Synthesis fraction method for multiwavelength interference absolute distance measurement

Absolute distance measurement is increasingly in demand in applications such as large-scale equipment manufacturing and satellite formation flying. Multi-wavelength interferometry is an effective method for achieving high-precision, large-range absolute distance measurement. Excess fraction method is the basic approach to solve the distance in multi- wavelength interferometry, but this method requires a large number of comparisons of fractional phases to obtain the integer phase of each wavelength, so thousands of calculations are required. The proposed solution in this paper involves directly determining the fractional fringe of the synthetic wavelength using the fractional fringe of each individual wavelength, establishing the integer fringe for each wavelength and the final distance measurement result.