Global Positioning System

Presented by:

Prateek Rastogi

(05IT6013)

What is GPS?

Global Positioning System.

System to Identify the Position on Globe.

Network Of Satellites.

Segments Of GPS

The Space Segment

The Control Segment

The User Segment

The Space SegmentConsists of 24 satellites in 6 orbits.

Each satellites transmits low powered radio signals.

GPS SatelliteName : NAVSTAR

Altitude : 11,000 miles

Inclination : 55 Deg to the Equator

Weight : 863 Kg(in orbit)

Orbital Period :12 hrs

The Control SegmentA Master Control Station

Unmanned Monitor Stations

Large Ground-antenna Stations

The User SegmentUsers-Military and Civilians

GPS ReceiversDecodes the signals from Satellites.Calculate the distance.

Modes of OperationStandard Positioning System

Data Transmitted on L1 Frequency

For civil users

Accuracy is degraded

Precise Positioning SystemData Transmitted on L1 and L2 Frequencies

For Military users

Highly Accurate

HA=100m

VA=156m

TA=340ns

HA=22m

VA=27.7m

TA=200ns

Signals from GPS

Coarse/Acquisition- To determine Pseudo range

1023 bit long

1.023Mega-bits per sec

P Code2.3547*10^14 bit long

10.23 Mega-bits per sec

Navigation Massage

Working Of GPS

How User Segment calculates the position?

Calculation of Position Satellites Location

Almanac data

Ephemeris

Time is the essenceVelocity * Time=distance

Determination of PositionTrilateration

Sources of Errors

Ionosphere Delays

Troposphere Delays

Clock Error

Multi-path Error

Relativity Error

Correction of Errors

Error ModelingMathematical Model

Data Frequency MeasurementCompare the Delays of L1 and L2

ApplicationsIndustry

Agriculture

Mapping & GIS Data Collection

Public safety

Surveying

Telecommunication

Application Contd…..Military

Intelligence & Target Location

Navigation

Weapon Aiming &Guidance

TransportationAviation

Fleet Tracking

Marine

Application Contd…

Science

Archaeology

Atmospheric Science

Environmental

Geology & Geophysics

Oceanography

Wildlife

Referenceswww.trimble.com

GPS primer “A Student Guide”(Aerospace Corporation)

An Introduction – Global Positioning system S. K. Upadhyaya, G. S. Pettygrove, J.W. Oliveira, B. R. Jahn1

GPS Guide for Beginners(GARMIN Corporation)