Double sideband frequency scanning interferometry for distance measurement in the outdoor environment

Frequency scanning interferometry (FSI) can achieve high-precision absolute distance measurement. Here, a new double sideband frequency scanning interferometry (DSB-FSI) system is proposed, which enables long-range, high-precision measurements. Furthermore, a new fringe counting method based on all-phase FFT (apFFT) is used, which can accurately estimate the number of fringes under the condition of blinking intensity of the echo and can effectively suppress the phase estimation error caused by spectrum leakage. In outdoor experiments, the target is placed at about 880 m from the system. The standard deviation of distance measurement is 16.59 μm at the condition of stationary and 17.45 μm at the condition of vibration neglecting the influence of air refractive index Ultimately, it has been verified that DSB-FSI enables absolute high-precision measurement of long-range in outdoors.