The Influence of Elliptical Gaussian Laser Beam on Inversion of Terrain Information for Satellite Laser Altimeter

Abstract The transmitted laser mode of Geosciences Laser Altimeter System (GLAS) is a significant factor in determining the received pulse waveforms, which are used for inversing target information. The inversion algorithms in the scientific literature are based on the assumption that the transmitted laser is circular Gaussian. The practical laser pattern of GLAS is not circularly symmetric, but elliptical Gaussian. The received pulse shape will contain a bias, which would cause an error in the inversion information. In this paper, we describe new theoretical models about received pulse signal and inversion errors of range, surface slope and roughness. We present the results of waveforms shape and inversion errors for three representative terrains with different surface slope and roughness. The results show that the maximal inversion errors of range, surface slope, and roughness will reach 24.25 cm, 8.82° and 4.58 m, respectively, which cannot be negligible. Therefore, the inversion information should be reevaluated and amended depending on the type of terrain.