Abstract

Satellite laser ranging is widely exploited, in geodesy and geophysics. The goal expected tobe reached by the Nineties is to obtain one millimeter accuracy to determine tire range of satellite up to 7000 kilometers. Using the existing technology based on the single photon detection technique, the satellite range is measured routinely¹ with 7 millimeters single shot precision. Depending on the amount of data and the nature of the measurements involved, the measured ranges may be compressed forming so-called normal points obeying higher precision. Two dominant factors that limit the accuracy have to be considered: the satellite retroreflector array geometry contribution and the lack of an appropriate atmospheric dispersion model. One of the possibilities to improve the atmospheric dispersion model is to determine the differential time of the pulse propagation at different wavelengths within a few picoseconds depending on the selected wavelength pairs.² Picosecond ranging offers a chance to reach tire goal. However, the state of the art of laser and detector and atmospheric transparency technology gives a limited choice of wavelength pairs to be used. The Nd:YAG- based lasers offer combinations of the fundamental, second, and third harmonics. Using the Raman shift of the second harmonic in hydrogen, we obtained the first Stokes radiation at 0.68 micrometers and the first anti-Stokes at 0.45 micrometers.

© 1993 Optical Society of America