In quest of global Radio Occultation Mission for meteorology beyond 2011

The FORMOSAT-3/COSMIC mission consisting of six satellites is the world's first demonstration of near real-time operational GPS Radio Occultation (RO) constellation mission. The success of the mission expected to operate through 2011 has initiated a new era for operational GPS RO soundings. The World Meteorological Organization had recommended continuing RO observations operationally and urges planning for a complementary follow-on mission. The follow-on mission will be a new constellation of 12 to 18 satellites equipped with the GNSS RO payload and collect over 9000 soundings per day. This higher density of sounding profiles will be useful for global and mesoscale models, and also severe weather forecasting. The follow-on mission will establish international standards so that future RO missions deployed by any country can be used together for operations and research. In this paper, we present the state-of-the-art achievements and the results of the current mission; as well as the follow-on mission planning progress.