UNIVERSITY INSTITUTE OF TECHNOLOGY(B.U)

Submitted byTanmoy ChakraborttyRoll:- L2013-1074Session:- 2012-2016Computer Science And Engineering

GLOBAL POSITIONING SYSTEM(GPS)

Content.What is GPS (global positioning system).

How does GPS works?

GPS signals

Position determination

Block diagram of GPS receiver

Types of GPS systems

Applications of GPS

Future scope of GPS system

Conclusion

Reference

What is GPS (Global Positioning System)

GPS (Global Positioning system) is a type of GNSS(Global Navigation Satellite System).

It is a "constellation" of 24 well-spaced satellites that orbit the Earth and make it possible for people with ground receivers to pinpoint their geographic location.

It allows small electronic receiver to determine the latitude longitude and altitude of a point.

Receivers Calculated the precise time as well as position, which can be used as a reference for scientific experiments.

How does GPS Works?

GPS system consist of three pieces Space Segment. Control Segment. User Segment.

The US Air force maintain these Segments.

Space Segment are the satellites that transmit the position information.

Control Segment are the ground stations that are used to control the satellites and update the information.

The User segment are the receiver that you purchased.

GPS Signals

GPS satellites transmit two radio signals. The signals are mark as L1 and L2.

A Civilian GPS uses the L1 signal frequency (1575.42 MHz) in the UHF band.

While the L2 frequency (1227.60 MHz) is used to measure the ionospheric delay by Precise Positioning Service (PPS) equipped receivers.

All these signals travel by line of sight.

The GPS signal contains three different bits of information which are a pseudo random code, almanac data and ephemeris data.

Position Determination

GPS satellite continually transmits messages containing the time the message was sent. These signals travel at the speed of light through outer space, and slightly slower through the atmosphere.

Useful form of these equations is in term of the

; n=1,2,3,4Wherex, y, z = receiver’s coordinatestc = time correction for the GPS receiver’s clockn = satellite’s numberttn = signal transmitted time for each satellitetrn = signal received time for each satellite

c = speed of light (3 x 108 m/s)This mean, when there is four satellite used, there will be four equation needed for the calculation.The accuracy in this technique is about 1-5 meters.

Block Diagram of GPS Receiver

Types of GPS systems

1. Street navigation systems (SAT-NAV)

2. Sports GPS systems and watches

3. PDA based systems

4. Phones with GPS

5. For kids too

Applications of GPS

The applications of the global positioning system fall into five categories:• Location• Navigation• Timing• Mapping• Tracking

Future scope of GPS System

1. GPS controlling Car (Without Driver)

2. In Defense For Accurate result for attack to enemy.

3. Shopping Cart.

4. Facilities for visually impaired.

5. More advanced Bi-function.

6. The virtual cable.

Conclusion

GPS is a fantastic tool of the 21st century offering many functions: However, received information is not always reliable, and it would have been interesting to see in which cases it is not. Furthermore, the space segment is completely controlled by the American Army which enables them to completely remove the satellite cover in certain countries in the event of a war…

The future of GPS appears to be virtually unlimited; technological fantasies abound. The system provides a novel, unique, and instantly available address for every square yard on the surface of the planet–a new international standard for locations and distances. To the computers of the world, at least, our locations may be defined not by a street address, a city, and a state, but by a longitude and latitude. With the GPS location of services stored with phone numbers in computerized.

Reference

1. https://www.google.co.in/ For Search the topic and image.2. National Research Council (U.S.). Committee on the Future

of the Global Positioning System; National Academy of Public Administration (1995). The global positioning system: a shared national asset: recommendations for technical improvements and enhancements. National Academies Press. p. 16. ISBN 0-309-05283-1. Retrieved August 16, 2013.,

//books.google.com/books?id= FAHk65slfY4C&pg=PA163. https://gps2008.wordpress.com/ for topic GPS4. https://en.wikipedia.org/wiki/Global_Positioning_System5. www.gps.gov6. http://www.slideshare.net