Speckle effects on statistical performance of optical radar

The statistical performance of optical radar using energy detection techniq ues has been studied in this paper. The analytical expressions of the speck le number subtended by the receiving aperture are derived. The results show that the speckle number is only determined by the relative size of the spe ckle cell and the area of the entrance pupil. The receiving aperture will i ntegrate a considerable number of speckle cells when the beam expander is n ot adopted in the transmitting optical system. Few speckle cells will be in tercepted by the aperture when the beam expander is employed and the laser speckle is expected to be the dominant noise source. The detection performa nce of airborne and space-based optical radar has been analyzed based on tw o critical parameters-the speckle number and the average photoelectron coun ts. The probability density function of photoelectrons and the detection pr obability are derived for a number of occasions.