A position-measuring device for determining the positions of two objects
movable with respect to each other along a measuring direction includes a
first radiation source for emitting an electromagnetic beam of rays, a
beam splitter, which splits each beam of rays emitted by the radiation
source into at least one first and one second partial beam of rays, a
reference reflector arranged in the beam path of the first partial beam
of rays, a measuring reflector, movable with respect to the reference
reflector along the measuring direction, which is arranged in the beam
path of the second partial beam of rays, a device for superposing the two
partial rays of beams after their reflecting at the respective reflector,
for generating a measuring signal, a second radiation source for emitting
additional electromagnetic beams of rays and a combining device for
combining the additional electromagnetic beams of rays into the beam path
of the electromagnetic beam of rays generated by the first radiation
source. In the position-measuring device, a detection device is arranged
such that it receives a reference signal formed by superposition of the
beams of rays emitted by the first radiation source and the additional
beams of rays, and an evaluation device is assigned to the detection
device, which is equipped and provided for evaluating the reference
signal formed by the superposition of the beams of rays of the two
radiation sources for generating a reference pulse.