ESTIMATING PARTICLES VELOCITY FROM LASER MEASUREMENTS - MAXIMUM-LIKELIHOOD AND CRAMER-RAO BOUNDS

In this paper, we address the problem of estimating particles velocity in the vicinity of an aircraft by means off a laser Doppler system, W hen a particle passes through the region of interference fringes gener ated by two coherent laser beams, the signal backscattered is of the f orm A exp {-2 alpha(2).f(d)(2)t(2)} cos (2 pi f(d)t), where the Dopple r frequency f(d) is related to the aircraft speed, This paper is conce rned with the most precise estimation of the parameters A and f(d) in the model considered, Cramer-Rao bounds (CRB's) on the accuracy of est imates of A and f(d) are derived, and closed-formed expressions are gi ven, Approximated formulas provide quantitative insights into the infl uence of alpha and f(d). Additionally, a maximum likelihood estimator (MLE) is presented. Numerical examples illustrate the performance of t he MLE and compare it with the CRB, The influence of the SNR, the samp le size, the optical parameter alpha, and the frequency f(d) on the es timation performance is emphasized, Finally, an application to real da ta is presented.