ANALYSIS OF LLR DATA BY THE PROGRAM SYSTEM ERA

Aleshkina E.Yu., Krasinsky G.A., Vasilyev M.V.

Institute of Applied Astronomy of the Russian Academy of Sciences, Zhdanov st.,8, 197042 St.Petersburg, RUSSIA
e-mail: mvv@ipa.rssi.ru, fax: (812) 230-74-13

Some results of analysis of lunar ranging data from 1969 are presented. A relevant dynamic theory has been constructed by numerical integration of the equations of motion of the major planets, Moon and lunar librations by a method which is similar to that used in the DE200 ephemerides. To make the integrated equations be completely selfconsistent an optional approach with the simultaneous integration of the Earth's precession and nutation was tested. For computing partial derivatives with respect to estimated parameters the variation equations have been simultaneously integrated for lunar and solar coordinates and velocities as well as for libration angles and their velocities. The equations include also the variations of a number of other estimated parameters (lunar libration coefficients, lower harmonics of the lunar gravitational potential, lunar tidal deceleration). During the integration process the variables and their partials have been saved in the form of Chebyshev polynomials to be readily used while computing residuals and partials.

Some preliminary results of estimating the large set of the parameters involved in lunar ranging data are presented and compared with the estimates published.

Constructing the dynamic theory and processing the lunar ranging data is realized as a special application in the frame of the more general computing system ERA developed for processing of various types of high-precision observations.