A

Power Point Presentation

ON

“GLOBAL SYSTEM POSITIONING”

Submitted in partial fulfillment of the requirements for the award of Degree of

BACHELOR OF TECHNOLOGY

In

ELECTRONICS & COMMUNICATION ENGINEERING

Presented by: Presented to:

SAHIL NARANG Mrs. Anurita Singh

Roll No. 08EBNEC044 (Seminar coordinator)

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

BANSAL SCHOOL OF ENGINEERING AND TECHNOLOGY, JAIPUR

2011-2012

GLOBAL POSITIONING SYSTEM

SAHIL NARANG

08EBNEC044

B-SET, JAIPUR

DEFINITION :The Global Positioning System, usually called GPS, is the only fully-functional

satellite navigation system(allow small electronic devices to determine their

location (Longitude, Latitude, and Altitude) in within a few meters using time

signals transmitted along a line of sight by radio from satellites.

SAHIL NARANG

B-SET, JAIPUR

HISTORY OF GPS :

1. 1969-Defense Navigation Satellite System (DNSS) formed

2. 1973-NAVSTAR Global Positioning System developed

3. 1978-first 4 satellites launched Delta rocket launch

4. 1993-24th satellite launched; initial operational capability

5. 1995-full operational capability

6. May 2000-Military accuracy available to all users

SAHIL NARANG

B-SET, JAIPUR

Components of the GPS System :

Space Segment Control Segment User Segment

SAHIL NARANG

B-SET, JAIPUR

Control Segment

Space Segment

User Segment

THREE SEGMENTS OF THE GPS

Monitor Stations

Ground

Antennas

Master Station

SPACE SEGMENT : 24 satellite vehicles

Six orbital planes

Inclined 55o with respect

to equator

Orbits separated by 60o

20,200 km elevation above Earth

Orbital period of 11 hr 55 min

Five to eight satellites visible

from any point on Earth

SAHIL NARANG

B-SET, JAIPUR

CONTROL SEGMENT : Monitor stations

Master control station

Schreiver AFB, Colorado

Ground antennas

Master Control Station

Monitor Station

Ground Antenna

Hawaii

Colorado

Springs

Ascension

IslandsDiego

Garcia

Kwajalein

USER SEGMENT :GPS antennas & receiver/processors

Position

Velocity

Precise timing

Used by

Aircraft

Ground vehicles

Ships

Individuals

SAHIL NARANG

B-SET, JAIPUR

10

HOW THE SYSTEM WORKS

Space Segment

24+ Satellites

Monitor Stations

• Diego Garcia

• Ascension Island

• Kwajalein

• Hawaii

• Colorado Springs

GPS Control

•Colorado Springs

End User

TRIANGULATION

Position is calculated from distance

measurement

Mathematically we need four satellites

but three are sufficient by rejecting the

ridiculous answer

SAHIL NARANG

B-SET, JAIPUR

BREAKING THE CODE :

Transmission Time

Receiver

The Carrier Signal...

combined with…

The PRN code...

Produces the

Modulated signal

which is transmitted, demodulated......

And detected by

receiver,Locked-on,but

With a time delay...Time delay

Satellite

13

DISTANCE MEASURING

•Rate = 186,000 miles per

second

(Speed of Light)

•Time = time it takes signal to travel

from the SV to GPS receiver

Distance = Rate x Time

•Each satellite carries around four

atomic clocks

Accuracy?plus/minus a second over more than

30,000 years!!

The whole system revolves

around time!!!

SAHIL NARANG

B-SET, JAIPUR

PLANNING A NAVIGATION ROUTE :

Start= Waypoint

HOW A RECEIVER SEES YOUR

ROUTE

SAHIL NARANG

B-SET, JAIPUR

ERROR SOURCES :

Earth’s Atmosphere

Solid Structures

Metal

Electro-magnetic Fields

•Ionosphere and troposphere delays

•Signal multipath

•Receiver clock errors

•Orbital errors

•Number of satellites visible

•Satellite geometry/shading

SAHIL NARANG

B-SET, JAIPUR

WHY WE NEED DGPS ?

• DGPS is used to correct the various inaccuracies in the GPS system.

• High performance GPS receiver at a known location.

• DGPS can measure good to couple of meters in moving applications &

better in stationary situations.

• With it, GPS becomes a universal measurement system capable of

positioning things on a very precise scale.

• DGPS gives accuracy of 3-5 meters,while GPS gives accuracy of around

15-20 meters.

SAHIL NARANG

B-SET, JAIPUR

DGPS Site

x+30, y+60

x+5, y-3

True coordinates = x+0, y+0

Correction = x-5, y+3

DGPS correction = x+(30-5) and y+(60+3)

True coordinates = x+25, y+63

x-5, y+3

REAL TIME DIFFERENTIAL GPS

DGPS ReceiverReceiver

SAHIL NARANG

B-SET, JAIPUR

NDGPS Ground Stations :

National Differential Global Positioning System SAHIL NARANG

B-SET, JAIPUR

WIDE AREA AUGMENTATION

SYSTEM (WAAS) System of satellites and ground stations that provide

GPS signal corrections

25 ground reference stations across US

Master stations create GPS correction message

Corrected differential message broadcast through

geostationary satellites to receiver

5 Times the accuracy (3m) 95% of time

Only requires WAAS enabled GPS

SAHIL NARANG

B-SET, JAIPUR

APPLICATION OF GPS TECHNOLOGY :Location

Navigation

Tracking

Mapping

Determining a basic position

getting from one location to another creating maps of the world

monitoring the movement of things

CONCLUSION : GPS provides the accurate location and time information for an unlimited number of

people in all weather condition and any where in the world.

The future of GPS is as unlimited as your imagination.

SAHIL NARANG

B-SET, JAIPUR

REFERENCES :o www.garmin.com/aboutGPS/

o en.wikipedia.org/wiki/Global_Positioning_System

o www.garmin.com/aboutGPS/

o www.colorado.edu/geography/gcraft/notes/gps/gps_f.htm

o mms.nps.gov/gis/gps/How_GPS_Works.ppt

o www.casde.iitb.ac.in/IMSL/motion/gps/Seminar%20on%20GPS.ppt

NASA produced short film that summarizes GPS

http://www.youtube.com/watch?v=wi_3XwkA8cQ

SAHIL NARANG

B-SET, JAIPUR