An Estimator for Conical Scan Tracking Systems using Gaussian Beam Lasers

The principle of conical scan is used in laser target tracking to get information about the angle of a target illuminated by a beam with a Gaussian intensity profile [1]. Many systems use only one term in the Fourier series expansion of the target return to estimate the pointing error. That scheme can be interpreted as an approximation for the extended Kalman Filter [2] (EKF) for the Gaussian nonlinearity. Based on this observation an improved estimator is developed utilizing the information in the target return more efficiently than the current base frequency estimators.