Project Title:
GPS Enabled Spread Spectrum Altimeter (GESSA)
94-1 08.02 8798
GPS Enabled Spread Spectrum Altimeter (GESSA)
Abstract:
An innovative approach to satellite ocean altimetry is proposed
that combines modern advances in navigation and communications. By
combining the Global Positioning System (GPS), for real time orbit
determination, spread spectrum precision ranging and solid state
microwave phased array antenna methods. a system is formed called
the GPS Enabled Spread Spectrum Altimeter (GESSA). Using the
precision orbit information on-board the satellite, the spread
spectrum ranging system can be optimally controlled. The
electronically steered phased array antenna allows for variable
altimeter swath widths. In addition to providing 2 cm accuracy
altimetry. the spread spectrum ranging enables a single frequency
approach to ionospheric calibration that eliminates the need for a
second frequency radar on board the satellite which traditional
incurred significant cost penalties. The GESSA approach is well
suited to small spacecraft missions while matching or exceeding the
state-of-the-art in spaceborne ocean altimetry and at a
considerable savings.
On a world-wide basis, there are now many maturing satellite
companies that are specializing in very small satellite missions
which will be customized to specific client needs. GESSA will have
application for the maritime industry. by exploiting ocean
altimetry capability in open ocean topographic measurement from
which circulation anomalies of fronts and eddies can be located.
Such oceanic topographic information is very useful in the fishing
industry and to offshore platform operations. In addition, the
altimetry sensitivity to sea state and sea ice offers an important
space business opportunity for the real time measurement of sea
roughness and navigation hazards information development with a fee
based dissemination service to maritime users. The attractiveness
of such space business opportunities depends critically upon
demonstrated GESSA accuracy and affordability of the relevant space
instrument system. Once the GESSA system is actually demonstrated,
there will be a great demand for such instruments, and their
oceanographic data products will enjoy a global market demand.
Key Words
International Series Research, Inc.
4225 26th St., Suite A.
Boulder, CO 80304
(303) 447-8798