  On August 22, 2014, the satellites GSAT-0201 and GSAT-0202 of the European
GNSS Galileo were unintentionally launched into eccentric orbits. Unexpectedly,
this has become a fortunate scientific opportunity since the onboard hydrogen
masers allow for a sensitive test of the redshift predicted by the theory of
general relativity. In the present Letter we describe an analysis of
approximately three years of data from these satellites including three
different clocks. For one of these we determine the test parameter quantifying
a potential violation of the combined effects of the gravitational redshift and
the relativistic Doppler shift. The uncertainty of our result is reduced by
more than a factor 4 as compared to the values of Gravity Probe A obtained in
1976.
