Error analysis of reference-beam laser Doppler velocimeter

Basic principles of reference-beam laser Doppler velocimeter (LDV) is expounded. The influences of error factors on LDV measurements are theoretically analyzed, such as principle formula approximation, Gauss-beam interference, laser linewidth, detector aperture, finite transition time, signal processing algorithm, change of air refractive index and angle measurement. The theoretical formula of measurement error caused by each error factor is presented, and the influence of optical parameters on each error is discussed. Theoretical analyses and experiments show that, narrow-band laser and small-aperture photoelectric detector are required to reduce measurement errors in experiments. When one chooses beam facular aperture and the angle of between light central beam and particle motion direct