Andrew Yee
March 9th 06, 03:41 PM
ESA News
http://www.esa.int
9 March 2006
GIOVE A transmits loud and clear
After a successful launch on 28 December 2005, GIOVE A began transmitting
navigation signals on 12 January 2006. Work is currently being performed
to check the quality of these signals.
In space, the success of a mission relies on the achievement of a series
of milestones. This is especially true for a pioneering mission such as
GIOVE A, the first Galileo satellite, launched late last year under the
European Space Agency's responsibility.
Manufacture, launch, reaching final orbit and transmission of first
signals: all these key steps were met by the satellite, which is now going
to achieve its first goal, the filing for the frequencies allocated to
Galileo by the International Telecommunication Union (ITU).
After launch and platform commissioning, GIOVE A started signal
transmission on 12 January and the quality of these signals is now being
checked. This checking process is employing several facilities, including
the Navigation Laboratory at ESA's European Space Research and Technology
Centre (ESTEC), in the Netherlands, the ESA ground station at Redu, in
Belgium, and the Rutherford Appleton Laboratory (RAL) Chilbolton
Observatory in the United Kingdom.
Chilbolton's 25 metre antenna makes it possible to acquire the signals
from GIOVE A and verify they conform to the Galileo system's design
specification. Each time the satellite is visible from Chilbolton, the
large antenna is activated and tracks the satellite. GIOVE A orbits at an
altitude of 23 260 kilometres, making a complete journey around the Earth
in 14 hours and 22 minutes.
Every orbital pass provides an opportunity to analyse the signals from the
satellite. The quality of the signals transmitted by GIOVE A will have an
important influence on the accuracy of the positioning information that
will be provided by the user receivers on the ground, so a detailed
check-out of the signal properties is mandatory. The signal quality can be
affected by the environment of the satellite in its orbit and by the
propagation path of the signals travelling from space to ground.
Additionally, the satellite signals must not create interference with
services operating in adjacent frequency bands, and this is also being
checked.
The engineers at Chilbolton have means to observe and record in real time
the spectrum of the signals transmitted by GIOVE A. Several measurements
are performed relating to transmitted signal power, centre frequency and
bandwidth, as well as the format of the navigation messages generated
on-board. This allows the analysis of the satellite transmissions in the
three frequency bands which are reserved for it and confirmation that
GIOVE A is transmitting that which is expected of it.
The GIOVE A mission also represents an opportunity for the testing of a
key element of the future Galileo system, the user receivers. The first
Galileo experimental receivers, manufactured by Septentrio of Belgium,
were installed at the Redu and Chilbolton In Orbit Test Stations and at
the Guildford, United Kingdom, premises of Surrey Satellite Technology
Limited (SSTL), the manufacturer of the satellite and now in charge of its
control in orbit.
A meticulous task, sometimes tedious, but essential for the progress of
the project, ensuring that Galileo, the joint civilian navigation
initiative from the European Space Agency and the European Commission, can
offer the value added services which will fundamentally depend on the
quality of the transmitted signals.
Related news
* First Galileo signals transmitted by GIOVE-A
http://www.esa.int/esaCP/SEMQ36MZCIE_index_0.html
* First Galileo satellite on orbit to demonstrate key technologies
http://www.esa.int/esaCP/SEMSRO8A9HE_index_0.html
Related links
* Galileo Joint Undertaking (GJU)
http://www.GalileoJU.com
* Galileo website (European Commission)
http://europa.eu.int/comm/dgs/energy_transport/galileo/index_en.htm
* ITU -- satellite regulatory procedures
http://www.itu.int/newsarchive/wrc2000/presskit/how-sat.html
* RAL Chilbolton Observatory
http://www.chilbolton.rl.ac.uk/
* Chilbolton and GIOVE A
http://www.chilbolton.rl.ac.uk/esa_galileo.htm
* Surrey Satellite Technology -- GIOVE A
http://www.sstl.co.uk/index.php?loc=111
* Septentrio (receiver development)
http://www.septentrio.com/
IMAGE CAPTIONS:
[image 1:
http://www.esa.int/esaCP/SEM21VMVGJE_index_1.html]
The 25 metre antenna at the Chilbolton Observatory of the Rutherford
Appleton Laboratory
Credits: ESA / RAL
[Image 2:
http://www.esa.int/esaCP/SEM21VMVGJE_index_1.html#subhead1]
The 25 metre antenna at the Chilbolton Observatory of the Rutherford
Appleton Laboratory, seen from the control room.
Credits: ESA / RAL
[Image 3:
http://www.esa.int/esaCP/SEM21VMVGJE_index_1.html#subhead2]
First spectrum obtained from GIOVE A
Credits: ESA / RAL
http://www.esa.int
9 March 2006
GIOVE A transmits loud and clear
After a successful launch on 28 December 2005, GIOVE A began transmitting
navigation signals on 12 January 2006. Work is currently being performed
to check the quality of these signals.
In space, the success of a mission relies on the achievement of a series
of milestones. This is especially true for a pioneering mission such as
GIOVE A, the first Galileo satellite, launched late last year under the
European Space Agency's responsibility.
Manufacture, launch, reaching final orbit and transmission of first
signals: all these key steps were met by the satellite, which is now going
to achieve its first goal, the filing for the frequencies allocated to
Galileo by the International Telecommunication Union (ITU).
After launch and platform commissioning, GIOVE A started signal
transmission on 12 January and the quality of these signals is now being
checked. This checking process is employing several facilities, including
the Navigation Laboratory at ESA's European Space Research and Technology
Centre (ESTEC), in the Netherlands, the ESA ground station at Redu, in
Belgium, and the Rutherford Appleton Laboratory (RAL) Chilbolton
Observatory in the United Kingdom.
Chilbolton's 25 metre antenna makes it possible to acquire the signals
from GIOVE A and verify they conform to the Galileo system's design
specification. Each time the satellite is visible from Chilbolton, the
large antenna is activated and tracks the satellite. GIOVE A orbits at an
altitude of 23 260 kilometres, making a complete journey around the Earth
in 14 hours and 22 minutes.
Every orbital pass provides an opportunity to analyse the signals from the
satellite. The quality of the signals transmitted by GIOVE A will have an
important influence on the accuracy of the positioning information that
will be provided by the user receivers on the ground, so a detailed
check-out of the signal properties is mandatory. The signal quality can be
affected by the environment of the satellite in its orbit and by the
propagation path of the signals travelling from space to ground.
Additionally, the satellite signals must not create interference with
services operating in adjacent frequency bands, and this is also being
checked.
The engineers at Chilbolton have means to observe and record in real time
the spectrum of the signals transmitted by GIOVE A. Several measurements
are performed relating to transmitted signal power, centre frequency and
bandwidth, as well as the format of the navigation messages generated
on-board. This allows the analysis of the satellite transmissions in the
three frequency bands which are reserved for it and confirmation that
GIOVE A is transmitting that which is expected of it.
The GIOVE A mission also represents an opportunity for the testing of a
key element of the future Galileo system, the user receivers. The first
Galileo experimental receivers, manufactured by Septentrio of Belgium,
were installed at the Redu and Chilbolton In Orbit Test Stations and at
the Guildford, United Kingdom, premises of Surrey Satellite Technology
Limited (SSTL), the manufacturer of the satellite and now in charge of its
control in orbit.
A meticulous task, sometimes tedious, but essential for the progress of
the project, ensuring that Galileo, the joint civilian navigation
initiative from the European Space Agency and the European Commission, can
offer the value added services which will fundamentally depend on the
quality of the transmitted signals.
Related news
* First Galileo signals transmitted by GIOVE-A
http://www.esa.int/esaCP/SEMQ36MZCIE_index_0.html
* First Galileo satellite on orbit to demonstrate key technologies
http://www.esa.int/esaCP/SEMSRO8A9HE_index_0.html
Related links
* Galileo Joint Undertaking (GJU)
http://www.GalileoJU.com
* Galileo website (European Commission)
http://europa.eu.int/comm/dgs/energy_transport/galileo/index_en.htm
* ITU -- satellite regulatory procedures
http://www.itu.int/newsarchive/wrc2000/presskit/how-sat.html
* RAL Chilbolton Observatory
http://www.chilbolton.rl.ac.uk/
* Chilbolton and GIOVE A
http://www.chilbolton.rl.ac.uk/esa_galileo.htm
* Surrey Satellite Technology -- GIOVE A
http://www.sstl.co.uk/index.php?loc=111
* Septentrio (receiver development)
http://www.septentrio.com/
IMAGE CAPTIONS:
[image 1:
http://www.esa.int/esaCP/SEM21VMVGJE_index_1.html]
The 25 metre antenna at the Chilbolton Observatory of the Rutherford
Appleton Laboratory
Credits: ESA / RAL
[Image 2:
http://www.esa.int/esaCP/SEM21VMVGJE_index_1.html#subhead1]
The 25 metre antenna at the Chilbolton Observatory of the Rutherford
Appleton Laboratory, seen from the control room.
Credits: ESA / RAL
[Image 3:
http://www.esa.int/esaCP/SEM21VMVGJE_index_1.html#subhead2]
First spectrum obtained from GIOVE A
Credits: ESA / RAL