In the weak signal regime coherent Doppler lidar velocity estimates ar
e characterized by a localized distribution around the true mean veloc
ity and a uniform distribution of random outliers over the velocity se
arch space. The performance of velocity estimators is defined by the s
tandard deviation of the good estimates around the true mean velocity
and the fraction of random outliers. The quality of velocity estimates
is improved with pulse accumulation. The performance of velocity esti
mates from two different coherent Doppler lidars in the weak signal re
gime is compared with the predictions of computer simulations for puls
e accumulation from 1 to 100 pulses. (C) 1997 Optical Society of Ameri
ca.