PRESENTATION BASED ON GPS

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PRESENTATION BASED ON GPS
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Introduction To GPS
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GPS is a spaced based radio positioning system,
which provide suitably equipped user with highly
accurate position, velocity and time data

• GPS provide specially coded signals that can be
  processed in a GPS receiver.
• A GPS receiver decodes time signal transmission
  from multiple satellites and calculated its
  position.

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• GPS system was designed controlled by US
  military.
• The cost of maintaining the system is
  approximately US 400 million per year including
  the replacement of aging satellite.

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Earth

• Circumference
• 24,900 Miles
• Rotation
• 1,038 Miles/Hour
• 1 Day Cycle

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Moon

• 1/4 Size of the Earth
• Distance from Earth
• 239,000 Miles

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The History of GPS

• Feasibility studies begun in 1960s.
• Pentagon appropriates funding in 1973.
• First satellite launched in 1978.
• System declared fully operational in April, 1995.
• Open to the public, 2000.

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How does GPS work?

• Stations on earth, and a GPS receiver, the
  distances between each of these points can be
  calculated.
• The distance is calculated based on the amount of
  time it takes for a radio signal to travel
  between these points.
• Using satellites in the sky, ground allows the
  GPS receiver to know where you are, in terms of
  latitude and longitude, on the earth.

• The more satellites the GPS can see, the more
  accurate your reading.
• The GPS must see the satellites, so it does not
  work well in dense forests, inside caves,
  underwater, or inside buildings.

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GPS Satellites
Distance from Earth 12,000 Miles 2 Orbits in 24
Hours Travel 7,000 MPH Powered by Solar Energy
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Satellites Segments
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Three major segment of GPS system

• Space segment
• Control segment
• User segment

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Space segment -

• A space segment contain 24 satellites.
• The satellite arranged such that a minimum of
  four satellite is in view to a user at any time
  on a world wide basis.
• Each satellite transmits signals on two radio
  frequencies, superimposed on which are navigation
  and system data.
• The satellite orbit in six separate orbital
  planes.

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• 24 satellites in six orbital plane
• 12,000 miles above Earth
• Orbit twice daily
• At least 4 satellites in view
• Distance from Earth to Moon - 256,000 miles

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• 4 satellite in each plane
• 20,200 km altitude 55 degree inclination.

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Control Segment

• The control segment includes a master control
  station(MCS).
• A number of monitor stations, and ground antennas
  throughout the world.
• The master control station, located in Colorado
  Springs.
• Colorado consists of equipment and facilities
  required for satellite monitoring, tracking,
  commanding, control, uploading, and navigation
  message generation.

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User Segment

• Military.
• Search and rescue.
• Disaster relief.
• Surveying.
• Marine, aeronautical and terrestrial navigation.
• Remote controlled vehicle and robot guidance.
• Satellite positioning and tracking.
• Shipping.
• Geographic Information Systems (GIS).
• Recreation.

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What does a GPS receiver do?

• GPS receiver allows you to pinpoint your
  location, anywhere in the world, based on
  latitude and longitude coordinates.
• It can tell you in what direction you are
  heading.
• It can show you
• how fast you are going
• your altitude
• a map to help you arrive at a destination

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Signal From One Satellite
The receiver is somewhere on this sphere.
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Signals From Two Satellites
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Three Satellites (2D Positioning)
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Three Dimensional (3D) Positioning
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How GPS Works
Ok, youre lost, you have amnesia, and you have
absolutely no idea where you are. You go up to
someone, and like a good amnesiac you ask, Where
Am I? This person tells you that you are 625
miles from Boise, Idaho. You say, sarcastically,
Wow, thats some great information. Thanks
Buddy.
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Were Getting Closer
You still have absolutely no idea where you
are, so once again you go up to someone and ask,
Where Am I? This person tells you that youre
690 miles from Minneapolis. You just scratch your
head, but then you start to remember what you
learned in GPS class, and, with the US map in
your pocket to guide you, you proceed.
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Now We Know!
You see a another smiling face and ask where
am I one more time. This time you get the reply
you are 615 miles from Tucson. The light pops on
in your brain. Its all clear now. You draw three
circles extending in the radii of 625 miles from
Boise, 690 from Minneapolis, and 615 miles from
Tucson. The circles intersect in Denver! Arent
you glad that you took this class?
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GPS by Trilateration
GPS Distance D Speed of Light x Time or D
CT
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Waypoint

• A waypoint is based on coordinates entered into a
  GPS receivers memory.
• It can be either a saved position fix, or user
  entered coordinates.
• It can be created for any remote point on earth.
• It must have a receiver designated code or
  number, or a user supplied name.
• Once entered and saved, a waypoint remains
  unchanged in the receivers memory until edited
  or deleted.

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