1. A method of determining a position of a probe that has been inserted into a body of a subject, comprising the steps of: providing a processing unit and a probe model; determining an apparent position of said probe in said body with the processing unit; using the processing unit and the probe model to establish that a first displacement between said apparent position and a prior position of said probe at a known time corresponds to a first rate of motion that exceeds a predetermined limit; using the processing unit to adjust said apparent position to a new position such that a second displacement between said new position and said prior position corresponds to a second rate of motion that is less than said predetermined limit; and displaying said new position.