crpf samachar may_ june-2012 - Central Reserve Police Force

Global Positioning System (GPS)
The Global Positioning System (GPS) is a
space-based satellite navigation system
that provides location and time information in all
weather, anywhere on or near the Earth, where there
is an unobstructed line of sight to GPS satellites. It is
maintained by the United
States government and is
freely accessible by anyone
with a GPS receiver.
The GPS project was
developed in 1973 to
overcome the limitations
of previous navigation
systems, integrating ideas
from several predecessors,
including a number of
classified engineering
design studies from the
1960s. GPS was created and realized by the U.S.
Department of Defence (DoD) and was originally
run with 24 satellites. It became fully operational
in 1994.
Applications
While originally a military project, GPS is
considered a dual-use technology, meaning it has
significant military and civilian applications.
GPS has become a widely deployed and useful
tool for commerce, scientific uses, tracking,
and surveillance. GPS's accurate time facilitates
everyday activities such as banking, mobile phone
operations, and even the control of power grids by
allowing well synchronized hand-off switching.
Basic functions of GPS
� To know Position and coordinates.
� The distance and direction between any two
waypoints, or a position and a waypoint.
� Travel progress reports.
� Accurate time measurement.
ebZ&twu 2012
Technical Feature
Ajay Dwivedi,
Dy. Commandant,
CIT Bangalore
History of GPS
LORAN (Long Range Navigation) is a
terrestrial radio navigation system of early 1940s
which enables ships and aircraft to determine
their position and speed from low frequency
radio signals transmitted by fixed land based radio
beacons, using a receiver unit.
The Decca Navigator System was a low frequency
radio navigation system which allowed ships and
aircrafts to determine their position by receiving
radio signals from fixed navigational beacons with
a receiving unit. The system used frequencies from
70 to 129 kHz. It was first deployed during World
War II when the Allied forces needed a system
which could be used to achieve accurate landings.
As was the case with Loran, its primary use was for
ship navigation in coastal waters.
In 1960, the Air Force proposed a radionavigation
system called MOSAIC (Mobile System
for Accurate ICBM (inter continental ballistic
missile Control) that was essentially a 3-D LORAN.
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