GPS system

1. Presented by
Amit Debnath
15551A2602

4. The Global Positioning System (GPS) is a satellite-based
Navigation system developed and operated by the US
Department of Defense.
GPS is the shortened form of NAVSTAR GPS. This is an
acronym for NAVIGATION System with Time And Ranging Global
Positioning System.
 GPS uses constellation of 24 satellites to determine the
accurate three-dimensional position of the user on the earth.
GPS was originally designed for military use at any time
anywhere on the surface of the earth but soon after proposals it
is made available to civilian users also.

5. The GPS project was proposed in 1973 to overcome the limitations of
earlier navigation systems.
First satellite was launched in 1978 but It became fully operational with
launching of 24th satellite in 1995.
Advances in technology and new demands on the existing system have
now led to efforts to modernize the GPS system and implement the
next generation of GPS III satellites.
In addition to GPS of US, other systems are also in use or under
development, like
RUSSIAN’s - Global Navigation Satellite System (GLONASS)
EUROPEAN’s - Galileo positioning system
INDIA’s - Indian Regional Navigational Satellite System
CHINA’s - Compass navigation system
but these systems are suffered from incomplete coverage of the globe
and failed to made them available for civilian users.

6. Trying to figure out where you are
is probable man’s oldest pastime.
Finally US Dept of Defense decided
to form a worldwide positioning
system.
Also known as NAVSTAR (
Navigation Satellite Timing and
Ranging Global positioning system)
provides instantaneous position,
velocity and time information.

7. Space Segment
Control Segment
User Segment

8. Control
Segment
Space
Segment
User
Segment
Monitor Stations
Ground
Antenn
asMaster Station

9.  24 GPS space
vehicles(SVs).
 Satellites orbit the earth
in 12 hrs.
 6 orbital planes inclined
at 55 degrees with the
equator.
 This constellation
provides 5 to 8 SVs from
any point on the earth.

10.  The control segment comprises of 5 stations.
 They measure the distances of the overhead satellites
every 1.5 seconds and send the corrected data to Master
control.
 Here the satellite orbit, clock performance and health of
the satellite are determined and determines whether
repositioning is required.
 This information is sent to the three uplink stations

11.  The User Segment consists of all earth-based GPS
receivers.
 The user segment is totally user community, both
civilian and military.

12. The GPS uses technique of "triangulation" to find location.
To "triangulate," a GPS receiver measures distance from the satellite using
the travel time of radio signals.
To measure travel time, GPS needs very accurate timing, which is provided
by atomic clocks used in the satellites.
Along with distance, we need to know exactly where the satellites are in
space. This information is obtained by Almanac data transmitted by satellites.
Finally we must correct for any delays the signal experiences as it travels
through the atmosphere.
To compute a positions in three dimensions. We need to have four satellite
measurements. The GPS uses a trigonometric approach to calculate the
positions

13.  They are high-
frequency, low-
power signals
transferred between
the satellite and the
receiver.
 They relay the
information such as
location to the
receiver, who then
makes a
calculation.

14.  (1) Pseudorandom
code, which is the
satellite’s ID.
 (2) Ephermis data,
which shows the
condition and time.
 (3) Almanac data,
where the satellite
should be in orbit at
any particular time.

15.  Triangulation is the
mathematical
principle that explains
how GPS works.
 There are two types of
triangulation: 2-D and
3-D.
 GPS uses 3-D
triangulation. 3-D has
the capability to tell
altitude or height,
while 2-D doesn’t
have that capability.

16.  Triangulation is what
the receiver does after it
gets the signal.
 The radio signals give it
the three possible
spherical locations.
 Then, with the
triangulation principle
in place, it determines
where you are, your
longitude, latitude and
altitude.

17.  Say you’re 10 miles from
Satellite A. You are in a
sphere with a radius 10
miles away from satellite A.
 If you’re 15 miles from
satellite B, then there is
another sphere drawn. And
the same for a third satellite
and its sphere. At the
common point of the
satellites is your location.
A
B
C

18.  There should be a
point where all the
spheres meet from the
triangulation principle.
 Using the information
from the radio signal
and the triangulation,
the receiver can
determine your
location on Earth with
latitude, longitude, and
altitude.

19. The receiver
is
somewhere
on this
sphere.
Signal From One Satellite
Signals From Two
Satellites
Three Satellites (2D
Positioning)
Three Dimensional (3D) Positioning
TRIANGLATION

20. Determining GPS Position

24.  GPS is extremely easy to navigate as it tells you to the direction for
each turns you take or you have to take to reach to your
destination.
 GPS works in all weather so you need not to worry of the climate
as in other navigating systems.
 The GPS costs you very low.
 The most attractive feature of this system is its100% coverage on
the planet.
 It also helps you to search the nearby restaurants, hotels and gas
stations and is very useful for a new place.
 Due to its low cost, it is very easy to integrate into other
technologies like cell phone.
 This is the best navigating system in water as in larger water
bodies we are often misled due to lack of proper directions.
 Accuracy can vary from milli meters to several meters depending
on the technique that is used.

25.  Satellite surveying can be a one-person operation with significant
savings in time and labour.
 Operators do not need high levels of skill.
 Position may be fixed on land,at sea or in the air.

26.  Surveying:-Most mines now use RTK GPS systems for
surveying. GPS considerably speeds up the surveying process
and reduces the time surveyors are in the field often in
vulnerable locations. For example, because the GPS system
gives an absolute position, the tedious process of establishing
field control points is entirely eliminated.

27.  Truck Fleet
Management:-Many
mines are fitting GPS
systems to their trucks for
fleet management
purposes. Trucks can be
assigned to different
loading machines in real
time to improve overall
efficiency. A side safety
benefit is that the central
control station knows at all
times the whereabouts of
each truck in the fleet.
Stand alone GPS is
generally adequate for this
task.

28.  Hazard Avoidance:-GPS systems can be set up to
warn the operator of site hazards. For example a
hazard warning system has been set up as a trial on a
dozer at the Gladstone Port Authority. Coal from this
stockpile is reclaimed through feeders under the
stockpile. The dozers push the coal into the feeders.
Sometimes the coal bridges, creating a void above the
feeder. If the dozer ventures onto the void it will collapse
and potentially cause a very serious accident. The GPS
system warns the operator when he is getting close to
the feeder position. This is often hard to see when the
stockpile is full of coal.

29.  The dozer is fitted with a cab computer which shows
the dozer in its true position on a map of the site. It is
also fitted with a light bar. More lights progressively
come on as the dozer approaches the hopper
position. At one metre a warning sounds. For the
accuracy required for this system DGPS is quite
adequate–offering substantial savings over an RTK
system.

31.  Collision Avoidance:-Another
possible use of GPS to enhance
safety is in collision avoidance. If all
mobile vehicles are fitted with GPS
and telemetry systems, they can
continuously report their position to a
central control base. Software at the
base can then analyse the data and
warn when two vehicles are on a
collision course, as is done with
civilian air flights in crowded air
corridors. Such a system is possible,
but requires high bandwidth telemetry
systems to poll all rovers on a rapid
basis. This kind of arrangement would
be especially beneficial in areas where
light vehicles and high speed long
distance ore haulers are mixed.

32. Vehicle Tracking and Dispatch:- The dump trucks’
positions obtained are sent to the central control station, where
it is carried the dumping scheduling management. This
application determines which material is loaded and sends
information and instructions to be followed by the truck drivers,
in order to guarantee that the assignments are followed and
the materials are correctly collected from the correct ore block
and dumped in the correct dumping location.
GPS surveying:-The advantage of using GPS for surveying
in open pit mining is that only a single surveyor is required, in
opposition to the conventional methods.
Monitor Drivers and Vehicles:- The sensors in the
vehicle provide monitoring information of equipment’s, like for
instance air pressure. These systems also provide sensors
sent to a central control station. This system will allow for rapid
intervention in case of problems.

33.  Reliability:-The GPS system has
been in place for a long period of time
and has come to be relied on for many
commercial purposes. On May 1st
2000, President Clinton removed the
intentional degradation of GPS signals
known as Selective Availability. A
repeated theme of Presidential
decrees on GPS has been to
"encourage acceptance and integration
of GPS into peaceful civil, commercial
and scientific applications worldwide;
and to encourage private sector
investment in and use of U.S. GPS
technologies and services." It is
unlikely that the US will re-impose
Selective Availability or otherwise
disrupt the GPS system. The use of
reference stations in either DGPS or
RTK effectively negates the effects of
Selective Availability.

35.  Control of heavy machinery such as draglines,
 Control of bucket wheels and dozers,
 Drill guidance,
 Roads grading and maintenance,
 Fleet management systems for haul trucks and other
vehicles tracking and dispatch,
 Asset tracking, for instance, of lighting plant and mobile
generators,
 Guidance and control for drill rigs and explosive trucks,
 Access and zone control for visiting vehicles,
 Detecting dangerous driver behavior and
 Collision avoidance applications.
 Surveying crews can be reduced

37.  The technology is very power hungry, most systems
will only last 8-12 hours before
 needing a battery replacement or recharge.
 The GPS signal is unable to pass through solid
structures so is unable to work
 Can be affected by large buildings and is typically
unreliable in CBD areas.