Geoscience Reference
In-Depth Information
VLBI Space Observatory Program
This is a space VLBI project held by the Institute of Space and Astronautical
Science (ISAS) under the Japanese Ministry of Education, Science and Culture. It
emits via an antenna of 8 m equivalent aperture to the Earth satellite orbit, forming a
space VLBI station with an apogee of over 20,000 km. Most of the ground VLBI
stations in the world have been involved in the space-ground VLBI observation of
this project which has therefore become a global VLBI collaborative project.
VLBI Deep Space Exploration and China's VLBI Network
In recent years, as mankind's need for deep space exploration grows, there has
appeared more concern over the role and significance of using VLBI to track and
position man-made satellites and space objects. Europe and other countries like the
USA and Japan have gradually established their own space VLBI networks and
constantly update them. They have obtained satisfactory results in application by
the VLBI network's tracking of space objects. The USA has successfully applied
VLBI techniques to many space exploration projects (e.g., Apollo 16, Pioneer,
Voyager, Galileo, etc.) due to its dominant position in space and its mature
development regarding the application of VLBI techniques in space exploration.
Its positioning accuracy has also been improved from 10 milliarcseconds at the
beginning to better than 1 milliarcsecond in the 1990s. Japan's planned lunar
exploration project (SELENE Project) will also adopt the VLBI technique and it
has already carried out the relevant applied research.
China's VLBI began to develop in the late 1970s. In 1979, a proposal was
officially raised on the establishment of China's VLBI and VLBI station system,
including Shanghai station, Urumqi station, and Kunming station, and one relevant
processing center. A 25-m radio antenna was also authorized to be built in Shang-
hai. The Sheshan station in Shanghai was completed and underwent test operation
in November 1987. In April 1988, it began to carry out many international VLBI
connection projects in astro-geodynamics, for instance, Sino-Japan collaborative
observation, Sino-German cooperation program in VLBI geodesy, VLBI observa-
tions of the American (NASA) CDP (Crustal Dynamics Project), DOSE (Dynamics
of Solid Earth), CORE (Continuous Observations of the Rotation of the Earth)
programs, and APSG (Asia-Pacific Space Geodynamics) VLBI observations.
In October 1994, the Nanshan station in Urumqi was completed, allowing
China's VLBI technique to be further developed. By the end of 1998, a VLBI
mobile station with a 3-m aperture antenna, mainly set in Kunming, Yunnan, was
put into test operation. The same year, the Shanghai Sheshan VLBI station was
involved in the differential VLBI observations for positioning of the Mars Global
Surveyor organized by NASA and yielded great results. In 1999, both the Sheshan
and the Nanshan stations became the base stations of the CORE program. In 2003,
these two VLBI stations succeeded in tracking and observing the launch process of
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