Effect of speckle pattern on laser Doppler velocimeters by varying angle between the laser beam direction and the velocity

摘要

This paper presents a theoretical analysis speckle effect and a comparison with experiment results on laser Doppler velocimeters at different velocity. We have found that the value of ratio between broadening of frequency and center frequency is about 30% from 32.2mm/s to 379.6mm/s and effect of speckle pattern is one of the prime reasons .The error caused by effect of speckle pattern is an intolerant value in velocity measurements.