A method according to one embodiment of the invention relates to
determining at least one parameter of a model that provides information
about a position of an object. The object may include a plurality of
alignment marks of which desired positions are known. The method includes
measuring a plurality of positional parameters for each alignment mark.
Based on the measured plurality of positional parameters, which are
weighted with weighing coefficients, at least one parameter of the model
of the object is determined. The numerical value of each weighing
coefficient is determined together with the at least one parameter of the
model.