Method of determining the position of a landmark in the environment map of a self-propelled unit, the distance of the landmark from the unit being determined dynamically by the latter

A method of determining a position of a landmark in an environment map of a self-propelled unit, a distance of the landmark from the unit being determined dynamically by the unit, comprising the steps of:

• a) determining, at least by the unit, a position change using at least one first measuring device arranged on the unit;
• b) determining, by the unit, at least one distance of a first obstacle in the environment relative to the unit using at least one second measuring device arranged on the unit, and entering the first obstacle in the environment map as a first landmark;
• c) corresponding, at least at a starting position of the unit, the position of the unit and the location of the first landmark in the environment map to real relationships in the environment;
• d) determining, after a movement of the unit away from the starting position, at least one first position of the unit relative to the starting position with a position uncertainty;
• e) determining, from the first position of the unit, at least one first distance to the first obstacle with a location uncertainty and measuring a first distance to a suspected second obstacle, a determining landmark;
• f) measuring, from a second position of the unit, at least one second distance to the suspected second obstacle;
• g) calculating, for the second position of the unit, using the first distance to the first obstacle and a position change between the first position of the unit and the second position of the unit, a predicted second distance to the first obstacle and to the suspected second obstacle;
• h) determining, as a system error, at least a difference between the measured second distance to the suspected second obstacle and the calculated predicted second distance to the suspected second obstacle;
• and
• i) allocating, for determining the position of the first landmark, the position of the first landmark to the position of the suspected second obstacle in the environment map if a magnitude of the system error falls below a fixed value and is positive.