Assessment method for navigation systems

Assessment method with the following steps, a) navigating a vehicle (10) using a primary navigation system (12) b) simultaneously determining the position of the vehicle (10) using a secondary navigation system (14), wherein the primary navigation system (12) at least temporarily a higher accuracy than the secondary navigation system (14) c) determining an error in the (by the secondary navigation system 14) determined position of the vehicle (10) determined on the basis of (through the primary navigation system 12) position of the vehicle (10).