LASSO Observations at McDonald (Texas, USA) and OCA/CERGA (Grasse, France). A Preliminary Analysis

The LASSO observations between USA and Europe have been made possible with the move of Meteosat 3/P2 toward 50 deg W. Two Lunar Laser Ranging stations participated into the observations : the MLRS at McDonald Observatory (Texas, USA) and OCA/CERGA (Grasse, France). Common sessions were performed since April 30, 1992, and will be continued up to the next Meteosat 3/P2 move further West (planed for January 1993). The preliminary analysis made with the data already collected by the end of November 1992 shows that the precision which can be obtained from LASSO is better than 100 ps, the accuracy depending on how well the stations maintain their time metrology, as well as on the quality of the calibration (still to be made.) For extracting such a precision from the data, the processing has been drastically changed compared to the initial LASSO data analysis. It takes into account all the measurements made, timings on board and echoes at each station. This complete use of the data increased dramatically the confidence into the synchronization results. See also ADA267301. Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (24th) Held in McLean, VA on 1-3 Dec 1992.