Since the early 20th century when classical meridian transits of planets can be considered sufficiently accurate many different types the positional observations including almost 400000 optic and high-precision radiotechnical measurements of planets and near- or on-the-planets spacecraft have been obtained. They made it possible not only to improve the orbital elements of planets and values related with ephemerides such as the Astronomical Unit, radius, masses and rotations of planets, but to determine some small physical parameters characterizing the fundamental properties of our physical space. The EPM2006 of IAA RAS ephemerides and, as control, DE405 of JPL ephemerides have been used to analyse the data. Unfortunately, the real accuracy of parameters is reduced by the order or more because of systematic errors of observations of an unknown origin, impossibility to completely allow for the delay in the solar corona, and large correlations between parameters; however some estimations and upper limits may be obtained.
The PPN parameters and solar oblateness produced various secular and periodic effects in orbital elements of planets have been estimated from the simultaneous solution: the quadrupole moment of the Sun J₂=(2 ± 0.5)*10^-7, |β - 1|<0.0002, |γ - 1|<0.0002. The upper limit of the density of dark matter in the Solar system resulted from the corrections to secular perihelion advance of the Earth and Mars: ρ_dim < 10^-19 g/cm³ (I.B. Khriplovich and E.V. Pitjeva, IJMPD, 2006). Estimations obtained for the unmodel secular perihelion precession of Uranus, Neptune and Pluto are substantially below 100" per century and confine the upper limit of the value of anomalous forces suggested for the acceleration of Pioneer spacecraft.