Summary and Future Chances - GNSS Remote Sensing: Theory, Methods and Applications - page 262

12.2.3 New Missions and Systems

Space-borne GPS reflectometry and refractometry experiments have been
successful in providing estimates of a number of the Earth's surface characteristics
and atmospheric and ionospheric information, e.g., the Taiwan/US FORMOSAT-
3/COSMIC mission with six satellites. However, these missions still have some
restrictions due to low temporal-spatial resolutions and are approaching their end
of operations. In order to fully utilize these new GNSS remote sensing tools,
more and more new missions and systems are being developed. For example,
the FORMOSAT-3/COSMIC mission will reach the end of its design life in
about 2011, and the National Oceanic and Atmospheric Administration (NOAA)
and National Space Organization (NSPO) intend to launch the next generation
follow-on FORMOSAT-7/COSMIC-2 mission between 2014 and 2017 (Yen 2010 ).
This follow-on mission has a new constellation of 12 satellites with GNSS RO
receiver to receive GPS, GLONASS and GALILEO satellite signals. It will collect
a large amount of occultation point data primarily for weather forecasting including
typhoons and hurricane and space weather monitoring as well as meteorological,
climate, ionospheric, and geodetic research.
CICERO (Climate Community Initiative for Continuing Earth Radio Occulta-
tion) is a follow-on mission to the COSMIC as a self-supporting enterprise for
the greater GNSS-RO science and wider user communities who will share in its
design, evolution, and success ( www.geooptics.com ) . The CICERO project changes
the way to collect and disseminate Earth observational data with 100 micro-satellites
in Low-Earth Orbit (LEO) performing GNSS atmospheric radio occultation (GNSS-
RO) and GNSS Surface Reflection (GNSS-SR) measurements (see Fig. 12.1 ). The
CICERO constellation is designed with lower cost of acquiring data essential to
understanding our planet and expands the possibilities for obtaining new types of
data from space. The plan is to initially launch 20 satellites with follow-on launches
to reach a sustained array of 100 spacecrafts. The full CICERO constellations are
expected to deliver nearly 100,000 atmospheric profiles per a day (Yunck et al.
2007 ). Meanwhile, since CICERO has GNSS Surface Reflection (GNSS-SR), it is
expected to detect more detailed Earth's surface characteristics and time-varying
evolutions.
The past UK-DMC GPS Reflectometry experiment launched in 2003 has suc-
cessfully showed that GNSS signals can be used from space in a bi-static radar
configuration to analyze reflections off the ocean, ice and land. In order to further
test and implement GNSS-R, a new UK satellite with a GNSS-R instrument on-
board, TechDemoSat-1, is planned for launch in the near future (Unwin et al. 2010 ).
It will be designed to estimate several Earth observables, including Directional
Mean Square Slope (DMSS), ice edge detection, ice freeboard measurement, and
ionospheric delay (e.g., total electron content), in a format that allows proper
verification of inversion models by relevant scientists. The DMSS of the ocean
is an important parameter that has interest from both operational users (shipping,