A system for processing a ground at least partially in an outdoor region, in particular removing dirt or grass cuttings, includes a base station and a mobile robot unit. The system further includes at least one detection device for detecting at least one environmental variable, and a controller which influences the operating mode of the mobile robot unit in accordance with the value of at least one of the environmental variables detected by the at least one detection device. A method for controlling a mobile robot unit for processing a ground at least partially in an outdoor region, in particular removing dirt or grass cuttings, is also provided.
