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Three payload instruments are on-board the FORMOSAT-1
satellite: the Ocean Color Imager (OCI), the Ionosphere
Plasma and Electrodynamics Instrument (IPEI), and
the Experimental Communication Payload (ECP). Three
science teams consisted of faculties and researchers
from major national universities in Taiwan have
taken the lead to analyze the FORMOSAT-1 experimental
data.
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 Ocean Color Imager (OCI) |
Up to September 2001, the OCI science team at National
Taiwan Ocean University has processed more than
7000 OCI images, which have been utilized for oceanography
studies by institutions around the world. More than
twenty organizations in Taiwan have applied for
OCI image data. In addition, the OCI 865nm channel
data have been analyzed by the science team to deduce
the aerosol optical depth, a measure of the number
of particles in the air, during the dust storm season
from March to May in China. The OCI science team
has used the OCI data to publish numerous articles
about atmospheric correction algorithms, the OCI
radiometric characterization, and features of ocean
color and aerosol optical depth around Taiwan.
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▲ An OCI ocean color
image of sea water in the Taiwan neighborhood.
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- False color plots of aerosol optical depth
deduced from the OCI data displays a large region
of dust storm particles in yellow sea on January
29, 2001 and February 14, 2001.
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| Ionosphere
Plasma and Electrodynamics Instrument (IPEI) |
The IPEI science team at National Central University
has been examining the FORMOSAT-1 observations of
equatorial anomaly and plasma bubbles over Taiwan
and its equatorial neighborhood. The science team
also used the IPEI measurements to study mid-latitude
ionospheric density irregularities during magnetic
disturbances. The coincident observations of large
ion depletion events by FORMOSAT-1 and DMSP satellites
together with Millstone Hill ISR ground radar have
been analyzed to investigate space weather effects
during major magnetic storms. Amazingly, the IPEI
instrument has detected an "ionospheric density
hole" above Brazil during the Bastille Day
Event, the biggest magnetic storm event happened
on July 14, 2000. During this event, an extensive
two-dimensional profile of ionospheric density hole
has been measured in situ for the first time by
a satellite. To further take advantage of the IPEI
measurements, the IPEI science team has collaborated
with the MU Radar of Japan, ISR of Peru and U.S.
Air force Geophysical Laboratory to perform radio
beacon and ionospheric experiments.
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- FORMOSAT-1 satellite contains the Ionosphere
Plasma and Electrodynamics Instrument (IPEI)
payload as shown here during integration and
test. The IPEI payload is made of an ion trap
instrument to measure ion density, two ion drift
meters to measure ion drift velocities in the
cross-track directions, and a retarding potential
analyzer to infer ionospheric plasma parameters
of major ion constituents.
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- The IPEI payload on board FORMOSAT-1 measures
the effects of plasma bubbles in the ionosphere,
which affect communications between satellites
and ground antennas.
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- FORMOSAT-1 satellite has measured large ion
density holes during July 15-16, 2000, when
the biggest magnetic storm event in the last
decade, known as the Bastille Day event, occurred.
The IPEI data from six FORMOSAT-1 orbits were
composed to display the 3-D structures of the
ionospheric density holes in the region of weaker
Earth magnetic fields above Brazil known as
South Atlantic Anomaly.
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| Experimental Communication Payload (ECP) |
Three Ka-band communication experiments using the
FORMOSAT-1 Experimental Communication Payload (ECP)
have been conducted. The first experiment conducted
by the science team of National Tsing Hua University
was direct broadcasting digital television signals
via FORMOSAT-1. The science team of National Cheng
Kung University has employed the transportable and
fixed ground terminals to transmit video/audio signal
to ECP for direct broadcast experiments, and to
receive 19.5 GHz beacon signal from ECP for propagation
experiments. Finally the science team of National
Central University has conducted an experiment to
measure the propagation of Ka-band signals and their
rain attenuation effects in Taiwan. The main objective
is to investigate satellite-signal characteristics
at Ka-band over Taiwan area. This experiment would
determine various attenuation effects of Ka-band
propagation due to rain particles, clouds, water
vapor content, melting hydrometers, and atmospheric
refractivity fluctuations.
The FORMOSAT-1 ECP ground system has two ground
stations: a remote ground terminal at National Cheng
Kung University at Tainan, and a transportable ground
terminal. The remote ground terminal can transmit
and receive Ka-band signals to carry out ECP experiments,
whereas the transportable ground terminal could
only receive Ka-band signals from FORMOSAT-1. The
transportable ground terminal has two vehicles:
one equipped with antenna and the other with the
control equipment.
In addition to the two ground stations, NSPO operates
a science data distribution center. Its main functions
are to schedule satellite experiments, to transmit
orbit information to the remote ground station at
National Cheng Kung University, and to archive experimental
results.
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- FORMOSAT-1 contains the Experimental
Communication Payload (ECP) to conduct
three Ka-band communication experiments.
Microelectronic Technology Inc. (MTI)
used the technology from NEC Corp to fabricate
the space segment of the ECP payload.
The payload has an uplink frequency of
28.25 GHz, a downlink frequency of 18.45
GHZ, and a beacon frequency of 18.45 GHz.
The frequency bandwidth is 27 MHz. The
transmitter power is 10 watts in the communication
channel. The antenna coverage is conic
with a 6.5 degree cone angle. The transmitter
antenna has a 25.4 cm diameter, whereas
the receiver antenna has a 20.3 cm diameter.
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- An operator uses ECP to conduct experiments
for transmitting video/audio signals to
the ground receiver terminals. The right
terminal screen shows the video of an
operator in conversation with another
operator at the ground receiving station.
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