Laser tracker with a warm air flow shield for the measurement beam

A coordinate measuring machine for determining the position of a target embodied as a retroreflector or at least having a retroreflector, the coordinate measuring machine comprising:

• a base defining a vertical axis;
• a beam guiding unit for emitting measurement radiation from a measurement radiation emergence aperture and for receiving at least some of the measurement radiation reflected at the target;
• wherein
• the beam guiding unit is swivelable about the vertical axis and an inclination axis relative to the base, and
• a measurement axis is defined by an emission direction of the measurement radiation;
• a distance measurement unit for measuring the distance to the target by means of the measurement radiation;
• an angle measurement functionality for determining an alignment of the beam guiding unit relative to the base;
• a target acquisition unit for determining an impact point of radiation reflected by the retroreflector on a sensor of the target acquisition unit and for producing an output signal for controlling a fine targeting functionality;
• and
• a heat influence reduction component which is embodied and arranged on the coordinate measuring machine in such a way that, as a result thereof,
• heat emission influencing the near region free beam path of the emitted measurement radiation situated in the near region of the coordinate measuring machine and caused by heating of internal components of the coordinate measuring machine, and/or
• warm air, which is produced by such heat emission, is obstructed or prevented from passing through the near region free beam path during the heat-induced rise thereof.