This PPT is about the functioning of GPS as well as the latest advances in GPS

1. LATEST ADVANCES IN
GPS TECHNOLOGY
Presented by:
M. Gautam Raj
B.Tech, ECE.

2. Contents
 Short review of GPS
 Segments of GPS
 Functioning of GPS
 Applications
 Current Technology
 Future Technology
 Glimpse of Future
 Conclusion
Latest Advances in GPS Technology

3. Global Positioning System
 GPS is satellite based Navigational system developed and
operated by US department of Defense.
 Constellation of 24+ satellites in Earth orbit
 Global coverage, 24 hours a day, all weather conditions
 Two classes of signals
– Civilian (free of direct user fees)
– Military (encrypted for US/allies)
 Signal frequencies
– L1 - 1575.42 MHz (C/A and P-codes)
– L2 - 1227.60 MHz (P-code only)
Latest Advances in GPS Technology

4. Segments of GPS
• Space segment
• Control segment
• User segment
Latest Advances in GPS Technology

5. Space Segment
• 24 GPS space vehicles (SVs) placed in 6
orbits.
• 6 orbital planes inclined at 55 degrees
with the equator.
• Satellites orbit the earth in 12 hrs.
• This constellation provides 5 to 8 SVs
from any point on the earth.
Latest Advances in GPS Technology

6. Control Segment
• The control segment comprises of 5 ground stations located on equator.(4-
monitor and 1-master control station)
• Monitor stations measure the distances of the overhead satellites every 1.5
seconds and sends the data to Master control.
• In Master control the satellite orbit, precise time and health of the satellite are
determined and determines whether repositioning is required.
• This information is sent back to the satellites using ground antennas.
Latest Advances in GPS Technology

7. User Segment
• It consists of receivers that decodes the signal from the satellites.
• The receiver performs following tasks:
• Selecting 3 or more satellites
• Acquiring GPS signals
• Measuring and tracking
• Acquiring navigation data
Latest Advances in GPS Technology

8. How does the GPS work?
Latest Advances in GPS Technology
Satellites broadcast
• Precise time
• Orbit data
• Satellite health
Receiver measures time
delay from satellites, and by
triangulation calculates
• Location
• Elevation
• Velocity

9. How does the GPS work?
• 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.
• Atomic clocks are the most accurate timekeepers in the world.
• Along with distance, we need to know exactly where the satellites are in space.
• Finally we must correct for any delays
Latest Advances in GPS Technology

10. Triangulation
Latest Advances in GPS Technology

11. Triangulation
Latest Advances in GPS Technology
The receiver is
somewhere on
this sphere.
Signal From One Satellite
Signals
From Two
Satellites
Three Satellites
(2D Positioning)
Three Dimensional
(3D) Positioning

12. Differential GPS
• To obtain more accurate
measurements than a single GPS
unit, DGPS systems are used.
• The GPS unit in the field receives
data from the GPS satellites and
the other GPS receiver on the
ground through a radio signal.
• The GPS error from the known
position is compared to that of the
GPS receiver in the unknown
location.
Latest Advances in GPS Technology

13. Applications
• Recreation
• Navigation (Airways ,Waterways & Roadways)
• Construction
• Boundary Mapping
• Surveying
• Search and Rescue
• Precision Agriculture/Forestry
Latest Advances in GPS Technology

14. Current Technology
Machine Guidance and Automation
Latest Advances in GPS Technology
Guidance Systems
Unique opportunities - ability to work accurately
at night

15. Current Technology
Machine Guidance and Automation
Latest Advances in GPS Technology

16. Current Technology
Location of Soldier in War
Latest Advances in GPS Technology

17. Current Technology
Latest Advances in GPS Technology
Wireless and Touch Screens

18. Future Technology
Dust and Motes
Latest Advances in GPS Technology

19. Future Technology
Latest Advances in GPS Technology
GPS wrist Bands Portable GPS with Music Player

20. Future Technology
Latest Advances in GPS Technology
Positioning Head Gear
Autonomous Tractors

21. Indian Regional Navigation Satellite System
• Indian version of US GPS
-Under ISRO satellite Centre
-It would consist of a constellation of seven satellites and a support ground segment
-Hoping to have all satellites in Orbit by March 2015
• Applications
-Missile Guidance
-Navigation
-Precision Weather Forecast
-Military Applications
Latest Advances in GPS Technology

22. Glimpse of the future …
• GNSS (global navigation satellite system) =
Galileo + GPS + GLONASS
• SV constellation
– More than doubled when entire Galileo network is in place
– Improves precision and reliability of the constellation
Latest Advances in GPS Technology

23. Summary
• GPS performance is better than ever and will
continue to improve
• Enhanced GPS usage
• Integration of wireless technology
• New and cheaper technology
Latest Advances in GPS Technology

24. Latest Advances in GPS Technology

25. Latest Advances in GPS Technology
T + 3
Then distance between satellite and
receiver = “3 times the speed of
light”
T
Radio waves travel at the speed of
light. If GPS signal leaves satellite at
time “T”…
…and is picked up by the
receiver at time “T + 3.”
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