SYSTEM HAVING A PLURALITY OF SCANNING UNITS OF A POSITION-MEASURING DEVICE

摘要

The present invention relates to a system for measuring the position of an object relative to a reference system. In this regard, the object is arranged to be movable along at least two orthogonal first and second main movement axes relative to the reference system. In order to measure the position of the object relative to the reference system, the position measuring device comprises at least two two-dimensional measurement criteria arranged along the first main movement axis and four scanning units for optical scanning of these measurement criteria. In addition, at least four additional extended scanning units are provided along the first main movement axis between the four scanning units.