Method for operating a steer by wire steering system for a vehicle, and steer by wire steering system

A steer-by-wire steering system for a vehicle having at least one steerable wheel, said system comprising a control device that is configured to execute the following steps:

• providing a predefined steering ratio characteristic curve (2) that defines a bijective relationship between a steering input variable (E) of a control element of the vehicle and a steering output variable (A) for displacing the steerable wheel,
• recording a first steering input value (E1) of the steering input variable (E),
• providing a magnified characteristic curve (3) that defines a bijective relationship between the steering input variable (E) and the steering output variable (A), in a magnified region (L) around the first steering input value (E1), such that a change of the steering input variable (E) starting from the first steering input value (E1), in accordance with the magnified characteristic curve (3), results in a smaller change of the associated steering output variable (A) in comparison with the predefined steering ratio characteristic curve (2),
• forming a modified steering ratio characteristic curve (4) on the basis of the predefined steering ratio characteristic curve (2), wherein the predefined steering ratio characteristic curve (2), in the magnified region (L) around the first steering input value (E1), is replaced by the magnified characteristic curve (3),
• recording a second steering input value (E2) of the steering input variable (E), and
• determining a steering output value (A2) in order to drive the steerable wheel on the basis of the second steering input value (E1) and the modified steering ratio characteristic curve (4).