  Red giant stars are solar-like pulsators presenting mixed-modes. Such modes
consist in a coupling between pressure waves propagating in the external
convective envelope and gravity waves propagating in the radiative interior.
Therefore, the red giant asteroseismology provides us with a direct view on
their core and opens the possibility to monitor the evolution of their core
rotation. Previous measurements of the mean core rotation revealed that angular
momentum is efficiently transferred from the core to the envelope inside red
giants, but the physical mechanisms at work are not yet fully understood. We
thus need stronger observational constraints on the evolution of the red giant
core rotation. In this context, we developed an automated method to determine
the mean core rotation of red giant branch stars observed with Kepler. This
automated method is paving the way for the future PLATO data, representing
hundreds of thousands of potential red giant oscillation spectra. Results
obtained for almost 1200 red giant branch stars indicate that the rate of the
core rotation braking is lower than previously estimated and does not seem to
depend on the stellar mass.
