Overview of
the Tracking and Control Center
at the Tsukuba Space Center
Table of Contents
Page
1. Outline of the Tsukuba Space Center
2. Role of the Tsukuba Tracking and Control Center
3. Tracking and Control Network
4. Types of Tracking and Control Data
5. Operations for the Advanced Land Observing Satellite
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3
5
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1. Outline of the Tsukuba Space Center
JAXA’s Tsukuba Space Center (TKSC), located in Tsukuba Science City, sits on a 530,000 square-meter site
with beautiful natural surroundings. It is a central facility for JAXA with various testing and operation
facilities. The TKSC plays an important role including research on and the development of spacecraft, such
as satellites and rockets, tracking and controlling launched satellites, development of the Japanese
Experiment Module (JEM) "KIBO" as part of the International Space Station project, and astronaut training.
2. Role of the Tsukuba Tracking and Control Center
The Tsukuba Tracking and Control Center plays a pivotal role for smoothly and systematically carrying out
tracking and control operations of satellites that have been launched in Japan. The center has the following
three functions.
a. Network Control
Many satellites are moving in their respective orbits over the earth, thus it is idealistic that we can
freely communicate with a satellite by a radio frequency whenever we want to monitor its status
or send a command. Therefore, it is better to have as many ground radio frequency stations
(tracking and communication stations) in various places as possible so that we can access a
satellite anytime and more flexibly. JAXA performs tracking and control operations of satellites
by using both Japanese and overseas ground stations.
The Tsukuba Tracking and Control Center is in charge of determining responsibility sharing and
the setting up of data transmission lines among ground tracking and communication stations for
satellites, as well as managing the operations by systematically putting stations and information
together (Figure-1 and 2.)
For the Advanced Land Observing Satellite (ALOS), the space network that consists of the Data
Relay Test Satellite (DRTS), and Tsukuba and Hatoyama Feeder Link Stations will be mainly
used.
b. Satellite Control
Status information on satellite onboard equipment is sent from the satellites as “status signals
(telemetry)” to the Center via tracking and communication stations in Japan or overseas or data
relay satellites. At the Center, telemetry is processed in real time (or semi-real time), satellite
conditions are monitored, operation plans for each piece of onboard equipment are drawn up, and
commands are sent for controlling satellites.
c. Flight Dynamics
At the Center, orbits for satellites are determined based on tracking data acquired by each ground
station. Orbit estimation that is necessary for tracking a satellite by the space network and
ground stations is also carried out. An orbit control plan that is a prerequisite for maintaining a
satellite within its scheduled orbit range is compiled based on the calculated satellite orbit, then
actual control results are evaluated.
For cartography, one of the ALOS’s major objectives, it is necessary to determine the precise
measurement of the position of the satellite when it takes high-resolution images.
By processing data from the ALOS onboard dual-frequency GPS receiver at the Center, satellite
positioning will be determined with accuracy to a meter.
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2
TLM/RNG
TLM/RNG
TLM/RNG
TLM/RNG
Figure-1:
TLM/RNG
ANT-PRD
CMD
OPLAN
軌道情報
ALOS Tracking and Control System
ＳＬＲ：Satellite Laser Ranging
ＡＮＴ－ＰＲＤ：Antenna Prediction
TLM/RNG
Operation Request
CMD
Tsukuba Primary
Ground Terminal
(PGT)/ Hatoyama
Ground Terminal
(HGT) (Feeder link
stations)
MISSION DATA：Mission Equipment data
ＯＰＬＡＮ：Operation Plan
ＲＥＱ:
←MISSION DATA
←Receiving request
Receiving Plan→
Overseas
Stations
MISSION-DATA)
(TLM,RNG,
Ka-BAND
Ka-BAND(CMD,RNG)
ＤＲＴＳ
Earth
Observation
Center (EOC)
REQ/ low mission data（TLM、GUTS）
Tracking and Control Bldg. Tsukuba
Space Center （ＴＡＣＣ）
ＲＮＧ：Ranging Data
ＴＬＭ：Telemetry
ＣＭＤ：Command
TLM/RNG
TLM/RNG
ANT-PRD
ANT-PRD
ANT-PRD
ANT-PRD
ANT-PRD
ANT-PRD
CMD
CMD
CMD
CMD
CMD
CMD
Mobile St.
（ＯＫＮ１）
Mobile St.
（ＭＳＤ１）
Mobile St.
（ＫＴＵ１）
Mobile St.
（ＰＲＴ１）
Mobile St.
（ＳＮＴ１）
Mobile St.
（ＭＳＰ１）
Mobile St.
（ＫＲＮ１）
Okinawa 1st
Katsuura 1st
Masuda 1st
X-BAND(MISSION-DATA)
KSA(MISSION-DATA)
SSA(TLM,RNG)
X-BAND(MISSION-DATA)
SSA(CMD,RNG)
Kiruna 1st
Santiago 1st
Perth 1st
USB(CMD,RNG)
Maspalomas 1st
＊1)
Supported by the International Laser
Ranging Service (ILRS) in Japan and overseas
Masuda
SLR＊１
USB(TLM,RNG)
Laser Ranging
ＡＬＯＳ
The photo below is of a tracking and control room where all kinds of information and data from ground
stations as well as launch vehicle flight data from the launch site are gathered in real time when a satellite is
launched. The room plays the role of a control tower for satellite tracking and control as the data and
information are displayed without delay so that operators understand the situation immediately to issue
necessary instructions and commands swiftly and accurately.
Tsukuba Tracking and Control Center
3. Tracking and Control Network
For the network control function, JAXA normally uses three Japanese tracking and communication stations
(in Masuda, Katsuura, and Okinawa), and four overseas stations (in Kiruna, Santiago, Perth, and
Maspalomas.)
For the ALOS, the space network is scheduled to be mainly used from the initial verification phase after
completion of the function verification with the data relay satellite system. Mission data acquisition in the
regular operational phase will be carried out at the Hatoyama Feeder Link Station via the Data Relay Test
Satellite (DRTS or “Kodama.”)
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JAXA facilities
EOC
36°00’ Ｎ
139°21’ Ｅ
TKSC
36°04’ Ｎ
140°08’ Ｅ
Katsuura St.
35°12’ Ｎ
TKSC: Tsukuba Space Center
TNSC: Tanegashima Space
Center
EOC: Earth Observation Center
Katsuura St.: Katsuura Tracking
and Communication Station
Masuda St.: Masuda Tracking and
Communication Station
Okinawa St: Okinawa Tracking
and Communication Station
140°18’ Ｅ
Masuda St.
TNSC
30°23’ Ｎ
131°01’ Ｅ
30°33’ Ｎ
131°01’ Ｅ
Okinawa St.
26°30’ Ｎ
127°54’ Ｅ
SNT1(Santiago)
33°09’Ｓ
70°40’Ｗ
MSP1(Maspalomas)
27°46’ Ｎ
15°38’ Ｗ
KRN1(Kiruna)
67°53’ Ｎ
21°04’ Ｅ
PRT1(Perth)
31°48’Ｓ
115°53’Ｅ
Figure-2:
Map of Launch / Tracking and Control Facilities
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4. Types of Tracking and Control Data
a. House Keeping Data
House keeping data shows the health conditions of a satellite including battery voltage, power
generation of a solar battery, electric current condition, temperature of each piece of equipment,
and attitude. Data is acquired by decoding and understanding telemetry data sent from a satellite.
b. Command Data
Command data is instructions to a satellite such as to turn on or off onboard equipment and to use
a gas jet to control its orbit or attitude.
c. Tracking Data
Tracking data is precise position information measured at a tracking and communication station at
a certain time including the distance to a satellite, range rate, elevation angle, and azimuth.
Based on these pieces of information, the position of an on-orbit satellite is calculated by the flight
dynamics system, and its position is estimated for a certain time.
5. Operations for the Advanced Land Observing Satellite
At the Center, tracking and control are being performed using the network shown in Figure-1 and 2 for
smooth satellite operations by acquiring telemetry data, sending command data, determining orbits and
making orbit estimation.
For the ALOS, JAXA plans to carry out tracking and control and mission data acquisition using the space
network as part of the inter-orbit communication experiment.
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Japan Aerospace Exploration Agency
“Overview of the Tracking and Control Center at the Tsukuba Space Center”
Second Edition, December 2005