I think these are sightings Pauley

First produced in Sweden in 1953, the Geodimeter was based on the principle that a beam of light could be used to measure the distance from one point to another. The Geodimeter could be used to measure base lines with greater precision than previously possible and accomplish in hours what had previously taken weeks. The instrument worked by sending a light signal of known wavelength to a reflector. The wavelength of the returning signal was compared to the outgoing one, and the difference (called the "phase shift") was measured. Using multiple frequences of light, the instrument computed a distance based on the known lengths and measured phase shifts of returning light waves. The Geodimeter was the first electronic distance measurement instrument to use visible light to measure distance.