Absolute distance meter based on a frequency-modulated laser diode

This article describes a distance measuring instrument based on a frequency-modulation continuouswave interferometer implemented in a compact setup suitable for industrial applications. Theprototype uses a visible laser diode that is frequency-modulated with a triangular wave form.Measurements carried out with a cooperative target show a measuring range from 130 to 300 mmwith a relative accuracy of 1200 ppm