The History of GPS <ul><li>Feasibility studies begun in 1960 ’s. </li></ul><ul><li>Pentagon appropriates funding in 1973 . </li></ul><ul><li>First satellite launched in 1978 . </li></ul><ul><li>System declared fully operational in April, 1995 . </li></ul>
Historical Development of GPS 1978 -Launch of first GPS satellite . 1985 -Kinematic GPS surveying . 1989 -Launch of first Block II satellite Wide area differential GPs concept U.S Coast Guard GPSInformation System (GPSIC ). 1993 -Real-time Kinematic GPS Initial operational capability (IOC) on December 8 . 1995 -Full operational capability (FOC) on July 17 . 1996 -Presendential Decision Directive, first U.S GPS policy. 2000 - Selective availability set to Zero .
Competitors of GPS <ul><li>GLONASS </li></ul><ul><li>- Russian Federation’s satellite navigation system </li></ul><ul><li>Galileo </li></ul><ul><li>-European Union and the European Space Agency </li></ul>
Introduction <ul><li>The global positioning system(GPS) is a network of 24 NAVSTAR satellites orbiting at a distance of 20,200kms from the surface of the earth . Originally established by the u.s department of defense(DOD). </li></ul>
A visual example of the GPS constellation in motion with the Earth rotating.
Four Basic Functions of GPS <ul><li>Position and coordinates. </li></ul><ul><li>The distance and direction between any two waypoints, or a position and a waypoint. </li></ul><ul><li>Travel progress reports. </li></ul><ul><li>Accurate time measurement. </li></ul>
System Overview The total GPS configuration is comprised of three distinct segments: (1) The space segment-Satellites orbiting the Earth (2) The control segment-Stations positioned on the Earth’s equator to control the satellites. (3) The user segment – Anybody that receives and uses the GPS signal .
Three Segments of the GPS Control Segment Space Segment User Segment Monitor Stations Ground Antennas Master Station
User Segment <ul><li>Military. </li></ul><ul><li>Search and rescue. </li></ul><ul><li>Disaster relief. </li></ul><ul><li>Surveying. </li></ul><ul><li>Marine, aeronautical and terrestrial navigation. </li></ul><ul><li>Remote controlled vehicle and robot guidance. </li></ul><ul><li>Satellite positioning and tracking. </li></ul><ul><li>Shipping. </li></ul><ul><li>Geographic Information Systems (GIS). </li></ul><ul><li>Recreation. </li></ul>
Control Segment Kwajalein Atoll US Space Command Hawaii Ascension Is. Diego Garcia Cape Canaveral Ground Antenna Master Control Station Monitor Station
Position is Based on Time T + 3 Distance between satellite and receiver = “3 times the speed of light” T Signal leaves satellite at time “ T ” Signal is picked up by the receiver at time “ T + 3 ”
Pseudo Random Noise Code Receiver PRN Satellite PRN Time Difference
Calculating Distance <ul><li>Velocity x Time = Distance </li></ul>Radio waves travel at the speed of light, roughly 186,000 miles per second (mps) If it took 0.06 seconds to receive a signal transmitted by a satellite floating directly overhead, use this formula to find your distance from the satellite. 186,000 mps x 0.06 seconds = 11,160 miles
Triangulation <ul><li>Geometric Principle: </li></ul><ul><li>You can find one location if you know its distance from other, already-known locations . </li></ul>
Latitude and Longitude <ul><li>Latitude and Longitude : are spherical coordinates on the surface of the earth. Latitude is measured North or South of the Equator. Longitude is measured East or West of Greenwich. GPS uses Latitudes and Longitudes to reference locations. </li></ul>
A simple question? <ul><li>How to recover </li></ul><ul><li>A stolen car? </li></ul><ul><li>1-Know it’s place </li></ul><ul><li>2-Lock it </li></ul><ul><li>3-Go & Get it </li></ul>
How to know the stolen car place? GPS Chip receive The satellites signals And generate the Latitude and Longitude A mobile based System send (Lat&Lon) via SMS/GPRS To the car owner By using any mapping Software We can know Were the car is.
How to Lock the stolen car ? A built in µ.controller hold a text or a code about The lock operation. The car owner Communicate with The µ.controller Via SMS/GPRS To lock the car. The µ.controller start To perform the Lock Operation by cutting The power off.
Extracting or Parsing the GGA string A program can be written to serially read the incoming message strings and determine if it's a GPGGA message . If so, the program can extract and / or display only geospatial information we might want, like the time and longitude / latitude coordinates .
Thank you Presented by : student / MOHAMED MAGHRBY
Sample frame sent to Nokia 3310 ( showed as a Hex dump ) Byte : 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 Data : 1E 00 0C D1 00 07 00 01 00 03 00 01 60 00 72 D5 Byte 0 : This is the F - Bus Frame ID . Cable is 0x1E . Byte 1 : the destination address 00 for the phone . Byte 3 : This is the message type or 'command' . Byte 2 : source address . PC's ID byte . 0x0C ( Terminal ). Byte 4&5 : the message length 4 is MSB & 5 is LSB
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