Abstract: Laser spot centroid locating is the key of ground-based calibration of spaceborne laser altimeter’s pointing angle. Definition of the ground spot centroid is introduced based on far-field distribution of laser spot. The flexibility, advantages and disadvantages of Gauss surface fitting algorithm, intensity centroid localization algorithm and square weighted centroid localization algorithm are analyzed from the aspects of positioning accuracy, anti-interference ability, calculation. The modeling and centroid calculation of ground-based spot are carried out, and the application characteristics of each centroid localization algorithm are analyzed and compared. Results show that the laser spot locating by the three algorithms are consistent, and the square weighted centroid localization algorithm is most suitable for the field calibration data processing.

Key words: laser techniques, centroid location；ground-based calibration, laser spot, Gaussian distribution, fitting