of whether the laser light is received by the optical sensor.