Multi-beam laser heterodyne measurement with ultra-precision for the angle based on oscillating mirror sinusoidal modulation

This paper proposes a novel method of multi-beam laser heterodyne measurement for the angle. Based on Doppler effect and heterodyne technology, loaded the information of the angle to the frequency difference of the multi-beam laser heterodyne signal by sinusoidal frequency modulation of the oscillating mirror, which move as simple harmonic motion, this method can obtain many values of the angle after the multi-beam laser heterodyne signal demodulation simultaneously. Processing these values by weighted-average, it can obtain the angle accurately. This novel method is used to simulate measurement for incident angle of standard plane mirror by MATLAB, the obtained result shows that the relative measurement error of this method is just 0.49%.