  At present the Radioastron (RA) Earth's satellite having very elliptic orbit
is used for probing of the gravitational red shift effect [1, 2]. Objective of
this test consists in the enhancing accuracy of measurement to check the
correspondence of value of the effect to Einsten's theory at one order of value
better then in was done in the GP-A experiment [3]. There are two H-masers in
disposal, one at the board of satellite and other at the Land Tracking Station
(LTS). One can compare its mutual time rate using communication radio links
between RA and LTS. In contrast with the GP-A experiment there is a possibility
of measurement repetition and accumulation of data in the process of RA orbital
circulation. In principle it might be resulted in the increasing of the
integral accuracy. In this paper we investigate the achievable accuracy in the
frame of particular method of the red shift extraction associated with the
techical specific of RA mission.
