A test of the relativistic gravitational redhshift with Galileo satellites in eccentric orbits
Abstract
The European GNSS satellites Galileo 5 and 6 launched in August 2014 have not reached their targeted circular orbit. Instead they have been accidentally injected into an eccentric orbit, due to a failure of the Fregat upper stage. After a series of correction maneuvers their orbits now possess an eccentricity of 0.16 corresponding to a periodic variation of altitude of about 8000 km. While this is of some disadvantage for navigation purposes it offers a unique possibility to perform a precise test of the gravitational redshift as predicted by Einstein's theory of General Relativity.
Thus, with support from the European and German space agencies ESA and DLR we have conducted an analysis of the clock and orbit data from these two satellites. Both satellites are equipped with passive hydrogen maser clocks and Rubidium atomic frequency standards. The modulation that these clocks' frequencies undergo due to the gravitational redshift is approximately {Δν}/{ν} = 5 × 10^{-11}. Here we show that with the clocks onboard of these satellites a test of this general relativistic effect competitive to the most accurate such test, as obtained by the Gravity Probe A (GPA) experiment in 1976, can be achieved. We present an analysis of the available data so far covering approximately 3 years and discuss the main systematic effects we have identified. We finally give a combined statistical and systematic uncertainty and compare our result to that of GPA.- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E1446H