A new radar mapping technology designed to generate high-
resolution, three-dimensional maps of Earth beneath foliage
and other vegetation has been licensed by NASA’s Jet
Propulsion Laboratory in Pasadena, Calif., to EarthData
International, Inc., Fresno, Calif.

This will be the first system that will be able to map above,
through and below the vegetation canopy, providing important
information such as data about landslides that are overgrown with

The National Imagery and Mapping Agency (NIMA), in conjunction
with JPL and EarthData International, Inc., showcased the
Geographic Synthetic Aperture Radar (GeoSAR) mapping system to
an audience of congressional sponsors and potential military and
civilian users of GeoSAR map products during an open house held
at the Signature Aviation Hangar, Ronald Reagan National Airport,
Washington, D.C., on Friday, June 8.

“A special feature of the GeoSAR system will be its ability to
acquire three-dimensional images of Earth’s surface through a
technique called interferometry,” said Dr. Scott Hensley, the
system developer at JPL. “Because GeoSAR uses radar, the system
will be able to operate both day and night, under almost any
weather condition.”

JPL designed and constructed the radar systems and the
processing software, which was licensed to EarthData
International, Inc., a mapping and remote sensing company, from
the California Institute of Technology in Pasadena, which manages
JPL for NASA. After the system is fully tested, EarthData plans
to use this license to provide GeoSAR mapping services on a
commercial basis to both military and civilian clients.

Building on JPL’s years of leadership and experience in the
field of interferometric radar remote sensing, the GeoSAR team
concluded that the most promising way to measure Earth beneath
the trees is to use a combination of X-band and P-band (UHF)
radar waves. The shorter wavelength X-band radar measures near
the tops of the trees, while the longer wavelength P-band (UHF)
radar penetrates the foliage. Using data from the dual-frequency
radar, the GeoSAR system can produce high-resolution elevation
models with precise vertical accuracies to 1 to 5 meters (3 to 16

The GeoSAR system can allow the military to rapidly map vast
areas where limited data exist from other sources. Other
federal, state and local government agencies as well as private
sector organizations also may use GeoSAR data to better
understand seismic change in forested areas, assess forest fire
damage or measure timber volumes and biomass. The data will also
help in land use planning, environmental protection, flood plain
management and other geographic analyses.

The program, which is managed by NIMA, will undergo a
yearlong test period. During this test period, using
EarthData’s Gulfstream-II aircraft, JPL and EarthData, with
NIMA support, will collect GeoSAR imagery and data over sites
in California, the Eastern United States, the Northwest,
Alaska and South America. These data collections will enable
JPL to refine the data processing algorithms. NIMA
anticipates the system will be commercially operational by
late 2002.

The Defense and Civil Programs Office at JPL is responsible
for the collaboration between JPL and EarthData. The
collaboration is just one of several JPL programs designed to
bring the benefits of the space program to American industry.
JPL is the lead U.S. center for robotic exploration of the
solar system.

More information about the GeoSAR system is available
online at