ISRO to launch navigation satellite on March 28

Chennai: India's fourth navigation satellite
will be launched on March 28 evening, the
Indian space agency said on Monday.
According to Indian Space Research
Organisation (ISRO), the Indian rocket -
Polar Satellite Launch Vehicle (PSLV-XL) -
will blast off with the fourth satellite of the
Indian Regional Navigation Satellite System
(IRNSS) at 5.19 p.m. on March 28.
The 1,425 kg satellite is called IRNSS-1D
and will be the first satellite to be put into
orbit by an Indian rocket in 2015.
"The rocket has been moved to the launch
pad or the umbilical tower. The rocket will
be fixed to the umbilical tower," MYS
Prasad, director of the Satish Dhawan Space
Centre, told IANS over phone from
Sriharikota.
India's only rocket port is located at
Sriharikota in Andhra Pradesh around 80 km
from Chennai.
According to Prasad, after the rocket is
connected to the umbilical tower system,
checks would be carried out including full
rocket and satellite checks.
Originally ISRO had planned to launch the
IRNSS-1D satellite on March 9.

   service to
users across the country and the region,
extending up to an area of 1,500 km.
Though the full system comprises nine
satellites - seven in orbit and two on the
ground as stand-by - the navigation services
could be made operational with four
satellites, ISRO officials had said.
Each satellite costs around Rs 150 crore and
the PSLV-XL version rocket costs around
Rs.130 crore. The seven rockets would
involve an outlay of around Rs 910 crore.
The entire IRNSS constellation of seven
satellites is planned to be completed this
year itself.
The first satellite IRNSS-1A was launched in
July 2013, the second IRNSS-1B in April
2014 and the third on October 16, 2014.
Once the regional navigation system is in
place, India need not be dependent on other
platforms.
Meanwhile European space agency
Arianespace is also getting ready to launch
two Galileo satellites on March 27.

  

The two satellites would be launched jointly
by a Soyuz rocket blasting off from French
Guyana.
According to Arianespace, the Galileo
programme is Europe's initiative for satellite
navigation. Providing a highly accurate
global positioning system under civilian
control, it would consist of 30 satellites in
total, along with European control centres
and a worldwide network of sensor and
uplink stations.
For more about satellites click here

How satellite works...
HOW SATELLITE NAVIGATION WORKS
Navigation beacons must be as visible as
possible. So 20th century radio navigation
towers guiding aircraft stood hundreds of
metres tall, while the lighthouses guarding
mariners of treacherous waters reach dozens
of metres in height or cling to high ground. In
essence navigation satellites are the same,
except they are built on the ultimate high
ground of space, making them visible from
anywhere on Earth.
Turning time into distance
The signal emitted from each satellite is a
microwave radio wave containing the time it
was transmitted and the satellite’s current
orbital position.
As signals travel at the speed of light then (if
your time-keeping is accurate enough) by
calculating the time difference between the
satellite signal and your receiver, you can
derive the precise distance the signal has
travelled from the satellite to reach your
receiver.
Ultra-precise satellite navigation relies on the
same basic principle as counting the seconds
after a lightning flash before the
accompanying thunder is heard, in order to
estimate a storm’s remoteness: a time value
is converted into a reckoning of distance.
Finding your place
....