PSGLOBAL POSITIONING SYSTEM

Darpan Dodiya

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Overview• I N T R O D U C T I O N

• H I S T O R Y

• H O W I T W O R K S ?

• L I M I T A T I O N S A N D E R R O R S O U R C E S

• A P P L I C A T I O N

• A L T E R N A T I V E S

• C O N C L U S I O N

GPS

Introduction

• A very precise positioning system

• Developed and maintained by the US Department of Defense (DOD)

• Only one fully functional Navigation System in the world.

• Satellite Based

* 24 satellites* 20,200 km high orbit

Introduction

• Free• Precise• Reliable

• Anytime & anywhere• All weather

• Unlimited user capacity

Features of GPS

Almost!

HistoryBasic question of mankind: where am I? ….which leads to…

where am I going and

how do I get there?

Early Solutions:• Marking trails with piles of stones• Navigating by stars: most widely used for centuries

Modern Ideas:• LORAN: radio-based• Sat-Nav: low orbit satellites;

GPS Started in 1973 Fully operational in 1995

How it works?

Space Segment

Control Segment

User Segment

3 Parts

How it works?

• 24 GPS space vehicles(SVs).

• Satellites orbit the earth in 12 hrs.

• 6 orbital planes inclined at 55 degrees with the equator.

• This constellation provides 5 to 8 SVs from any point on the earth.

Space Segment:

How it works?

Control Segment:

• Comprises of 6 stations

• Measures the distances of the overhead satellites and send to Master control.

• Here the satellite orbit, clock performance and health of the satellite are determined

• This information is sent to the three uplink stations

How it works?

User Segment:

• It consists of receivers that decode the signals from the satellites.

• The receiver performs following tasks:

• Selecting one or more satellites

• Acquiring GPS signals

• Measuring and tracking

• Recovering navigation data

How it works?Velocity x Time = Distance

Radio waves travel at the speed of light, roughly 186,000 miles per second ( mps)

Geometric Principle : You can find one location if you know its distance from other, already -known

locations.

Limitations & GPS Errors

• Indoor unavailability

• Satellite geometry

• Satellite orbits

• Multipath effect

• Atmospheric effects

• Clock

• Quality of GPS Receiver

Applications

Agriculture Timing Survey & Map

Road & Highways Disaster Control Railway

Marine

Space

Recreation

Aviation

Alternatives

• Russian GLONASS – Fully operational worldwide

• European Galileo Positioning System

• Chinese COMPASS navigation system

• Indian IRNSS.

• French DORIS.

That’s all we have for you!

Thank you!

Good day!

ConclusionVerdict:

GPS is the ultimate navigation system currently in the world in terms of cost, performance & reliability