In many cases, to solve applied problems, the robot needs to know its real location, which is most often different from the data stored in the on-board system. For unmanned robotic devices, as well as for ground-based robots, it is most efficient to use local navigation algorithms, which consist in determining the coordinates of the device with respect to a certain starting point. The paper discusses localization algorithms provided that the map of the area is known in advance. Particular attention is paid to the Monte Carlo localization method because of several advantages. The paper presents an example of modeling the algorithm operation.