Determining distances by time-of-flight measurement of laser light is the method of choice in the range from centimeters to several hundred meters when high accuracy and measurement rate have to be achieved even under difficult and changing environmental conditions. To measure distances, light is emitted towards and reflected by the object. Using the speed of light and the measured time-delay of the light from the light source (emitter) to the object and back to the detector as the basis, it is possible to calculate the distance between laser emitter and target object. Laser diodes are generally employed as light sources. High-resolution scanner systems with high measuring rates call for finely focused, high-quality measuring beams. Fast and sensitive avalanche photodiodes (APD) provide the detectors. We employ both pulse time-of-flight and phase shift measurement methods.