Transportable distance measurement system for long range applications

This paper describes a transportable distance measurement system based on synthetic wavelength interferometry using two frequency-doubled Nd:YAG lasers. A non-polarizing system has been setup to eliminate polarization cross-talk issue. A partly software-implemented superheterodyne detection was performed to measure the synthetic phase. A fringe interpolation of 2π/5600 is demonstrated and an accuracy of ∼4 µm is achieved over 3 m.