Global Global PositioningPositioning System System

Presented by:Harvendra singh

IFTM UNIVERSITY MORADABAD

Global Positioning System

• What is GPS?• History of GPS• Working of GPS• Components of GPS• Error of Sources• Applications

History of GPS 1959 The Navy built the first real satellite navigation system,

which it called TRANSIT. 1974 The branches of the military, after having worked on a

GPS system for the past 11 years, launch the first satellite of a proposed 24-satellite GPS system called NAVSTAR.

1978-1985 The military launches 11 more test satellites into space to test the NAVSTAR system, which by then was called simply "the GPS System".

2012 At present, the Air Force manages a constellation of 31 operational GPS satellites, plus three decommissioned satellites that can be reactivated if needed.

Working Of GPSA GPS receiver can tell its own position by using the position data

of itself, and compares that data with 3 or more GPS satellites.To get the distance to each satellite, the GPS transmits a signal to

each satellite. The signal travels at a known speed. The system measures the time delay between the signal

transmission and signal reception of the GPS signal. The signals carry information about the satellite’s location. Determines the position of, and distance to, at least three

satellites. The receiver computes position using TRILATERATION.

GPS TRILATERATION• Each satellite knows its

position and its distance from the center of the earth.

• Each satellite constantly broadcasts this information.

• With this information and the calculated distance, the receiver calculates its position

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Components of the GPS

S p ace S eg m en t C on tro l S eg m en t U ser S eg m en t

G P S

Space Segment• GPS satellites fly in circular orbits at an altitude of

20,200 km and with a period of 12 hours.• Orbital planes are centered on the Earth.• Each satellite makes two complete orbits each

sidereal day. • It passes over the same location on Earth once each

day.

Control Segment

• The Control Segment consists of 3 entities:– Master Control Station– Monitor Stations– Ground Antennas

User Segment• The user's GPS receiver is the User Segment of the

GPS system.• They include a display for showing location and

speed information to the user.• A receiver is often described by its number of

channels this signifies how many satellites it can monitor simultaneously.

Error Sources in GPS• 95% due to hardware ,environment and atmosphere• Intentional signal degradation

– Selective availability– Anti spoofing

GPS for Construction Industry- The ability of GPS to provide real-time sub-metre and centimetre level accuracy has significantly changed the construction industry.

In road construction and earth moving,GPS, combined with wireless communication and computer systems, is installed on board the earth-moving machine.

Fig. GPS for open-pit mining Mining and Tunnelling Surveys- GPS has significantly

improved several mining operations such as drilling, vehicle tracking and surveying.

GPS is also used in other phases of the mining cycle, for example, checking the coordinates of the individual points and in volume surveying.

Application of GPS in Military

The military uses GPS systems on bombs, armored vehicles, ships, aircraft, and many more defense systems vital to the survival of out soldiers.

Use of GPS in Daily life Now a days GPS is coming in Android phones and Cars for navigation of roads.

Advantages• It helps to survey with many times greater Precision.• It helps to complete a Survey with lesser time and

thus helps to cut down the Completion Period.• It Reduces the Difficulty of taking manual

measurements to great extent.• With GPS there is a very less chances of error. And

this error may come only due to the Instrument malfunction.

Disadvantages• The main Disadvantage is that, it requires high initial

investments.• To conduct such High End Survey works and to

operate such Electronic Equipments much skilled persons are required.