The present invention relates to a method for determining the spatial position of objects, in particular medical objects, comprising the steps of: - acquiring first position data which comprise first position information describing the spatial position of an object (2) within a first co-ordinate system (A)； - acquiring first transformation data which comprise first transformation information describing a transformation of the object's position from the first co-ordinate system (A) into a second co-ordinate system (B)； - acquiring, on the basis of the first position data and the first transformation data, second position data which comprise second position information describing the spatial position of the object (2) within the second co-ordinate system (B)； - acquiring second transformation data which comprise second transformation information describing a transformation of the object's position from the second co-ordinate system (B) into an inertial co-ordinate system (I)； - determining, on the basis of the second position data and the second transformation data, inertial position data which comprise inertial position information describing the spatial position of the object (2) within the inertial co-ordinate system (I). The present invention also relates to a program which, when running on a computer (4), causes the computer (4) to perform the method steps of the method described above and/or to a program storage medium on which the program is stored and/or to a computer (4) comprising such a program storage medium and/or to a signal wave, in particular a digital signal wave, carrying information which represents the program. The present invention also relates to a tracking system for determining the spatial position of objects, in particular medical objects, comprising: - a sensor array (1 ) which is configured to determine the spatial position of at least one tracking marker attached to an object (2)； - an inertial sensor array (3) which is attached to said sen
