The invention regards a method for generating a representation of a working area of an autonomous lawn mower and a system including an autonomous lawn mower with at least one movement sensor, a base station and a boundary wire forming a closed loop and being connected with the base station. The autonomous lawn mower and the base station are capable to interact with each other such that the autonomous lawn mower can determine whether it is in its home position. The home position is a predetermined position that is always taken when the mower returns to the base station, for example for charging or pausing. The autonomous lawn mower further comprises a memory, for storing measured values from its at least one movement sensor. In its processor, a trajectory is generated based on the measured values, wherein the processor is further configured to calculate a total error between the position and orientation according to the calculated trajectory and the home position after reaching the home position again. This to
