Estimation of image centroid, size, and orientation with laser radar

Angular tracking of targets with monopulse laser radar can be performed by tracking the centroid of the image. The image irradiance distribution is sensed with an array of noncoherent photocounting detectors and the counts processed to provide estimates of the image centroid, size, and orientation. The mean and variance of the centroid and second moment are obtained for optically rough and smooth extended targets, as functions of coherence, target extent, resolution, and integration time. The limits on accuracy imposed by shot noise from the image and background irradiances and by laser speckle are discussed.