Algorithm of ensemble pulsar time

An algorithm of the ensemble pulsar time based on the Wiener filtration method has been constructed. This algorithm has allowed the separation of the contributions of an atomic clock and a pulsar itself to the post-fit pulsar timing residuals. The method has been applied to the timing data of the millisecond pulsars PSR B1855+09 and PSR B1937+21 and allowed to filter out the atomic scale component from the pulsar phase variations. Direct comparison of the terrestrial time TT(BIPM96) and the ensemble pulsar time PTens has displayed that the difference TT(BIPM96) - PTens is within +/- 0.4 mu s range. A new limit of gravitational wave background based on the difference TT(BIPM96) - PTens was established to be Omega(g)h(2) similar to 10(-10).