Method for checking position data of a medical instrument, and corresponding medical instrument

A method for checking the situation or position data of an instrument having at least a first section and at least a second section, wherein the first section comprises at least a first sensor and the second section comprises at least a second sensor, and wherein the method comprises the metrological determination of the situation of position, or its change, of the first sensor and the second sensor;

• the method comprising the steps of:
• determining an expression of a variable feature of the spatial reference between the situation or position of the first sensor and/or at least a spot on the first section, on the one hand, and the situation or position of the second sensor and/or at least a spot on the second section or the first section which is referenced by the second sensor on the other hand, at at least a first point in time, a second point in time, and a third point in time;
• and
• determining by a criterion whether a difference in the expression of the variable feature between a first expression at a first point in time and a second expression at a second point in time still exists at a third point in time.