Recently Galileo satellites started to provide correct ephemeris information for all 4 launched satellites (in spite of the fact that they are still marked unhealthy).
So we were able to compute position based on only Galileo satellites and on combined GPS+Glonass+Galileo constellation.
Below there are some graphs, collected in Moscow region:

Combined GPS+Glonass+Galileo RTK-fixed solution (zero baseline).
Used signals are L1 (E1) , L2 and L5 (E5A).

• Computed altitude
• Number of used satellites
• List of tracked satellites

Galileo-only E1 stand-alone solution. In spite of the fact that PDOP was rather high at the beginning, position remains stable. Probably this is due to the good accuracy of transmitting ephemeris.

• Computed altitude
• Dilution of precision