gps_navigation

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					                GPS NAVIGATION




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INTRODUCTION
 The GPS is a satellite based Radio Navigation system,
  that utilizes precise range measurements from the
  GPS satellites to determine precise position anywhere
  in the world.
NAVIGATION
 Navigation is used for
  estimating the position of a
  vehicle on sea, in air or and            NAVIGATION
  on land to ensure that the
  chosen route is followed
  accurately.

                                       TWO                  PATH
 GPS satellites                   DIMENTIONAL           NAVIGATION

  constellations orbit consists
                                           Fig 3.3 Navigation Lay out
  of 24 satellites orbiting in 6
  orbits, 4each.they are
  orbiting around earth in
  every 12 hours emitting
  continuous navigation
   HOW DOES IT WORK?

 GPS provides specially coded
  satellite signals that can be
  processed in a GPS receiver,
  enabling the receiver to
  compute position, velocity
  and time.

 Four GPS satellite signals are
  used to compute positions in
  three dimensions and the
  time offset in the receiver
  clock.
SEGMENTS OF NAVIGATION
            This Navigation system is divided
             into three important segments.
               Space Segment
               Control Segment
               User Segment

              GPS Positioning Services
               Specified in the Federal
               Radio navigation Plan
               Provides two types of
               services:
                 Precise Positioning
                  Service (PPS)
                 Standard Positioning
                  Service (SPS)
   SATELLITE NAVIGATION
 This is based on measurement
  of the times of arrival of the
  time signals received from 3 or
  more orbiting satellites, whose
  positional coordinates in
  space are also transmitted.

 The limiting pulses are sent
  out by each satellite in the L-
  Band, using spread spectrum
  modulation and are received
  by the GPS Receivers in
  aircrafts or ships.
SATELLITE TRANSMISSION
 The space vehicles transmit two microwave carrier
  signals. The L1 frequency ranging about 1575.42
  MHz carries the navigation message and the SPS
  code signals. The L2 frequency about 1227.60 MHz is
  used to measure the ionospheric delay by PPS
  equipped receiver.

 Three types of binary codes are there which shifts
  the L1 and/or L2 carrier phase.
         • The C/A Code (Coarse Acquisition)
         • The P-Code (Precise)
         • The Navigation Message
MARINE NAVIGATION
Some important words used in marine navigation are
        • Track
        • Course
        • Bearing
        • Heading
        • Turn
POSITION & TIME FROM GPS
  CODE PHASE TRACKING (NAVIGATION):
  PSEUDO-RANGE NAVIGATION
  CARRIER PHASE TRACKING (SURVEYING)
RECEIVER POSITION, VELOCITY
AND TIME




        GPS RECEIVER
POSITION &TIME DETERMINATION
RADIO NAVIGATION
 Radio navigation is the navigation of mobile
  robot or Autonomous Guided Vehicle – AGV.

 Here global refers to the ability to discover
  ones position at any unknown location on
  the planet known as position fix, and update
  that knowledge while moving to fulfill some
  other objective e.g. follows way-points of a
  map.
RADIO NAVIGATION
  The basis of Global Navigation for an AGV is
   reliably gaining a co-ordinate of vector describing
   where the vehicle is in relation to a fixed point on
   the globe.

  This point is generally taken to be the intersection
   of the Greenwich meridian and the equator line of
   latitude, at sea level - in accordance with standard
   geographical practice.

  Using this position information, with reference to a
   map or otherwise, a list of waypoints can be
   generated and followed to allow the vehicle to
   navigate between end points of a journey.
HYPERBOLIC NAVIGATION
RADIO NAVIGATION

  Methods employed in tracking an AGV’s
   positioning.

  Dead-Reckoning

  Inertial Navigation Systems (INS):

  INS Integration with GPS:
WAYPOINT NAVIGATION
 A waypoint is an “address” which defines
  starting point, expected destination point, a
  place to avoid or sometimes the intermediate
  position along the way.

   The Destination Waypoint
   Routes
   Mob (man over board) position waypoint
   Navigating To Single Way Point
CONCLUSION
  Though Navigation was someday an
   unsolved mystery but GPS made it possible
   in all types of Navigation such as Space,
   Ground and Marine Navigations.

  further researches are making it day by day
   more useful and the prediction says that all
   the problems regarding position fixing and
   determination will be solved by the
   development of GPS efficiency

				
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