COMPARATIVE PRECISION OF DISTRIBUTED-BACKSCATTER DOPPLER LIDARS

Simple formulas for the standard deviation that is available from Dopp ler velocity estimators through the use of direct-detection frequency discriminators for targets spread in range are derived and contrasted with the fundamental limits provided by the Cramer-Rao bounds for both direct-detection and heterodyne systems. The structures of these form ulas is sufficiently similar to facilitate a meaningful comparison amo ng the different systems and to provide a basis for the evaluation of experimental performance.