  In the framework of the PARIS Beta project, fundamental milestones have been
reached for the definition of future GNSS-R (Global Navigation Satellite System
signal Reflections) altimetry missions (the PARIS concept). The most important
one is the confirmation of the significant impact that GNSS-R data can have on
mesoscale oceanography, as we discuss here. In this report, we first briefly
review the contribution of satellite altimetry to mesoscale oceanography. We
then summarise recent results obtained on the mapping capabilities of existing
and future altimeter missions. From these analyses, refined requirements for
mesoscale ocean altimetry (in terms of space/time sampling and accuracy) are
derived. A review of on-going and planned altimetric missions is then performed
and we analyse how these configurations match the user requirements. Then we
will describe the simulation approach and impact analysis of GPS-R data.
