GPS Overview Part 5 - Competitors
The original theory behind Location-Based Services - or
LBS - is to help you find out where you are or where something else is.
One part of LBS is the GPS satellite
constellation. The following overview describes the history and workings of
GPS, as well as its uses and the future for it.
As it stands at the moment there are two satellite
systems being marketed as current and future satellite systems billed as
being able to provide location-based services.
GLONASS is the Russian Federation's
satellite navigation system. In many ways it is very similar to GPS: there
are 24 satellites in the full constellation; each satellite transmits various
data on two L-band carriers; there is one navigation signal that has been
authorised for civilian use, and further navigation signals that have been
reserved solely for Russian military use; there is a ground segment that
monitors and control the satellites; and users passively receive its signals
and are able to navigate with accuracy's of few tens of metres or better.
However, it is too easy from a user's
perspective to presume that GLONASS is the same as GPS. Rather, there are
some key differences between the two systems. In many ways, GLONASS is a more
elegant and economical system design than GPS. Unfortunately there are a
number of quality control issues and much more serious funding problems. The
GLONASS system was declared fully operational on 18 January 1996. Since then
there have been few occasions when the full complement of 24 satellites was
operating. In addition to satellite outages eight satellites have been
withdrawn from service since this date. So by late 1997 only 15 satellites
were available for navigation.
Thankfully though, recent announcements
by Russian officials may mean that 6 years of neglect of the GLONASS
constellation of satellites will stop. Solid government financial
commitments have been obtained to return the system to fully operational
status by 2006, Russian officials say. Also, this new generation of GLONASS
satellites (Glonass-M) will have longer in-orbit lives that should ease
pressure on the system, they said. They are designed to have a seven-year
service life, compared to three years for the current GLONASS. Whether this
financial commitment will materialise is another thing, but even in its
current weakened state, GLONASS still has potential as a stand-alone
navigation system, and as an augmentation to GPS.
The Galileo satellite
radio navigation system is an initiative launched by the European Union and
the European Space Agency (ESA).The project architects plan deployment in
2006-7, becoming operational in 2008 at a yearly cost of €220m. It is
projected by 2008 a constellation of 30 satellites should be
available.The technology behind Galileo is designed to be more accurate and
more reliable than GPS or GLONASS. This will allow safety-critical systems -
such as air traffic control, and ship and car navigation - to be run on the
technology. The system should also guarantee coverage to previously
inaccessible areas such as those that are either blocked by buildings or
isolated areas at high latitudes.
However it is estimated that the Galileo project could cost more
than €3bn ($2.6bn). With some of the member countries facing recession, now
might not be the time to fund the idea. Britain and the Netherlands have
already questioned the timing, and Germany has raised issues over costs. In
contrast, France and Italy whose aerospace industries both stand to benefit
from the system are looking forward to a go-ahead. The decision to push ahead
with the project remains up in the air for now.
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